Contact dermatitis

Source: Wikipedia, the free encyclopedia.
Contact dermatitis
Contact dermatitis rash.
SpecialtyDermatology

Contact dermatitis is a type of acute or chronic inflammation of the skin caused by exposure to chemical or physical agents.[1] Symptoms of contact dermatitis can include itchy or dry skin, a red rash, bumps, blisters, or swelling. These rashes are not contagious or life-threatening, but can be very uncomfortable.

Contact dermatitis results from either exposure to allergens (allergic contact dermatitis), or irritants (irritant contact dermatitis). Allergic contact dermatitis involves a delayed type of hypersensitivity and previous exposure to an allergen to produce a reaction.[2] Irritant contact dermatitis is the most common type and represents 80% of all cases.[1] It is caused by prolonged exposure to irritants, leading to direct injury of the epidermal cells of the skin, which activates an immune response, resulting in an inflammatory cutaneous reaction.[1] Phototoxic dermatitis occurs when the allergen or irritant is activated by sunlight. Diagnosis of allergic contact dermatitis can often be supported by patch testing.[3]

Epidemiology

Contact dermatitis constitutes 95% of all occupational skin disorders.[4] There are few accurate statistics on the incidence and prevalence of contact dermatitis.[5] The results of the few studies that have been undertaken cannot be compared because of methodological differences.[5]

Signs and symptoms

Contact

epidermis (the outermost layer of skin) and the outer dermis (the layer beneath the epidermis).[6]

Contact dermatitis results in large, burning, and itchy rashes. These can take anywhere from several days to weeks to heal. This differentiates it from

contact urticaria (hives), in which a rash appears within minutes of exposure and then fades away within minutes to hours. Even after days, contact dermatitis fades only if the skin no longer comes in contact with the allergen or irritant.[7]
Chronic contact dermatitis can develop when the removal of the offending agent no longer provides expected relief.

Irritant dermatitis is usually confined to the area where the irritating substance actually touched the skin, whereas allergic dermatitis may be more widespread on the skin. Irritant dermatitis is usually found on hands whereas exposed areas of skin. Symptoms of both forms include the following:

While either form of contact dermatitis can affect any part of the body, irritant contact dermatitis often affects the hands, which have been exposed by resting in or dipping into a container (sink, pail, tub, swimming pools with high chlorine) containing the irritant.

Causes

The percentage of cases attributable to occupational contact dermatitis varies substantially depending on the industries that predominate, the employment that people have, the risks to which they are exposed, the centers that record cases, and variances in defining and confirming diagnoses.[9]

Common causes of allergic contact dermatitis include:

alkyl resorcinols in Grevillea banksii and Grevillea 'Robyn Gordon' are responsible for contact dermatitis.[11] Bilobol, another alkyl resorcinol found in Ginkgo biloba fruits, is also a strong skin irritant.[12]

Common causes of irritant contact dermatitis include solvents, metalworking fluids, latex, kerosene, ethylene oxide, paper, especially papers coated with chemicals and printing inks, certain foods and drink,[13] food flavorings and spices,[14] perfume,[13] surfactants in topical medications and cosmetics, alkalis, low humidity from air conditioning, and many plants. Other common causes of irritant contact dermatitis are harsh alkaline soaps, detergents, and cleaning products.[15]

There are three types of contact dermatitis:

photocontact dermatitis
. Photocontact dermatitis is divided into two categories: phototoxic and photoallergic.

Irritant contact dermatitis