Urticaria
Encyclopedia
Urticaria (or hives) is a kind of skin rash notable for pale red, raised, itchy bumps. Hives is frequently caused by allergic
reactions; however, there are many non-allergic causes. Most cases of hives lasting less than six weeks (acute urticaria) are the result of an allergic trigger. Chronic urticaria (hives lasting longer than six weeks) is rarely due to an allergy. The majority of patients with chronic hives have an unknown (idiopathic
) cause. Perhaps as many as 30–40% of patients with chronic idiopathic urticaria will, in fact, have an autoimmune cause. Acute viral infection is another common cause of acute urticaria (viral exanthem
). Less common causes of hives include friction, pressure, temperature extremes, exercise, and sunlight.
Weal
s (raised areas surrounded by a red base) from urticaria can appear anywhere on the surface of the skin. Whether the trigger is allergic or non-allergic, there is a complex release of inflammatory mediators, including histamine
from cutaneous mast cells, resulting in fluid leakage from superficial blood vessels. Wheals may be pinpoint in size, or several inches in diameter. Angioedema
is a related condition (also from allergic and non-allergic causes), though fluid leakage is from much deeper blood vessels. Individual hives that are painful, last more than 24 hours, or leave a bruise as they heal are more likely to be a more serious condition called urticarial vasculitis
. Hives caused by stroking the skin (often linear in appearance) are due to a benign condition called dermographism
.
usually show up a few minutes after contact with the allergen, and can last a few hours to several weeks. Food allergic reactions often fit in this category.
refers to hives that persists for 6 weeks or more. There are no visual differences between acute and chronic urticaria. Some of the more severe chronic cases have lasted more than 20 years. A survey indicated that chronic urticaria lasted a year or more in more than 50% of sufferers and 20 years or more in 20% of them.
This most common type of Urticaria stands in contrast to the linear reddening that does not itch witnessed in healthy people that are scratched. In most cases the cause is unknown, although it may be preceded by a viral infection, antibiotic therapy, or emotional upset. Dermographism is diagnosed by taking a tongue blade and drawing it over the skin of the arm or back. The hives should develop within 1 to 3 minutes. Unless the skin is highly sensitive and reacts continually, treatment is not needed. Taking antihistamines can reduce the response in cases that are annoying to the patient.
It is believed that histamine is discharged in response to stimulation by the parasympathetic nervous system. Cholinergic Urticaria is diagnosed by historical measures and also multiplying the hives under certain conditions. Several times, the patient is asked to exercise by jogging instead of riding a stationary bike and the time it takes for hives to develop is noted down. Cholinergic Urticaria can be treated by delimiting the strenuous exercise. This type of Urticaria responds well to a medication named hydroxyzine, which serves as an antihistamine. However, the principal side effect of sleepiness is often not tolerated well. Standing under a shower of hot water may cause a release of histamine throughout the body, exhausting histamine stores and causing a 24-hour refractory period.
Severe reactions can be witnessed with exposure to cold water. Swimming in cold water is the most commonplace cause of a severe reaction. This can cause a massive discharge of histamine ensuing in low blood pressure, fainting, shock and even loss of life. Cold Urticaria is diagnosed by dabbing an ice cube against the skin of the forearm for 1 to 5 minutes. A distinct hive should develop if a patient is down with cold Urticaria. This is different than the normal redness that can be viewed in people without cold Urticaria. Patients with cold Urticaria needs to learn to protect themselves from a hasty drop in body temperature. Regular antihistamines however are not generally efficacious. The particular antihistamine, cyproheptadine (Periactin) has been found to be of much usefulness. The tricyclic antidepressant doxepin has also been found to be an effective blocking agent of histamine discharge. Finally, a medication named ketotifen, which keeps mast cells from discharging histamine, has also been employed with widespread success.
Exercise-Induced anaphylaxis sometimes comes about only when someone exercises within 30 minutes of eating particular foods such as wheat and shellfish. For these individuals, exercising alone or eating the injuring food without exercising, produces no symptoms. Such type of Urticaria can be diagnosed by having the patient exercise and then observing the symptoms that germinate. This method must be utilised with caution and only in such a circumstance with the appropriate resuscitative measures ready at hand. Exercise-induced anaphylaxis can be differentiated from cholinergic Urticaria by the hot water immersion test. In this test, the patient is immersed in water at 43 degrees Celsius (109.4 degrees Fahrenheit). Someone with exercise-induced anaphylaxis will not develop hives, while a person with cholinergic Urticaria will develop the characteristic small hives, especially on the neck and chest.
The immediate symptoms of this uncanny type of Urticaria are treated with antihistamines, epinephrine and airway support. Taking antihistamines prior to exercise may be effective. A medication referred to as ketotifen, is acknowledged to stabilise mast cells and prevents histamine release and has been effective in treating this hives disorder. Avoiding exercise or foods that cause the mentioned symptoms, is very important. In particular circumstances, tolerance can be brought on by regular exercise, but this must be under secure medical supervision.
is similar to urticaria, but in angioedema, the swelling occurs in a lower layer of the dermis than it does in urticaria, as well as in the subcutis. This swelling can occur around the mouth, in the throat, in the abdomen, or in other locations. Urticaria and angioedema sometimes occur together in response to an allergen
and is a concern in severe cases as angioedema of the throat can be fatal.
(trade name Amaryl), in particular, has been documented to induce allergic reactions manifesting as urticaria. Other cases include dextroamphetamine
, aspirin
, ibuprofen
, penicillin
, clotrimazole
, sulfonamide
s and anticonvulsant
s.
and nut
s. The most common food allergies in children are shellfish
, nuts, peanut
s, eggs
, wheat
, and soy. It is uncommon for patients to have more than 2 true food allergies. A less common cause is exposure to certain bacteria, such as streptococcus
or possibly Helicobacter pylori
.
