Allergic rhinitis
Encyclopedia
Allergic rhinitis, also known as pollenosis or hay fever, is an allergic inflammation
of the nasal airways.
It occurs when an allergen
, such as pollen
, dust or animal dander (particles of shed skin and hair) is inhaled by an individual with a sensitized immune system
. In such individuals, the allergen triggers the production of the antibody
immunoglobulin E
(IgE), which binds to mast cells and basophils
containing histamine
.
IgE bound to mast cells are stimulated by pollen and dust, causing the release of inflammatory mediators such as histamine (and other chemicals). This usually causes sneezing, itchy and watery eyes, swelling and inflammation of the nasal passages, and an increase in mucus
production. Symptoms vary in severity between individuals. Very sensitive individuals can experience hives or other rash
es. Particulate matter in polluted air, and chemicals such as chlorine
and detergents, which can normally be tolerated, can greatly aggravate allergic rhinitis. The physician John Bostock
first described hay fever in 1819 as a disease.
include:
Allergic rhinitis may also be classified as Mild-Intermittent, Moderate-Severe intermittent, Mild-Persistent, and Moderate-Severe Persistent. Intermittent is when the symptoms occur <4 days per week or <4 consecutive weeks. Persistent is when symptoms occur >4 days/week and >4 consecutive weeks. The symptoms are considered mild with normal sleep, no impairment of daily activities, no impairment of work or school, and if symptoms are not troublesome. Severe symptoms result in sleep disturbance, impairment of daily activities, and impairment of school or work. .
(excess nasal secretion), itching, and nasal congestion and obstruction.
Characteristic physical findings include conjunctival swelling and erythema
, eyelid swelling, lower eyelid venous stasis, lateral crease on the nose, swollen nasal turbinates, and middle ear effusion.
Sufferers might also find that cross-reactivity
occurs. For example, someone allergic to birch pollen may also find that they have an allergic reaction to the skin of apples or potatoes. A clear sign of this is the occurrence of an itchy throat after eating an apple or sneezing when peeling potatoes or apples. This occurs because of similarities in the proteins of the pollen and the food. There are many cross-reacting substances.
Some disorders may be associated with allergies: Comorbidities
include eczema
, asthma
and depression
Allergic rhinitis triggered by the pollen
s of specific seasonal plants is commonly known as "hay fever", because it is most prevalent during hay
ing season. However, it is possible to suffer from hay fever throughout the year. The pollen which causes hay fever varies between individuals and from region to region; generally speaking, the tiny, hardly visible pollens of wind-pollinated
plant
s are the predominant cause. Pollens of insect-pollinated
plants are too large to remain airborne and pose no risk. Examples of plants commonly responsible for hay fever include:
Allergy testing may reveal the specific allergens an individual is sensitive to. Skin testing is the most common method of allergy testing. This may include intradermal, scratch, patch, or other tests. Less commonly, the suspected allergen is dissolved and dropped onto the lower eyelid as a means of testing for allergies. (This test should only be done by a physician, never the patient, since it can be harmful if done improperly). In some individuals who cannot undergo skin testing (as determined by the doctor), the RAST blood test may be helpful in determining specific allergen sensitivity.
s are the preferred treatment if medications are required with other options used only if these are not effective. Mite
proof covers, air filters, and withholding certain foods in childhood do not have evidence supporting their use.
s are effective and safe, and may be effective without oral antihistamines. They take several days to act and so need be taken continually for several weeks as their therapeutic effect builds up with time.
Systemic steroids such as prednisone
are effective at reducing nasal inflammation, but their use is limited by their short duration of effect and the side effects of prolonged steroid therapy.
s, decongestant
s, cromolyn, leukotriene receptor antagonists, and nonpharmacologic therapies such as nasal irrigation
.
Antihistamine drugs can have undesirable side-effects, most notably drowsiness. First generation antihistamine drugs such as diphenhydramine
cause drowsiness, but not second- and third-generation antihistamines such as cetirizine
and loratadine
.
Antihistamine drugs can be taken orally to control symptoms such as sneezing, rhinorrhea, itching and conjunctivitis. It is best to take the medication before exposure, especially for seasonal allergic rhinitis. Ophthalmic antihistamines (such as ketotifen
) are used for conjunctivitis; intranasal forms are used for sneezing, rhinorrhea and nasal pruritus.
Pseudoephedrine
is also indicated for vasomotor rhinitis. It is only used when nasal congestion is present and can be used with antihistamines. In the United States, oral decongestants containing pseudoephedrine must be purchased behind the pharmacy counter by law to combat the making of methamphetamine.
