Skin infection
Encyclopedia
A skin infection is an infection
of the skin
. Infection of the skin is distinguished from dermatitis
, which is inflammation
of the skin, but a skin infection can result in skin inflammation. Skin inflammation due to skin infection is called infective dermatitis.
of the skin, hair, and/or nails.
: Annelida, Arthropoda, Bryozoa
, Chordata, Cnidaria
, Cyanobacteria, Echinodermata, Nemathelminthes, Platyhelminthes, and Protozoa
.
es–DNA
and RNA
types–both of which are obligatory
intracellular
parasites.
Infection
An infection is the colonization of a host organism by parasite species. Infecting parasites seek to use the host's resources to reproduce, often resulting in disease...
of the skin
Skin
-Dermis:The dermis is the layer of skin beneath the epidermis that consists of connective tissue and cushions the body from stress and strain. The dermis is tightly connected to the epidermis by a basement membrane. It also harbors many Mechanoreceptors that provide the sense of touch and heat...
. Infection of the skin is distinguished from dermatitis
Dermatitis
-Etymology:Dermatitis derives from Greek derma "skin" + -itis "inflammation" and genetic disorder.-Terminology:There are several different types of dermatitis. The different kinds usually have in common an allergic reaction to specific allergens. The term may describe eczema, which is also called...
, which is inflammation
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 skin, but a skin infection can result in skin inflammation. Skin inflammation due to skin infection is called infective dermatitis.
Bacterial
Bacterial skin infections include:- ImpetigoImpetigoImpetigo is a highly contagious bacterial skin infection most common among pre-school children. People who play close contact sports such as rugby, American football and wrestling are also susceptible, regardless of age. Impetigo is not as common in adults. The name derives from the Latin impetere...
is a highly contagious bacteriaBacteriaBacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...
l skinHuman skinThe human skin is the outer covering of the body. In humans, it is the largest organ of the integumentary system. The skin has multiple layers of ectodermal tissue and guards the underlying muscles, bones, ligaments and internal organs. Human skin is similar to that of most other mammals,...
infectionInfectionAn infection is the colonization of a host organism by parasite species. Infecting parasites seek to use the host's resources to reproduce, often resulting in disease...
most common among pre-school children. It is primarily caused by Staphylococcus aureusStaphylococcus aureusStaphylococcus aureus is a facultative anaerobic Gram-positive coccal bacterium. It is frequently found as part of the normal skin flora on the skin and nasal passages. It is estimated that 20% of the human population are long-term carriers of S. aureus. S. aureus is the most common species of...
, and sometimes by Streptococcus pyogenesStreptococcus pyogenesStreptococcus pyogenes is a spherical, Gram-positive bacterium that is the cause of group A streptococcal infections. S. pyogenes displays streptococcal group A antigen on its cell wall. S...
. - ErysipelasErysipelasErysipelas is an acute streptococcus bacterial infection of the deep epidermis with lymphatic spread.-Risk factors:...
is an acute streptococcusStreptococcusStreptococcus 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...
bacteriaBacteriaBacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...
l infection of the deep epidermis with lymphatic spread. - CellulitisCellulitisCellulitis is a diffuse inflammation of connective tissue with severe inflammation of dermal and subcutaneous layers of the skin. Cellulitis can be caused by normal skin flora or by exogenous bacteria, and often occurs where the skin has previously been broken: cracks in the skin, cuts, blisters,...
is a diffuse inflammationInflammationInflammation 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 connective tissueConnective tissue"Connective tissue" is a fibrous tissue. It is one of the four traditional classes of tissues . Connective Tissue is found throughout the body.In fact the whole framework of the skeleton and the different specialized connective tissues from the crown of the head to the toes determine the form of...
with severe inflammation of dermal and subcutaneous layers of the skinSkin-Dermis:The dermis is the layer of skin beneath the epidermis that consists of connective tissue and cushions the body from stress and strain. The dermis is tightly connected to the epidermis by a basement membrane. It also harbors many Mechanoreceptors that provide the sense of touch and heat...