(Fasciola hepatica
) and ascariasis (Ascaris lumbricoides
).
The rash that develops from poison ivy
, poison oak
, and poison sumac
contact is commonly mistaken for urticaria. This rash is caused by contact with urushiol
and results in a form of contact dermatitis
called Urushiol-induced contact dermatitis
. Urushiol is spread by contact, but can be washed off with a strong grease/oil dissolving detergent and cool water and rubbing ointments.
, and resulting in an edema
which persists until the interstitial fluid
is absorbed into the surrounding cells.
Urticaria are caused by the release of histamine
and other mediators of inflammation (cytokines) from cells in the skin. This process can be the result of an allergic or non-allergic reaction, differing in the eliciting mechanism of histamine release.
Allergic urticaria : Histamine and other pro-inflammatory substances are released from mast cells in the skin and tissues in response to the binding of allergen
-bound IgE
antibodies to high affinity cell surface receptors. Basophils and other inflammatory cells are also seen to release histamine and other mediators, and are thought to play an important role, especially in chronic urticarial diseases.
Autoimmune urticaria : In the past decade, it has been noted that many cases of chronic idiopathic urticaria are the result of an autoimmune trigger. For example, roughly one third of patients with chronic urticaria spontaneously develop auto-antibodies directed at the receptor FcεRI located on skin mast cells. Chronic stimulation of this receptor leads to chronic hives. Patients often have other autoimmune conditions such as autoimmune thyroiditis
.
Infections : Hive-like rashes commonly accompany viral illnesses, such as the common cold. They usually appear 3–5 days after the cold has started, and may even appear a few days after the cold has resolved.
Non-allergic urticaria : Mechanisms other than allergen-antibody interactions are known to cause histamine release from mast cells. Many drugs, for example morphine
, can induce direct histamine release not involving any immunoglobulin molecule. Also, a diverse group of signaling substances called neuropeptides have been found to be involved in emotionally induced urticaria. Dominantly inherited cutaneous and neurocutaneous porphyrias (porphyria cutanea tarda
, hereditary coproporphyria
, variegate porphyria
and erythropoietic protoporphyria
) have been associated with solar urticaria
. The occurrence of drug-induced solar urticaria
may be associated with porphyrias. This may be caused by IgG binding not IgE
.
Dietary histamine poisoning : This is termed scombroid food poisoning. Ingestion of free histamine released by bacterial decay in fish flesh may result in a rapid-onset allergic-type symptom complex which includes urticaria. However, the urticaria produced by scombroid is reported not to include wheals.
Stress and chronic idiopathic urticaria : Chronic idiopathic urticaria has been anecdotally linked to stress since the 1940s. There is a large body of evidence demonstrating an association between this condition and both poor emotional well-being and reduced health related quality of life
. A link between stress and this condition has also been shown. A recent study involving the Department of Immunology at Derriford Hospital and the University of Plymouth has demonstrated an association between stressful life events (e.g. bereavement, divorce, etc.) and chronic idiopathic urticaria and also an association between posttraumatic stress and chronic idiopathic urticaria.
, require a day or two to build up to effective levels and since the condition is intermittent and outbreaks typically clear up without any treatment.
Most treatment plans for urticaria involve being aware of one's triggers, but this can be difficult since there are several forms of urticaria and people often exhibit more than one type. Also, since symptoms are often idiopathic
(unknown reason) there might not be any clear trigger. If one's triggers can be identified then outbreaks can often be managed by limiting one's exposure to these situations.
s such as fexofenadine
, diphenhydramine
, hydroxyzine
, cetirizine
and other H1 receptor
antagonists. These are taken on a regular basis to protective effect, lessening or halting attacks. Treatments such as stress management
can sometimes lessen severity and occurrence. Additionally, methods similar to psychological pain management can be used to shift focus away from the discomfort and itchiness during an attack.
s, such as doxepin
, also are often potent H1 and H2 antagonists and may have a role in therapy, although side effects limit their use. For very severe outbreaks, an oral corticosteroid
such as Prednisone
is sometimes prescribed. However this form of treatment is controversial because of the extensive side effects common with corticosteroids and as such is not a recommended long-term treatment option. For acute urticaria, some topical creams such as Hydrocortisone, Fluocinonide, Desonate can also be prescribed to relieve itching. To boost relief for severe anaphylactic urticaria, a dermatologist will also administer steroid shots intramuscularly.
As of 2008 an Australian company is performing clinical trial
s with an analogue of alpha-melanocyte-stimulating hormone
called afamelanotide
(formerly CUV1647) for the treatment of solar urticaria, a type of urticaria that develops in response to exposure to specific wavelengths of light.
Allergy
An Allergy is a hypersensitivity disorder of the immune system. Allergic reactions occur when a person's immune system reacts to normally harmless substances in the environment. A substance that causes a reaction is called an allergen. These reactions are acquired, predictable, and rapid...
reactions; however, there are many non-allergic causes. Most cases of hives lasting less than six weeks (acute urticaria) are the result of an allergic trigger. Chronic urticaria (hives lasting longer than six weeks) is rarely due to an allergy. The majority of patients with chronic hives have an unknown (idiopathic
Idiopathic
Idiopathic is an adjective used primarily in medicine meaning arising spontaneously or from an obscure or unknown cause. From Greek ἴδιος, idios + πάθος, pathos , it means approximately "a disease of its own kind". It is technically a term from nosology, the classification of disease...