Topical decongestant
s: may also be helpful in reducing symptoms such as nasal congestion, but should not be used for long periods as stopping them after protracted use can lead to a rebound nasal congestion (Rhinitis medicamentosa
).
For nocturnal symptoms, intranasal corticosteroid
s can be combined with nightly oxymetazoline
, an adrenergic alpha-agonist, without risk of rhinitis medicamentosa
.
Inflammation
Inflammation is part of the complex biological response of vascular tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. Inflammation is a protective attempt by the organism to remove the injurious stimuli and to initiate the healing process...
of the nasal airways.
It occurs when 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....
, such as pollen
Pollen
Pollen is a fine to coarse powder containing the microgametophytes of seed plants, which produce the male gametes . Pollen grains have a hard coat that protects the sperm cells during the process of their movement from the stamens to the pistil of flowering plants or from the male cone to the...
, dust or animal dander (particles of shed skin and hair) is inhaled by an individual with a sensitized immune system
Immune system
An immune system is a system of biological structures and processes within an organism that protects against disease by identifying and killing pathogens and tumor cells. It detects a wide variety of agents, from viruses to parasitic worms, and needs to distinguish them from the organism's own...
. In such individuals, the allergen triggers the production of the antibody
Antibody
An antibody, also known as an immunoglobulin, is a large Y-shaped protein used by the immune system to identify and neutralize foreign objects such as bacteria and viruses. The antibody recognizes a unique part of the foreign target, termed an antigen...
immunoglobulin E
Immunoglobulin E
Immunoglobulin E is a class of antibody that has been found only in mammals. IgE is a monomeric antibody with 4 Ig-like domains...
(IgE), which binds to mast cells and basophils
Basophil granulocyte
Basophil granulocytes, sometimes referred to as basophils, are the least common of the granulocytes, representing about 0.01% to 0.3% of circulating white blood cells....
containing 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...
.
IgE bound to mast cells are stimulated by pollen and dust, causing the release of inflammatory mediators such as histamine (and other chemicals). This usually causes sneezing, itchy and watery eyes, swelling and inflammation of the nasal passages, and an increase in mucus
Mucus
In vertebrates, mucus is a slippery secretion produced by, and covering, mucous membranes. Mucous fluid is typically produced from mucous cells found in mucous glands. Mucous cells secrete products that are rich in glycoproteins and water. Mucous fluid may also originate from mixed glands, which...
production. Symptoms vary in severity between individuals. Very sensitive individuals can experience hives or other rash
Rash
A rash is a change of the skin which affects its color, appearance or texture. A rash may be localized in one part of the body, or affect all the skin. Rashes may cause the skin to change color, itch, become warm, bumpy, chapped, dry, cracked or blistered, swell and may be painful. The causes, and...
es. Particulate matter in polluted air, and chemicals such as chlorine
Chlorine
Chlorine is the chemical element with atomic number 17 and symbol Cl. It is the second lightest halogen, found in the periodic table in group 17. The element forms diatomic molecules under standard conditions, called dichlorine...
and detergents, which can normally be tolerated, can greatly aggravate allergic rhinitis. The physician John Bostock
John Bostock (physician)
John Bostock MD FRS was a physician, scientist and geologist from Liverpool. He spent some time at New College at Hackney where he attended Priestley's lectures on chemistry and natural philosophy, before graduating in Medicine at the University of Edinburgh and practising medicine in Liverpool,...
first described hay fever in 1819 as a disease.
Classification
The two categories of allergic rhinitisRhinitis
Rhinitis , commonly known as a stuffy nose, is the medical term describing irritation and inflammation of some internal areas of the nose. The primary symptom of rhinitis is nasal dripping. It is caused by chronic or acute inflammation of the mucous membrane of the nose due to viruses, bacteria or...
include:
- Seasonal—occurs particularly during pollen seasons. Seasonal allergic rhinitis does not usually develop until after 6 years of age.
- Perennial—occurs throughout the year. This type of allergic rhinitis is commonly seen in younger children.
Allergic rhinitis may also be classified as Mild-Intermittent, Moderate-Severe intermittent, Mild-Persistent, and Moderate-Severe Persistent. Intermittent is when the symptoms occur <4 days per week or <4 consecutive weeks. Persistent is when symptoms occur >4 days/week and >4 consecutive weeks. The symptoms are considered mild with normal sleep, no impairment of daily activities, no impairment of work or school, and if symptoms are not troublesome. Severe symptoms result in sleep disturbance, impairment of daily activities, and impairment of school or work. .
