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dermatitis

dermatitis

definition : dermatitis

Dermatitis, also known as eczema, is a group of diseases that results in inflammation of the skin. These diseases are characterized by itchiness, red skin, and a rash. The exact cause of dermatitis is often unclear. The steroid creams should generally be of mid- to high strength and used for less than two weeks at a time as side effects can occur. Antibiotics may be required if there are signs of skin infection. Antihistamines may help with sleep and to decrease nighttime scratching. Allergic contact dermatitis affects about 7% of people at some point in time. Irritant contact dermatitis is common, especially among people who do certain jobs; exact rates are unclear.

==Signs and symptoms==

Dermatitis symptoms vary with all different forms of the condition. They range from skin rashes to bumpy rashes or including blisters. Although every type of dermatitis has different symptoms, there are certain signs that are common for all of them, including redness of the skin, swelling, itching and skin lesions with sometimes oozing and scarring. Also, the area of the skin on which the symptoms appear tends to be different with every type of dermatitis, whether on the neck, wrist, forearm, thigh or ankle. Although the location may vary, the primary symptom of this condition is itchy skin. More rarely, it may appear on the genital area, such as the vulva or scrotum. Symptoms of this type of dermatitis may be very intense and may come and go. Irritant contact dermatitis is usually more painful than itchy.

Although the symptoms of atopic dermatitis vary from person to person, the most common symptoms are dry, itchy, red skin. Typical affected skin areas include the folds of the arms, the back of the knees, wrists, face and hands. Perioral dermatitis refers to a red bumpy rash around the mouth.

Dermatitis herpetiformis symptoms include itching, stinging and a burning sensation. Papules and vesicles are commonly present. The small red bumps experienced in this type of dermatitis are usually about 1 cm in size, red in color and may be found symmetrically grouped or distributed on the upper or lower back, buttocks, elbows, knees, neck, shoulders, and scalp. Less frequently, the rash may appear inside the mouth or near the hairline.

The symptoms of seborrheic dermatitis, on the other hand, tend to appear gradually, from dry or greasy scaling of the scalp (dandruff) to scaling of facial areas, sometimes with itching, but without hair loss. In newborns, the condition causes a thick and yellowish scalp rash, often accompanied by a diaper rash. In severe cases, symptoms may appear along the hairline, behind the ears, on the eyebrows, on the bridge of the nose, around the nose, on the chest, and on the upper back. File:Eczema.png|Dermatitis File:Eczema-arms.jpg|More severe dermatitis File:Eczema.jpg|A patch of dermatitis that has been scratched File:PLJohnson Complex Eczema.jpg|Complex dermatitis

==Cause== The cause of dermatitis is unknown but is presumed to be a combination of genetic and environmental factors. The hypothesis states that exposure to bacteria and other immune system modulators is important during development, and missing out on this exposure increases risk for asthma and allergy.

While it has been suggested that eczema may sometimes be an allergic reaction to the excrement from house dust mites, with up to 5% of people showing antibodies to the mites, the overall role this plays awaits further corroboration.

===Genetic=== A number of genes have been associated with eczema, one of which is filaggrin.

Eczema occurs about three times more frequently in individuals with celiac disease and about two times more frequently in relatives of those with celiac disease, potentially indicating a genetic link between the conditions. ==Pathophysiology== All eczemas are characterized by spongiosis which allows inflammatory mediators to accumulate. Different dendritic cells subtypes, such as Langerhans cells, inflammatory dendritic epidermal cells and plasmacytoid dendritic cells have a role to play.

==Diagnosis== Diagnosis of eczema is based mostly on the history and physical examination. Those with eczema may be especially prone to misdiagnosis of food allergies.

Patch tests are used in the diagnosis of allergic contact dermatitis.

===Classification=== The term "eczema" refers to a set of clinical characteristics. Classification of the underlying diseases has been haphazard with numerous different classification systems, and many synonyms being used to describe the same condition.

A type of dermatitis may be described by location (e.g., hand eczema), by specific appearance (eczema craquele or discoid), or by possible cause (varicose eczema). Further adding to the confusion, many sources use the term eczema interchangeably for the most common type: atopic dermatitis.