) cause. Perhaps as many as 30–40% of patients with chronic idiopathic urticaria will, in fact, have an autoimmune cause. Acute viral infection is another common cause of acute urticaria (viral exanthem
Exanthem
An exanthem is a widespread rash usually occurring in children. Exanthems can be caused by toxins or drugs, microorganisms, or can result from autoimmune disease.It can be contrasted with an enanthem.-Types:...
). Less common causes of hives include friction, pressure, temperature extremes, exercise, and sunlight.
Weal
Cutaneous conditions
There are many conditions of or affecting the human integumentary system—the organ system that comprises the entire surface of the body and includes skin, hair, nails, and related muscle and glands.- Diseases :...
s (raised areas surrounded by a red base) from urticaria can appear anywhere on the surface of the skin. Whether the trigger is allergic or non-allergic, there is a complex release of inflammatory mediators, including histamine
Histamine
Histamine is an organic nitrogen compound involved in local immune responses as well as regulating physiological function in the gut and acting as a neurotransmitter. Histamine triggers the inflammatory response. As part of an immune response to foreign pathogens, histamine is produced by...
from cutaneous mast cells, resulting in fluid leakage from superficial blood vessels. Wheals may be pinpoint in size, or several inches in diameter. Angioedema
Angioedema
Angioedema or Quincke's edema is the rapid swelling of the dermis, subcutaneous tissue, mucosa and submucosal tissues. It is very similar to urticaria, but urticaria, commonly known as hives, occurs in the upper dermis...
is a related condition (also from allergic and non-allergic causes), though fluid leakage is from much deeper blood vessels. Individual hives that are painful, last more than 24 hours, or leave a bruise as they heal are more likely to be a more serious condition called urticarial vasculitis
Urticarial vasculitis
Urticarial vasculitis is a skin condition characterized by fixed urticarial lesions that appear histologically as a vasculitis.- Introduction :A rare autoimmune disease characterised by recurrent...
. Hives caused by stroking the skin (often linear in appearance) are due to a benign condition called dermographism
Dermatographic urticaria
Dermatographic urticaria is a skin disorder seen in 4–5% of the population and is one of the most common types of urticaria, in which the skin becomes raised and inflamed when stroked, scratched, rubbed, and sometimes even slapped.-Presentation:The symptoms are thought to be caused by mast cells in...
.
Acute
Acute urticariaAcute urticaria
Acute urticaria is defined as the presence of evanescent wheals which completely resolve within six weeks.Acute urticaria becomes evident a few minutes after the person has been exposed to an allergen. The outbreak of acute urticaria may last several weeks, but usually the hives are gone in six weeks...
usually show up a few minutes after contact with the allergen, and can last a few hours to several weeks. Food allergic reactions often fit in this category.
Chronic
Chronic urticariaChronic urticaria
Chronic urticaria is defined as the presence of evanescent wheals which persist for greater than six weeks....
refers to hives that persists for 6 weeks or more. There are no visual differences between acute and chronic urticaria. Some of the more severe chronic cases have lasted more than 20 years. A survey indicated that chronic urticaria lasted a year or more in more than 50% of sufferers and 20 years or more in 20% of them.
Drug-induced type of urticaria
Drugs that have caused allergic reactions evidencing as Urticaria comprise: aspirin, penicillin, sulfonamides, anti-convulsants and anti-diabetic drugs such as suphonylurea. Drug-induced Urticaria has been known to affect upon in severe cardio-respiratory failure. The anti-diabetic sulphonylurea glimepiride (trade name Amaryl), in particular, has been authenticated to induce allergic reactions manifesting as Urticaria. Other such instances include dextroamphetamine and clotrimazole.Physical urticaria
Also medically referred to as Dermatographism or Dermographism, this kind of Urticaria is marked by the appearance of weals or welts on the skin as a result of itching, scratching, or firm stroking of the skin. This is the most common type of physical Urticaria. The skin reaction usually becomes evident soon after the itching and disappears within 30 minutes. Dermographism is a common form of chronic hives. It is also recognised as "skin writing". Dermatographism is the most common form of a subset of chronic hives, acknowledged as `physical hives`. It happens in some degree in approximately 5 percent of the populationThis most common type of Urticaria stands in contrast to the linear reddening that does not itch witnessed in healthy people that are scratched. In most cases the cause is unknown, although it may be preceded by a viral infection, antibiotic therapy, or emotional upset. Dermographism is diagnosed by taking a tongue blade and drawing it over the skin of the arm or back. The hives should develop within 1 to 3 minutes. Unless the skin is highly sensitive and reacts continually, treatment is not needed. Taking antihistamines can reduce the response in cases that are annoying to the patient.