Signs and symptoms
The characteristic symptoms of allergic rhinitis are: rhinorrheaRhinorrhea
Rhinorrhea or rhinorrhoea is a condition where the nasal cavity is filled with a significant amount of mucous fluid. The condition, commonly known as "runny nose", occurs relatively frequently and is not usually considered dangerous. Rhinorrhea is a common symptom of allergies or certain diseases,...
(excess nasal secretion), itching, and nasal congestion and obstruction.
Characteristic physical findings include conjunctival swelling and erythema
Erythema
Erythema is redness of the skin, caused by hyperemia of the capillaries in the lower layers of the skin. It occurs with any skin injury, infection, or inflammation...
, eyelid swelling, lower eyelid venous stasis, lateral crease on the nose, swollen nasal turbinates, and middle ear effusion.
Sufferers might also find that cross-reactivity
Oral allergy syndrome
Oral allergy syndrome or OAS is a type of food allergy classified by a cluster of allergic reactions in the mouth in response to eating certain fruits, nuts, and vegetables that typically develops in adult hay fever sufferers....
occurs. For example, someone allergic to birch pollen may also find that they have an allergic reaction to the skin of apples or potatoes. A clear sign of this is the occurrence of an itchy throat after eating an apple or sneezing when peeling potatoes or apples. This occurs because of similarities in the proteins of the pollen and the food. There are many cross-reacting substances.
Some disorders may be associated with allergies: Comorbidities
Comorbidity
In medicine, comorbidity is either the presence of one or more disorders in addition to a primary disease or disorder, or the effect of such additional disorders or diseases.- In medicine :...
include eczema
Eczema
Eczema is a form of dermatitis, or inflammation of the epidermis . In England, an estimated 5.7 million or about one in every nine people have been diagnosed with the disease by a clinician at some point in their lives.The term eczema is broadly applied to a range of persistent skin conditions...
, asthma
Asthma
Asthma is the common chronic inflammatory disease of the airways characterized by variable and recurring symptoms, reversible airflow obstruction, and bronchospasm. Symptoms include wheezing, coughing, chest tightness, and shortness of breath...
and depression
Clinical depression
Major depressive disorder is a mental disorder characterized by an all-encompassing low mood accompanied by low self-esteem, and by loss of interest or pleasure in normally enjoyable activities...
Cause
Allergies are common. Heredity and environmental exposures may contribute to a predisposition to allergies. It is roughly estimated that one in three people have an active allergy at any given time and at least three in four people develop an allergic reaction at least once in their lives.Allergic rhinitis triggered by the pollen
Pollen
Pollen is a fine to coarse powder containing the microgametophytes of seed plants, which produce the male gametes . Pollen grains have a hard coat that protects the sperm cells during the process of their movement from the stamens to the pistil of flowering plants or from the male cone to the...
s of specific seasonal plants is commonly known as "hay fever", because it is most prevalent during hay
Hay
Hay is grass, legumes or other herbaceous plants that have been cut, dried, and stored for use as animal fodder, particularly for grazing livestock such as cattle, horses, goats, and sheep. Hay is also fed to pets such as rabbits and guinea pigs...
ing season. However, it is possible to suffer from hay fever throughout the year. The pollen which causes hay fever varies between individuals and from region to region; generally speaking, the tiny, hardly visible pollens of wind-pollinated
Anemophily
Anemophily or wind pollination is a form of pollination whereby pollen is distributed by wind. Anemophilous plants may be either gymnosperms or angiosperms ....
plant
Plant
Plants are living organisms belonging to the kingdom Plantae. Precise definitions of the kingdom vary, but as the term is used here, plants include familiar organisms such as trees, flowers, herbs, bushes, grasses, vines, ferns, mosses, and green algae. The group is also called green plants or...
s are the predominant cause. Pollens of insect-pollinated
Entomophily
Entomophily is a form of pollination whereby pollen is distributed by insects. Several insect are reported to be responsible for the pollination of many plant species, particularly bees, Lepidoptera , wasps, flies, ants and beetles. Some plant species co-evolved with a particular pollinator, such...
plants are too large to remain airborne and pose no risk. Examples of plants commonly responsible for hay fever include:
- Trees: such as pine, birch (Betula), alder (Alnus), cedar, hazel, hornbeam (Carpinus), horse chestnut (AesculusAesculusThe genus Aesculus comprises 13-19 species of woody trees and shrubs native to the temperate northern hemisphere, with 6 species native to North America and 7-13 species native to Eurasia; there are also several hybrids. Species are deciduous or evergreen...
), willow (Salix), poplarPoplarPopulus is a genus of 25–35 species of deciduous flowering plants in the family Salicaceae, native to most of the Northern Hemisphere. English names variously applied to different species include poplar , aspen, and cottonwood....