. Cellulitis can be caused by normal skin floraSkin floraThe skin flora are the microorganisms which reside on the skin. Most research has been upon those that reside upon the 2 square metres of human skin. Many of them are bacteria of which there are around 1000 species upon human skin from 19 phyla. The total number of bacteria on an average human has...
or by exogenous bacteriaExogenous bacteriaExogenous bacteria are bacteria introduced to closed biological systems from the external world. They exist in water, earth, and the air. Examples are cholera, Legionella, salmonella, rickettsia, mycobacterium, and bacillus anthracis. Endogenous bacteria are part of our normal internal flora....
, and often occurs where the skin has previously been broken: cracks in the skin, cuts, blisterBlisterA blister is a small pocket of fluid within the upper layers of the skin, typically caused by forceful rubbing , burning, freezing, chemical exposure or infection. Most blisters are filled with a clear fluid called serum or plasma...
s, burnsBurn (injury)A burn is a type of injury to flesh caused by heat, electricity, chemicals, light, radiation or friction. Most burns affect only the skin . Rarely, deeper tissues, such as muscle, bone, and blood vessels can also be injured...
, insect biteInsect biteInsect bites and stings occur when an insect is agitated and seeks to defend itself through its natural defense mechanisms, or when an insect seeks to feed off the bitten person. Some insects inject formic acid, which can cause an immediate skin reaction often resulting in redness and swelling in...
s, surgical wounds, intravenous drug injectionDrug injectionIn substance dependence and recreational drug use, drug injection is a method of introducing a drug into the body with a hollow needle and a syringe which is pierced through the skin into the body...
or sites of intravenous catheterCatheterIn medicine, a catheter is a tube that can be inserted into a body cavity, duct, or vessel. Catheters thereby allow drainage, administration of fluids or gases, or access by surgical instruments. The process of inserting a catheter is catheterization...
insertion. Skin on the face or lower legs is most commonly affected by this infection, though cellulitis can occur on any part of the body.
Fungal
Fungal skin infections may present as either a superficial or deep infectionInfection
An infection is the colonization of a host organism by parasite species. Infecting parasites seek to use the host's resources to reproduce, often resulting in disease...
of the skin, hair, and/or nails.
Parasitic infestations, stings, and bites
Parasitic infestations, stings, and bites in humans are caused by several groups of organisms belonging to the following phylaPhylum
In biology, a phylum The term was coined by Georges Cuvier from Greek φῦλον phylon, "race, stock," related to φυλή phyle, "tribe, clan." is a taxonomic rank below kingdom and above class. "Phylum" is equivalent to the botanical term division....
: Annelida, Arthropoda, Bryozoa
Bryozoa
The Bryozoa, also known as Ectoprocta or commonly as moss animals, are a phylum of aquatic invertebrate animals. Typically about long, they are filter feeders that sieve food particles out of the water using a retractable lophophore, a "crown" of tentacles lined with cilia...
, Chordata, Cnidaria
Cnidaria
Cnidaria is a phylum containing over 9,000 species of animals found exclusively in aquatic and mostly marine environments. Their distinguishing feature is cnidocytes, specialized cells that they use mainly for capturing prey. Their bodies consist of mesoglea, a non-living jelly-like substance,...
, Cyanobacteria, Echinodermata, Nemathelminthes, Platyhelminthes, and Protozoa
Protozoa
Protozoa are a diverse group of single-cells eukaryotic organisms, many of which are motile. Throughout history, protozoa have been defined as single-cell protists with animal-like behavior, e.g., movement...
.
Viral
Virus-related cutaneous conditions are caused by two main groups of virusVirus
A virus is a small infectious agent that can replicate only inside the living cells of organisms. Viruses infect all types of organisms, from animals and plants to bacteria and archaea...
es–DNA
DNA virus
A DNA virus is a virus that has DNA as its genetic material and replicates using a DNA-dependent DNA polymerase. The nucleic acid is usually double-stranded DNA but may also be single-stranded DNA . DNA viruses belong to either Group I or Group II of the Baltimore classification system for viruses...
and RNA
RNA virus
An RNA virus is a virus that has RNA as its genetic material. This nucleic acid is usually single-stranded RNA but may be double-stranded RNA...
types–both of which are obligatory
Obligation
An obligation is a requirement to take some course of action, whether legal or moral. There are also obligations in other normative contexts, such as obligations of etiquette, social obligations, and possibly...
intracellular
Intracellular
Not to be confused with intercellular, meaning "between cells".In cell biology, molecular biology and related fields, the word intracellular means "inside the cell".It is used in contrast to extracellular...
parasites.