Pressure or delayed pressure
This type of Urticaria can occur right away, precisely after a pressure stimulus or as a deferred response to sustained pressure being enforced to the skin. In the deferred form, the hives only appear after approximately six hours from the initial application of pressure to the skin. Under normal circumstances, these hives are not the same as those witnessed with most Urticarias. Instead, the protrusion in the affected areas is typically more spread out. The hives may last from approximately 8 hours to three days. The source of the pressure on the skin can happen from tight fitted clothing, belts, clothing with tough straps, walking, leaning against an object, standing, sitting on a hard surface, etc. The areas of the body most commonly affected are the hands, feet, the trunk, the buttocks, legs and the face. Although this appears to be very similar to dermatographism, the cardinal difference is that the swelled skin areas do not become visible quickly and tend to last much longer. This form of the skin disease is however, rare.Cholinergic or stress
This form of Urticaria is fairly widespread and occurs after exercise, sweating, or any activity that leads to a warming of the core body temperature such as warm or hot baths or showers. The hives that are produced are typically smaller than the classic hives. In severe cases, hundreds of tiny red itchy spots appear on the skin with exercising, when the individual is warm or when the individual is experiencing a high level of physical or emotional stress. The red spots manifest rather quickly and remain for approximately 60 to 90 minutes on average. It precisely becomes marked as multiple, small, 2 to 3 mm red hives on the upper trunk and arms, although it can occur from the neck to the thighs. Cholinergic type of Urticaria is known to cause itching, tingling, burning and heating-up of the skin.It is believed that histamine is discharged in response to stimulation by the parasympathetic nervous system. Cholinergic Urticaria is diagnosed by historical measures and also multiplying the hives under certain conditions. Several times, the patient is asked to exercise by jogging instead of riding a stationary bike and the time it takes for hives to develop is noted down. Cholinergic Urticaria can be treated by delimiting the strenuous exercise. This type of Urticaria responds well to a medication named hydroxyzine, which serves as an antihistamine. However, the principal side effect of sleepiness is often not tolerated well. Standing under a shower of hot water may cause a release of histamine throughout the body, exhausting histamine stores and causing a 24-hour refractory period.
Cold
The Cold type of Urticaria or hives are caused by exposure of the skin to extreme cold temperatures. In particular, the hives appear on the skin areas that have been exposed to cold, damp and windy conditions. It comes about in two forms. The rare form is hereditary and becomes evident as hives all over the body 9 to 18 hours after cold exposure. The common form of cold Urticaria demonstrates itself with the rapid onset of hives on the face, neck, or hands after exposure to cold. Cold Urticaria is common and lasts for an average of 5 to 6 years. The population mostly impressed upon is young adults, aged between 18 to 25 years. Many people with cold Urticaria also are stung by dermographism and cholinergic Urticaria.Severe reactions can be witnessed with exposure to cold water. Swimming in cold water is the most commonplace cause of a severe reaction. This can cause a massive discharge of histamine ensuing in low blood pressure, fainting, shock and even loss of life. Cold Urticaria is diagnosed by dabbing an ice cube against the skin of the forearm for 1 to 5 minutes. A distinct hive should develop if a patient is down with cold Urticaria. This is different than the normal redness that can be viewed in people without cold Urticaria. Patients with cold Urticaria needs to learn to protect themselves from a hasty drop in body temperature. Regular antihistamines however are not generally efficacious. The particular antihistamine, cyproheptadine (Periactin) has been found to be of much usefulness. The tricyclic antidepressant doxepin has also been found to be an effective blocking agent of histamine discharge. Finally, a medication named ketotifen, which keeps mast cells from discharging histamine, has also been employed with widespread success.
Heat
This rare form of Urticaria is triggered by the merciless application of heat on the skin. Hives begin to germinate within 2 to 5 minutes on the area of the skin that was exposed to heat. The hives however, generally do not last more than an hour.Solar
This is a form of the disease and is stimulated on areas of the skin that have mostly been exposed to the sun. The skin condition becomes evident within minutes of the sun vulnerability. Although, after the individual is no longer exposed to the sun, the condition starts to weaken out within a few minutes to a few hours and hardly ever lasts longer than 24 hours. Solar Urticaria is classified into 6 different types, depending upon the wavelength of light involved. Since glass absorbs light with a wavelength of 320 nanometre and below, people suffering from solar Urticaria in response to wavelengths of less than 320 nanometre are protected by glass.Water
This type of Urticaria is also termed as rare and occurs upon contact with water. The response is not temperature dependent and the skin appears similar to cholinergic form of the disease. The appearance of hives is within 1 to 15 minutes of contact with the water and can last from 10 minutes to two hours. The hives that last for 10 to 120 minutes, do not seem to be stimulated by histamine discharge like the other physical hives. Most researchers believe that this condition is actually most delicate skin sensitivity to additives in the water such as chlorine. Water Urticaria is diagnosed by dabbing tap water and distilled water to the skin and observing the gradual response. Aquagenic type of Urticaria is treated with a cream named as capsaicin (Zostrix), that is administered to the chafed skin. This is the same treatment utilised for shingles. Antihistamines are of questionable benefit in this instance, since histamine is not the conducive factor in water Urticaria.Vibratory angioedema
This is indeed a rare form of hives that develops in reply to contact with vibration. Angioedema is an intense and more painful form of hives. In vibratory angioedema, symptoms develop within 2 to 5 minutes after contact with vibration and dissolve after approximately 1 hour. Patients with this disorder do not suffer from dermographism or pressure Urticaria. Vibratory angioedema is diagnosed by administering a laboratory vortex to the forearm for 4 minutes. Speedy swelling of the whole forearm extending into the upper arm is also noted down later. The principal treatment of vibratory angioedema is avoidance of vibratory stimulants. Antihistamines have also been proven helpful.Exercise-induced anaphylaxis
This type of Urticaria is a condition that was first distinguished in 1980. People with this condition experience hives, itchiness, shortage of breath and low blood pressure 5 to 30 minutes after the inception of exercise. These symptoms can progress to shock and even sudden demise. Jogging is the most common type of exercise that causes exercise-induced anaphylaxis. People with exercise-induced anaphylaxis do not get these symptoms after a hot shower, fever, or with fretfulness. This marked element indeed severalises exercise-induced anaphylaxis from cholinergic Urticaria.Exercise-Induced anaphylaxis sometimes comes about only when someone exercises within 30 minutes of eating particular foods such as wheat and shellfish. For these individuals, exercising alone or eating the injuring food without exercising, produces no symptoms. Such type of Urticaria can be diagnosed by having the patient exercise and then observing the symptoms that germinate. This method must be utilised with caution and only in such a circumstance with the appropriate resuscitative measures ready at hand. Exercise-induced anaphylaxis can be differentiated from cholinergic Urticaria by the hot water immersion test. In this test, the patient is immersed in water at 43 degrees Celsius (109.4 degrees Fahrenheit). Someone with exercise-induced anaphylaxis will not develop hives, while a person with cholinergic Urticaria will develop the characteristic small hives, especially on the neck and chest.