, plane (PlatanusPlatanusPlatanus is a small genus of trees native to the Northern Hemisphere. They are the sole living members of the family Platanaceae....
), linden/lime (TiliaTiliaTilia is a genus of about 30 species of trees native throughout most of the temperate Northern Hemisphere. The greatest species diversity is found in Asia, and the genus also occurs in Europe and eastern North America, but not western North America...
) and olive (OleaOleaOlea is a genus of about 40 species in the family Oleaceae, native to warm temperate and tropical regions of southern Europe, Africa, southern Asia and Australasia. They are evergreen trees and shrubs, with small, opposite, entire leaves...
). In northern latitudes birch is considered to be the most important allergenic tree pollen, with an estimated 15–20% of hay fever sufferers sensitive to birch pollen grains. Olive pollen is most predominant in Mediterranean regions. Hay fever in Japan is caused primarily by sugi (Cryptomeria japonica) and hinoki (Chamaecyparis obtusa) tree pollen. - Grasses (Family PoaceaePoaceaeThe Poaceae is a large and nearly ubiquitous family of flowering plants. Members of this family are commonly called grasses, although the term "grass" is also applied to plants that are not in the Poaceae lineage, including the rushes and sedges...
): especially ryegrassRyegrassRyegrass is a genus of nine species of tufted grasses in the Pooideae subfamily of the Poaceae family. Also called tares , these plants are native to Europe, Asia and northern Africa, but are...
(Lolium sp.) and timothyTimothy-grassTimothy-grass , is an abundant perennial grass native to most of Europe except for the Mediterranean region. It grows to 50–150 cm tall, with leaves up to 45 cm long and 1 cm broad. The flowerhead is 7–15 cm long and 8–10 mm broad, with densely packed spikelets...
(Phleum pratense). An estimated 90% of hay fever sufferers are allergic to grass pollen. - Weeds: ragweedRagweedRagweeds are flowering plants in the genus Ambrosia in the sunflower family Asteraceae. Common names include bitterweeds and bloodweeds....
(Ambrosia), plantain (PlantagoPlantagoPlantago is a genus of about 200 species of small, inconspicuous plants commonly called plantains. They share this name with the very dissimilar plantain, a kind of banana. Most are herbaceous plants, though a few are subshrubs growing to 60 cm tall. The leaves are sessile, but have a narrow...
), nettleNettleNettles constitute between 24 and 39 species of flowering plants of the genus Urtica in the family Urticaceae, with a cosmopolitan though mainly temperate distribution. They are mostly herbaceous perennial plants, but some are annual and a few are shrubby...
/parietaria (UrticaceaeUrticaceaeUrticaceae, or the nettle family, is a family of flowering plants. The family name comes from the genus Urtica . Urticaceae includes a number of well-known and useful plants, including the aforementioned nettles, Ramie , māmaki , and ajlai .The family includes approximately 2600 species, grouped...
), mugwort (Artemisia), Fat henFat HenFat hen or fat-hen may refer to:* Hen and chicks, common name for a group of small succulent flowering plants native to Europe and northern Africa* Fat Hen, common name for Aristolochia rotunda , a perennial herb native to Southern Europe...
(ChenopodiumChenopodiumChenopodium is a genus of about 150 species of perennial or annual herbaceous flowering plants known as the goosefoots, which occur almost anywhere in the world. It is placed in the family Amaranthaceae in the APG II system; older classifications separate it and its relatives as Chenopodiaceae, but...
) and sorrelSorrelCommon sorrel or garden sorrel , often simply called sorrel, is a perennial herb that is cultivated as a garden herb or leaf vegetable...
/dock (RumexRumexThe docks and sorrels, genus Rumex L., are a genus of about 200 species of annual, biennial and perennial herbs in the buckwheat family Polygonaceae....
)
Allergy testing may reveal the specific allergens an individual is sensitive to. Skin testing is the most common method of allergy testing. This may include intradermal, scratch, patch, or other tests. Less commonly, the suspected allergen is dissolved and dropped onto the lower eyelid as a means of testing for allergies. (This test should only be done by a physician, never the patient, since it can be harmful if done improperly). In some individuals who cannot undergo skin testing (as determined by the doctor), the RAST blood test may be helpful in determining specific allergen sensitivity.
Management
The goal of rhinitis treatment is to prevent or reduce the symptoms caused by the inflammation of affected tissues. Measures which are effective include avoiding the allergen. Intranasal corticosteroidCorticosteroid
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...
s are the preferred treatment if medications are required with other options used only if these are not effective. Mite
Mite
Mites, along with ticks, are small arthropods belonging to the subclass Acari and the class Arachnida. The scientific discipline devoted to the study of ticks and mites is called acarology.-Diversity and systematics:...
proof covers, air filters, and withholding certain foods in childhood do not have evidence supporting their use.