The European Academy of Allergology and Clinical Immunology (EAACI) published a position paper in 2001, which simplifies the nomenclature of allergy-related diseases, including atopic and allergic contact eczemas. Non-allergic eczemas are not affected by this proposal.

===Terminology=== There are several types of dermatitis including atopic dermatitis, contact dermatitis, stasis dermatitis, and seborrheic eczema. Atopic dermatitis is also known as atopic eczema.

===Common types=== Diagnosis of types may be indicated by codes defined according to International Statistical Classification of Diseases and Related Health Problems (ICD).

====Atopic==== Atopic dermatitis is an allergic disease believed to have a hereditary component and often runs in families whose members have asthma. Itchy rash is particularly noticeable on head and scalp, neck, inside of elbows, behind knees, and buttocks. It is very common in developed countries, and rising. Irritant contact dermatitis is sometimes misdiagnosed as atopic dermatitis.

====Contact==== Contact dermatitis is of two types: allergic (resulting from a delayed reaction to an allergen, such as poison ivy, nickel, or Balsam of Peru), and irritant (resulting from direct reaction to a detergent, such as sodium lauryl sulfate, for example).

Some substances act both as allergen and irritant (wet cement, for example). Other substances cause a problem after sunlight exposure, bringing on phototoxic dermatitis. About three quarters of cases of contact eczema are of the irritant type, which is the most common occupational skin disease. Contact eczema is curable, provided the offending substance can be avoided and its traces removed from one's environment. (ICD-10 L23; L24; L56.1; L56.0)

====Seborrhoeic==== Seborrhoeic dermatitis or seborrheic dermatitis ("cradle cap" in infants) is a condition sometimes classified as a form of eczema that is closely related to dandruff. It causes dry or greasy peeling of the scalp, eyebrows, and face, and sometimes trunk. In newborns it causes a thick, yellow, crusty scalp rash called cradle cap, which seems related to lack of biotin and is often curable. (ICD-10 L21; L21.0)

===Less common types=== ====Dyshidrosis==== Dyshidrosis (dyshidrotic eczema, pompholyx, vesicular palmoplantar dermatitis) only occurs on palms, soles, and sides of fingers and toes. Tiny opaque bumps called vesicles, thickening, and cracks are accompanied by itching, which gets worse at night. A common type of hand eczema, it worsens in warm weather. (ICD-10 L30.1)

====Discoid==== Discoid eczema (nummular eczema, exudative eczema, microbial eczema) is characterized by round spots of oozing or dry rash, with clear boundaries, often on lower legs. It is usually worse in winter. Cause is unknown, and the condition tends to come and go. (ICD-10 L30.0)

====Venous==== Venous eczema (gravitational eczema, stasis dermatitis, varicose eczema) occurs in people with impaired circulation, varicose veins, and edema, and is particularly common in the ankle area of people over 50. There is redness, scaling, darkening of the skin, and itching. The disorder predisposes to leg ulcers. (ICD-10 I83.1)

====Herpetiformis==== Dermatitis herpetiformis (Duhring's disease) causes intensely itchy and typically symmetrical rash on arms, thighs, knees, and back. It is directly related to celiac disease, can often be put into remission with appropriate diet, and tends to get worse at night. (ICD-10 L13.0)

====Neurodermatitis==== Neurodermatitis (lichen simplex chronicus, localized scratch dermatitis) is an itchy area of thickened, pigmented eczema patch that results from habitual rubbing and scratching. Usually there is only one spot. Often curable through behavior modification and anti-inflammatory medication. Prurigo nodularis is a related disorder showing multiple lumps. (ICD-10 L28.0; L28.1)

====Autoeczematization==== Autoeczematization (id reaction, autosensitization) is an eczematous reaction to an infection with parasites, fungi, bacteria, or viruses. It is completely curable with the clearance of the original infection that caused it. The appearance varies depending on the cause. It always occurs some distance away from the original infection. (ICD-10 L30.2)

====Viral==== There are eczemas overlaid by viral infections (eczema herpeticum or vaccinatum), and eczemas resulting from underlying disease (e.g., lymphoma). Eczemas originating from ingestion of medications, foods, and chemicals, have not yet been clearly systematized. Other rare eczematous disorders exist in addition to those listed here.