The immediate symptoms of this uncanny type of Urticaria are treated with antihistamines, epinephrine and airway support. Taking antihistamines prior to exercise may be effective. A medication referred to as ketotifen, is acknowledged to stabilise mast cells and prevents histamine release and has been effective in treating this hives disorder. Avoiding exercise or foods that cause the mentioned symptoms, is very important. In particular circumstances, tolerance can be brought on by regular exercise, but this must be under secure medical supervision.
Related conditions
AngioedemaAngioedema
Angioedema or Quincke's edema is the rapid swelling of the dermis, subcutaneous tissue, mucosa and submucosal tissues. It is very similar to urticaria, but urticaria, commonly known as hives, occurs in the upper dermis...
is similar to urticaria, but in angioedema, the swelling occurs in a lower layer of the dermis than it does in urticaria, as well as in the subcutis. This swelling can occur around the mouth, in the throat, in the abdomen, or in other locations. Urticaria and angioedema sometimes occur together in response to an allergen
Allergen
An allergen is any substance that can cause an allergy. In technical terms, an allergen is a non-parasitic antigen capable of stimulating a type-I hypersensitivity reaction in atopic individuals....
and is a concern in severe cases as angioedema of the throat can be fatal.
Cause
Many different substances in the environment may cause urticaria including: medications, food and physical agents.Medication
The anti-diabetic sulphonylurea glimepirideGlimepiride
Glimepiride is a medium-to-long acting sulfonylurea anti-diabetic drug. It is marketed as Amaryl by Sanofi-Aventis and GLIMY by Dr.Reddy's Labs...
(trade name Amaryl), in particular, has been documented to induce allergic reactions manifesting as urticaria. Other cases include dextroamphetamine
Dextroamphetamine
Dextroamphetamine is a psychostimulant drug which is known to produce increased wakefulness and focus as well as decreased fatigue and decreased appetite....
, aspirin
Aspirin
Aspirin , also known as acetylsalicylic acid , is a salicylate drug, often used as an analgesic to relieve minor aches and pains, as an antipyretic to reduce fever, and as an anti-inflammatory medication. It was discovered by Arthur Eichengrun, a chemist with the German company Bayer...
, ibuprofen
Ibuprofen
Ibuprofen is a nonsteroidal anti-inflammatory drug used for relief of symptoms of arthritis, fever, as an analgesic , especially where there is an inflammatory component, and dysmenorrhea....
, penicillin
Penicillin
Penicillin is a group of antibiotics derived from Penicillium fungi. They include penicillin G, procaine penicillin, benzathine penicillin, and penicillin V....
, clotrimazole
Clotrimazole
Clotrimazole is an antifungal medication commonly used in the treatment of fungal infections such as vaginal yeast infections, oral thrush, and ringworm...
, sulfonamide
Sulfonamide (medicine)
Sulfonamide or sulphonamide is the basis of several groups of drugs. The original antibacterial sulfonamides are synthetic antimicrobial agents that contain the sulfonamide group. Some sulfonamides are also devoid of antibacterial activity, e.g., the anticonvulsant sultiame...
s and anticonvulsant
Anticonvulsant
The anticonvulsants are a diverse group of pharmaceuticals used in the treatment of epileptic seizures. Anticonvulsants are also increasingly being used in the treatment of bipolar disorder, since many seem to act as mood stabilizers, and in the treatment of neuropathic pain. The goal of an...
s.
Diet
The most common food allergies in adults are shellfishShellfish
Shellfish is a culinary and fisheries term for exoskeleton-bearing aquatic invertebrates used as food, including various species of molluscs, crustaceans, and echinoderms. Although most kinds of shellfish are harvested from saltwater environments, some kinds are found only in freshwater...
and nut
Nut (fruit)
A nut is a hard-shelled fruit of some plants having an indehiscent seed. While a wide variety of dried seeds and fruits are called nuts in English, only a certain number of them are considered by biologists to be true nuts...
s. The most common food allergies in children are shellfish
Shellfish
Shellfish is a culinary and fisheries term for exoskeleton-bearing aquatic invertebrates used as food, including various species of molluscs, crustaceans, and echinoderms. Although most kinds of shellfish are harvested from saltwater environments, some kinds are found only in freshwater...
, nuts, peanut
Peanut
The peanut, or groundnut , is a species in the legume or "bean" family , so it is not a nut. The peanut was probably first cultivated in the valleys of Peru. It is an annual herbaceous plant growing tall...
s, eggs
Egg (food)
Eggs are laid by females of many different species, including birds, reptiles, amphibians, and fish, and have probably been eaten by mankind for millennia. Bird and reptile eggs consist of a protective eggshell, albumen , and vitellus , contained within various thin membranes...
, wheat
Wheat
Wheat is a cereal grain, originally from the Levant region of the Near East, but now cultivated worldwide. In 2007 world production of wheat was 607 million tons, making it the third most-produced cereal after maize and rice...