Steroids
Intranasal corticosteroids are used to control symptoms associated with sneezing, rhinorrhea, itching and nasal congestion. It is an excellent choice for perennial rhinitis. Steroid nasal sprayNasal spray
Nasal sprays come in a variety of forms. Medicated such as Astelin, Afrin and Nasonex and natural such as Sinusoothe and Sterimar. Although delivery methods vary, most nasal sprays function by instilling a fine mist into the nostril by action of a hand-operated pump mechanism.-Antihistamine nasal...
s are effective and safe, and may be effective without oral antihistamines. They take several days to act and so need be taken continually for several weeks as their therapeutic effect builds up with time.
Systemic steroids 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...
are effective at reducing nasal inflammation, but their use is limited by their short duration of effect and the side effects of prolonged steroid therapy.
Other
Other measures that may be used second line include: 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, decongestant
Decongestant
A decongestant or nasal decongestant is a type of drug that is used to relieve nasal congestion.-Pharmacology:The vast majority of decongestants act via enhancing norepinephrine and epinephrine or adrenergic activity by stimulating the α-adrenergic receptors...
s, cromolyn, leukotriene receptor antagonists, and nonpharmacologic therapies such as nasal irrigation
Nasal irrigation
Nasal irrigation or nasal lavage or nose douche is the personal hygiene practice in which the nasal cavity is washed to flush out excess mucus and debris from the nose and sinuses. The practice is well-tolerated and beneficial with only minor side effects...
.
Antihistamine drugs can have undesirable side-effects, most notably drowsiness. First generation antihistamine drugs such as 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...
cause drowsiness, but not second- and third-generation antihistamines such as 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 loratadine
Loratadine
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...
.
Antihistamine drugs can be taken orally to control symptoms such as sneezing, rhinorrhea, itching and conjunctivitis. It is best to take the medication before exposure, especially for seasonal allergic rhinitis. Ophthalmic antihistamines (such as ketotifen
Ketotifen
Ketotifen is a second-generation H1-antihistamine and mast cell stabilizer. It is most commonly sold in as a salt of Fumaric Acid, Ketotifen fumarate, and is available in two forms. In its ophthalmic form, it is used to treat allergic conjunctivitis, or the itchy red eyes caused by allergies. In...
) are used for conjunctivitis; intranasal forms are used for sneezing, rhinorrhea and nasal pruritus.
Pseudoephedrine
Pseudoephedrine
Pseudoephedrine is a sympathomimetic drug of the phenethylamine and amphetamine chemical classes. It is used as a nasal/sinus decongestant and stimulant, or as a wakefulness-promoting agent....
is also indicated for vasomotor rhinitis. It is only used when nasal congestion is present and can be used with antihistamines. In the United States, oral decongestants containing pseudoephedrine must be purchased behind the pharmacy counter by law to combat the making of methamphetamine.
Topical decongestant
Topical decongestant
Topical decongestants are decongestants applied directly to the nasal cavity. By applying them directly to the site of action, topical decongestants relieve nasal congestion while reducing the side effects associated with systemically-acting decongestants, such as high blood pressure...
s: may also be helpful in reducing symptoms such as nasal congestion, but should not be used for long periods as stopping them after protracted use can lead to a rebound nasal congestion (Rhinitis medicamentosa
Rhinitis medicamentosa
Rhinitis medicamentosa is a condition of rebound nasal congestion brought on by extended use of topical decongestants that work by constricting blood vessels in the lining of the nose.-Presentation:This condition typically occurs after 5 to 7 days of use of such medications...
).
For nocturnal symptoms, intranasal 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...
s can be combined with nightly oxymetazoline
Oxymetazoline
Oxymetazoline is a selective alpha-1 agonist and partial alpha-2 agonist topical decongestant, used in the form of Oxymetazoline hydrochloride, in products such as Afrin, Dristan, Nasivin, Logicin, Vicks Sinex, Visine L.R., Sudafed OM, and Zicam. It was developed from Xylometazoline at E.Merck...
, an adrenergic alpha-agonist, without risk of rhinitis medicamentosa
Rhinitis medicamentosa
Rhinitis medicamentosa is a condition of rebound nasal congestion brought on by extended use of topical decongestants that work by constricting blood vessels in the lining of the nose.-Presentation:This condition typically occurs after 5 to 7 days of use of such medications...
.