==Prevention== There is no good evidence that a mother's diet during pregnancy, the formula used, or breastfeeding changes the risk.

People with eczema should not get the smallpox vaccination due to risk of developing eczema vaccinatum, a potentially severe and sometimes fatal complication.

==Management== There is no known cure for some types of dermatitis, with treatment aiming to control symptoms by reducing inflammation and relieving itching. Contact dermatitis is treated by avoiding what is causing it.

===Lifestyle=== Bathing once or more a day is recommended, usually for five to ten minutes in warm water. Soaps should be avoided as they tend to strip the skin of natural oils and lead to excessive dryness.

There has not been adequate evaluation of changing the diet to reduce eczema. There is some evidence that infants with an established egg allergy may have a reduction in symptoms if eggs are eliminated from their diets.

===Moisturizers=== Moisturizing agents (also known as emollients) are recommended at least once or twice a day. Products that contain dyes, perfumes, or peanuts should not be used.

====Corticosteroids==== If symptoms are well controlled with moisturizers, steroids may only be required when flares occur. Once daily use is generally enough. Red burning skin, where the skin turns red upon stopping steroid use, has been reported among adults who use topical steroids at least daily for more than a year.

====Immunosuppressants====

Topical immunosuppressants like pimecrolimus and tacrolimus may be better in the short term and appear equal to steroids after a year of use. Their use is reasonable in those who do not respond to or are not tolerant of steroids. Treatments are typically recommended for short or fixed periods of time rather than indefinitely. Tacrolimus 0.1% has generally proved more effective than pimecrolimus, and equal in effect to mid-potency topical steroids. There is no link to increased risk of cancer from topical use of 1% pimecrolimus cream. A number of different types of light may be used including UVA and UVB; in some forms of treatment, light sensitive chemicals such as psoralen are also used. Overexposure to ultraviolet light carries its own risks, particularly that of skin cancer.

===Alternative medicine=== Limited evidence suggests that acupuncture may reduce itching in those affected by atopic dermatitis. There is currently no scientific evidence for the claim that sulfur treatment relieves eczema. It is unclear whether Chinese herbs help or harm. Dietary supplements are commonly used by people with eczema. Neither evening primrose oil nor borage seed oil taken orally have been shown to be effective. Both are associated with gastrointestinal upset. There is insufficient evidence to support the use of zinc, selenium, vitamin D, vitamin E, pyridoxine (vitamin B6), sea buckthorn oil, hempseed oil, sunflower oil, or fish oil as dietary supplements. There is little evidence supporting the use of psychological treatments. While dilute bleach baths have been used for infected dermatitis there is little evidence for this practice.

==Prognosis== Most cases are well managed with topical treatments and ultraviolet light. Dermatitis is most commonly seen in infancy, with female predominance of eczema presentations occurring during the reproductive period of 15–49 years. In the UK about 20% of children have the condition, while in the United States about 10% are affected. In the developed world there has been rise in the rate of eczema over time. The incidence and lifetime prevalence of eczema in England has been seen to increase in recent times.

Dermatitis affected about 10% of U.S. workers in 2010, representing over 15 million workers with dermatitis. Prevalence rates were higher among females than among males, and among those with some college education or a college degree compared to those with a high school diploma or less. Workers employed in healthcare and social assistance industries and life, physical, and social science occupations had the highest rates of reported dermatitis. About 6% of dermatitis cases among U.S. workers were attributed to work by a healthcare professional, indicating that the prevalence rate of work-related dermatitis among workers was at least 0.6%.

==History==

The term "atopic dermatitis" was coined in 1933 by Wise and Sulzberger. Sulfur as a topical treatment for eczema was fashionable in the Victorian and Edwardian eras.

==Society and culture==

The terms "hypoallergenic" and "doctor tested" are not regulated, and no research has been done showing that products labeled "hypoallergenic" are less problematic than any others.

==Research== A number of monoclonal antibodies are being studied as treatments including dupilumab.

== References ==

==External links==

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Category:Autoimmune diseases Category:RTT Category:Steroid-responsive inflammatory conditions Category:RTTEM

Texte soumis à la licence CC-BY-SA. Source : Article https://en.wikipedia.org/wiki/Dermatitis de Wikipédia

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