, and soy. It is uncommon for patients to have more than 2 true food allergies. A less common cause is exposure to certain bacteria, such as streptococcus
Streptococcus
Streptococcus is a genus of spherical Gram-positive bacteria belonging to the phylum Firmicutes and the lactic acid bacteria group. Cellular division occurs along a single axis in these bacteria, and thus they grow in chains or pairs, hence the name — from Greek στρεπτος streptos, meaning...
or possibly Helicobacter pylori
Helicobacter pylori
Helicobacter pylori , previously named Campylobacter pyloridis, is a Gram-negative, microaerophilic bacterium found in the stomach. It was identified in 1982 by Barry Marshall and Robin Warren, who found that it was present in patients with chronic gastritis and gastric ulcers, conditions that were...
.
Physical agents
A number of physical urticarias include- Aquagenic: Reaction to waterWaterWater is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...
(exceedingly rare) - CholinergicCholinergic urticariaCholinergic urticaria is a subcategory of physical urticaria that is a skin rash brought on by a hypersensitive reaction to body heat...
: Reaction to body heat, such as when exercisingExercise urticariaExercise urticaria is a form of urticaria that happens during or after exercise, e.g. jogging or running. Urticaria is an allergic reaction in the skin characterized by itching -- as well as possible rash, swelling or hives -- on the legs, arms, torso or neck...
or after a hot shower - Cold (Chronic cold urticariaChronic cold urticariaCold Urticaria is an allergy where hives or large red welts form on the skin after exposure to a cold stimulus. The welts are usually itchy and often the hands and feet will become itchy and swollen as well...
): Reaction to cold, such as ice, cold air or water - worse with sudden change in temperature - Delayed Pressure: Reaction to standing for long periods, bra-straps, elastic bands on undergarments, belts
- DermatographicDermatographic urticariaDermatographic urticaria is a skin disorder seen in 4–5% of the population and is one of the most common types of urticaria, in which the skin becomes raised and inflamed when stroked, scratched, rubbed, and sometimes even slapped.-Presentation:The symptoms are thought to be caused by mast cells in...
: Reaction when skin is scratched (very common) - Heat: Reaction to hot food or objects (rare)
- Solar: Reaction to direct sunlight (rare, though more common in those with fair skin)
- Vibration: Reaction to vibration (rare)
- AdrenergicAdrenergicAn adrenergic agent is a drug, or other substance, which has effects similar to, or the same as, epinephrine . Thus, it is a kind of sympathomimetic agent...
: Reaction to adrenaline / noradrenaline (extremely rare)
Other
Urticaria can be a complication and symptom of a parasitic infection as fascioliasisFascioliasis
Fasciolosis also known as Fascioliasis, Fasciolasis, distomatosis and liver rot, is an important helminth disease caused by two trematodes Fasciola hepatica and Fasciola gigantica. This disease belongs to the plant-borne trematode zoonoses. In Europe, the Americas and Oceania only F...
(Fasciola hepatica
Fasciola hepatica
Fasciola hepatica, also known as the common liver fluke or sheep liver fluke, is a parasitic flatworm of the class Trematoda, phylum Platyhelminthes that infects the livers of various mammals, including humans. The disease caused by the fluke is called fascioliasis . F...
) and ascariasis (Ascaris lumbricoides
Ascaris lumbricoides
Ascaris lumbricoides is the giant roundworm of humans, belonging to the phylum Nematoda. An ascarid nematode, it is responsible for the disease ascariasis in humans, and it is the largest and most common parasitic worm in humans. One-sixth of the human population is estimated to be infected by this...
).
The rash that develops from poison ivy
Poison ivy
Toxicodendron radicans, better known as poison ivy , is a poisonous North American plant that is well known for its production of urushiol, a clear liquid compound found within the sap of the plant that causes an itching rash in most people who touch it...
, poison oak
Poison oak
Poison oak may refer to* Toxicodendron diversilobum, grows on West Coast of North America* Toxicodendron pubescens, grows in the Eastern United Statesdamnnnnn tissss is terribleee...
, and poison sumac
Poison Sumac
Poison sumac is a woody shrub or small tree growing to 7 m tall. All parts of the plant contain a resin called urushiol that causes skin and mucous membrane irritation to humans...
contact is commonly mistaken for urticaria. This rash is caused by contact with urushiol
Urushiol
Urushiol is an oily organic allergen found in plants of the family Anacardiaceae, especially Toxicodendron spp. . It causes an allergic skin rash on contact, known as urushiol-induced contact dermatitis...
and results in a form of contact dermatitis
Contact dermatitis
Contact dermatitis is a term for a skin reaction resulting from exposure to allergens or irritants . Phototoxic dermatitis occurs when the allergen or irritant is activated by sunlight....
called Urushiol-induced contact dermatitis
Urushiol-induced contact dermatitis
Urushiol-induced contact dermatitis is the medical name given to allergic rashes produced by the oil urushiol, which is contained in various plants, including the plants of the genus Toxicodendron , other plants in the family Anacardiaceae Urushiol-induced contact dermatitis (also called...
. Urushiol is spread by contact, but can be washed off with a strong grease/oil dissolving detergent and cool water and rubbing ointments.
Pathophysiology
The skin lesions of urticarial disease are caused by an inflammatory reaction in the skin, causing leakage of capillaries in the dermisDermis
The dermis is a layer of skin between the epidermis and subcutaneous tissues, and is composed of two layers, the papillary and reticular dermis...
, and resulting in an edema
Edema
Edema or oedema ; both words from the Greek , oídēma "swelling"), formerly known as dropsy or hydropsy, is an abnormal accumulation of fluid beneath the skin or in one or more cavities of the body that produces swelling...
which persists until the interstitial fluid
Interstitial fluid
Interstitial fluid is a solution that bathes and surrounds the cells of multicellular animals. It is the main component of the extracellular fluid, which also includes plasma and transcellular fluid...
is absorbed into the surrounding cells.
Urticaria are caused by the release of histamine
Histamine
Histamine is an organic nitrogen compound involved in local immune responses as well as regulating physiological function in the gut and acting as a neurotransmitter. Histamine triggers the inflammatory response. As part of an immune response to foreign pathogens, histamine is produced by...
and other mediators of inflammation (cytokines) from cells in the skin. This process can be the result of an allergic or non-allergic reaction, differing in the eliciting mechanism of histamine release.
Allergic urticaria : Histamine and other pro-inflammatory substances are released from mast cells in the skin and tissues in response to the binding of allergen
Allergen
An allergen is any substance that can cause an allergy. In technical terms, an allergen is a non-parasitic antigen capable of stimulating a type-I hypersensitivity reaction in atopic individuals....
-bound IgE
IGE
IGE was one of the largest services company buying and selling virtual currencies and accounts for MMORPG. During its peak time, it had offices in Los Angeles, China , and headquarters & customer service centre in Hong Kong. IGE was one of the main monopoly in virtual economy services, also known...
antibodies to high affinity cell surface receptors. Basophils and other inflammatory cells are also seen to release histamine and other mediators, and are thought to play an important role, especially in chronic urticarial diseases.
Autoimmune urticaria : In the past decade, it has been noted that many cases of chronic idiopathic urticaria are the result of an autoimmune trigger. For example, roughly one third of patients with chronic urticaria spontaneously develop auto-antibodies directed at the receptor FcεRI located on skin mast cells. Chronic stimulation of this receptor leads to chronic hives. Patients often have other autoimmune conditions such as autoimmune thyroiditis
Autoimmune thyroiditis
Autoimmune thyroiditis is a form of thyroiditis associated with an autoimmune disease where the body treats the thyroid gland and sometimes the hormones it produces as foreign bodies, therefore rejecting and attacking both.-Treatment:...
.
Infections : Hive-like rashes commonly accompany viral illnesses, such as the common cold. They usually appear 3–5 days after the cold has started, and may even appear a few days after the cold has resolved.
Non-allergic urticaria : Mechanisms other than allergen-antibody interactions are known to cause histamine release from mast cells. Many drugs, for example morphine
Morphine
Morphine is a potent opiate analgesic medication and is considered to be the prototypical opioid. It was first isolated in 1804 by Friedrich Sertürner, first distributed by same in 1817, and first commercially sold by Merck in 1827, which at the time was a single small chemists' shop. It was more...
, can induce direct histamine release not involving any immunoglobulin molecule. Also, a diverse group of signaling substances called neuropeptides have been found to be involved in emotionally induced urticaria. Dominantly inherited cutaneous and neurocutaneous porphyrias (porphyria cutanea tarda
Porphyria cutanea tarda
Porphyria cutanea tarda is the most common subtype of porphyria. The disorder results from low levels of the enzyme responsible for the fifth step in heme production. Heme is a vital molecule for all of the body's organs...
, hereditary coproporphyria
Hereditary coproporphyria
Hereditary coproporphyria is a type of acute porphyria that is associated with a deficiency of the enzyme coproporphyrinogen III oxidase....
, variegate porphyria
Variegate porphyria
Variegate porphyria is an autosomal dominant porphyria that can have acute symptoms along with symptoms that affect the skin...
and erythropoietic protoporphyria
Erythropoietic protoporphyria
Erythropoietic protoporphyria is a relatively mild form of porphyria, although very painful, which arises from a deficiency in the enzyme ferrochelatase, leading to abnormally high levels of protoporphyrin in the tissue...
) have been associated with solar urticaria
Solar urticaria
Solar urticaria is a rare condition in which exposure to ultraviolet or UV radiation, or sometimes even visible light, induces a case of urticaria or hives that can appear in both covered and uncovered areas of the skin. It is classified as a type of physical urticaria. The classification of...
. The occurrence of drug-induced solar urticaria
Solar urticaria
Solar urticaria is a rare condition in which exposure to ultraviolet or UV radiation, or sometimes even visible light, induces a case of urticaria or hives that can appear in both covered and uncovered areas of the skin. It is classified as a type of physical urticaria. The classification of...
may be associated with porphyrias. This may be caused by IgG binding not IgE
IGE
IGE was one of the largest services company buying and selling virtual currencies and accounts for MMORPG. During its peak time, it had offices in Los Angeles, China , and headquarters & customer service centre in Hong Kong. IGE was one of the main monopoly in virtual economy services, also known...
.
Dietary histamine poisoning : This is termed scombroid food poisoning. Ingestion of free histamine released by bacterial decay in fish flesh may result in a rapid-onset allergic-type symptom complex which includes urticaria. However, the urticaria produced by scombroid is reported not to include wheals.
Stress and chronic idiopathic urticaria : Chronic idiopathic urticaria has been anecdotally linked to stress since the 1940s. There is a large body of evidence demonstrating an association between this condition and both poor emotional well-being and reduced health related quality of life
Quality of life
The term quality of life is used to evaluate the general well-being of individuals and societies. The term is used in a wide range of contexts, including the fields of international development, healthcare, and politics. Quality of life should not be confused with the concept of standard of...
. A link between stress and this condition has also been shown. A recent study involving the Department of Immunology at Derriford Hospital and the University of Plymouth has demonstrated an association between stressful life events (e.g. bereavement, divorce, etc.) and chronic idiopathic urticaria and also an association between posttraumatic stress and chronic idiopathic urticaria.
Management
Chronic urticaria can be difficult to treat. There are no guaranteed treatments or means of controlling attacks, and some sub-populations are treatment-resistant, with medications spontaneously losing their effectiveness and requiring new medications to control attacks. It can be difficult to determine appropriate medications since some, such as loratadineLoratadine
Loratadine is a second-generation H1 histamine antagonist drug used to treat allergies. Structurally, it is closely related to tricyclic antidepressants such as imipramine, and distantly related to the atypical antipsychotic quetiapine. It is marketed by Schering-Plough under several trade names...
, require a day or two to build up to effective levels and since the condition is intermittent and outbreaks typically clear up without any treatment.
Most treatment plans for urticaria involve being aware of one's triggers, but this can be difficult since there are several forms of urticaria and people often exhibit more than one type. Also, since symptoms are often idiopathic
Idiopathic
Idiopathic is an adjective used primarily in medicine meaning arising spontaneously or from an obscure or unknown cause. From Greek ἴδιος, idios + πάθος, pathos , it means approximately "a disease of its own kind". It is technically a term from nosology, the classification of disease...
(unknown reason) there might not be any clear trigger. If one's triggers can be identified then outbreaks can often be managed by limiting one's exposure to these situations.
Antihistamines
Drug treatment is typically in the form of antihistamineAntihistamine
An H1 antagonist is a histamine antagonist of the H1 receptor that serves to reduce or eliminate effects mediated by histamine, an endogenous chemical mediator released during allergic reactions...
s such as fexofenadine
Fexofenadine
Fexofenadine is an antihistamine drug used in the treatment of hayfever and similar allergy symptoms...
, diphenhydramine
Diphenhydramine
Diphenhydramine hydrochloride is a first-generation antihistamine possessing anticholinergic, antitussive, antiemetic, and sedative properties which is mainly used to treat allergies. Like most other first-generation antihistamines, the drug also has a powerful hypnotic effect, and for this reason...
, hydroxyzine
Hydroxyzine
Hydroxyzine is a first-generation antihistamine of the diphenylmethane and piperazine classes. It was first synthesized by Union Chimique Belge in 1956 and was marketed by Pfizer in the United States later the same year, and is still in widespread use today....
, cetirizine
Cetirizine
Cetirizine , a second-generation antihistamine, is a major metabolite of hydroxyzine, and a racemic selective H1 receptor inverse agonist used in the treatment of allergies, hay fever, angioedema, and urticaria.-Availability:...
and other H1 receptor
Histamine receptor
The histamine receptors are a class of G protein-coupled receptors with histamine as their endogenous ligand.There are four known histamine receptors:*H1 receptor*H2 receptor*H3 receptor*H4 receptor-Comparison:...
antagonists. These are taken on a regular basis to protective effect, lessening or halting attacks. Treatments such as stress management
Stress management
Stress management is the alteration of stress and especially chronic stress often for the purpose of improving everyday functioning.Stress produces numerous symptoms which vary according to persons, situations, and severity. These can include physical health decline as well as depression. According...
can sometimes lessen severity and occurrence. Additionally, methods similar to psychological pain management can be used to shift focus away from the discomfort and itchiness during an attack.
Other
Tricyclic antidepressantTricyclic antidepressant
Tricyclic antidepressants are heterocyclic chemical compounds used primarily as antidepressants. The TCAs were first discovered in the early 1950s and were subsequently introduced later in the decade; they are named after their chemical structure, which contains three rings of atoms...
s, such as doxepin
Doxepin
Doxepin is a psychotropic agent with tricyclic antidepressant and anxiolytic properties, known under many brand-names such as Aponal, the original preparation by Boehringer-Mannheim, now part of the Roche group; Adapine, Doxal , Deptran, Sinquan and Sinequan...
, also are often potent H1 and H2 antagonists and may have a role in therapy, although side effects limit their use. For very severe outbreaks, an oral corticosteroid
Corticosteroid
Corticosteroids are a class of steroid hormones that are produced in the adrenal cortex. Corticosteroids are involved in a wide range of physiologic systems such as stress response, immune response and regulation of inflammation, carbohydrate metabolism, protein catabolism, blood electrolyte...
such as Prednisone
Prednisone
Prednisone is a synthetic corticosteroid drug that is particularly effective as an immunosuppressant drug. It is used to treat certain inflammatory diseases and some types of cancer, but has significant adverse effects...
is sometimes prescribed. However this form of treatment is controversial because of the extensive side effects common with corticosteroids and as such is not a recommended long-term treatment option. For acute urticaria, some topical creams such as Hydrocortisone, Fluocinonide, Desonate can also be prescribed to relieve itching. To boost relief for severe anaphylactic urticaria, a dermatologist will also administer steroid shots intramuscularly.
As of 2008 an Australian company is performing clinical trial
Clinical trial
Clinical trials are a set of procedures in medical research and drug development that are conducted to allow safety and efficacy data to be collected for health interventions...
s with an analogue of alpha-melanocyte-stimulating hormone
Melanocyte-stimulating hormone
The melanocyte-stimulating hormones are a class of peptide hormones that are produced by cells in the intermediate lobe of the pituitary gland...
called afamelanotide
Afamelanotide
Afamelanotide developed at the University of Arizona is a synthetic analog of the naturally-occurring melanocortin peptide hormone alpha-melanocyte stimulating hormone that has been shown to induce skin pigmentation through melanogenesis and thereby subsequently reduce sun damage to UV exposed...
(formerly CUV1647) for the treatment of solar urticaria, a type of urticaria that develops in response to exposure to specific wavelengths of light.