Contact dermatitis

What is Contact dermatitis?

Contact dermatitis is a skin inflammation caused by direct contact with a number of substances. The process may be caused by direct chemical or physical irritation of the skin (irritant contact dermatitis), or it may be immune-mediated (allergic contact dermatitis). Irritants are the cause of 80% of contact dermatitis cases. Irritant contact dermatitis is seen more frequently in individuals whose work brings them into frequent contact with irritants such as soaps, detergents, chemicals and abrasives. These substances can either erode the protective oily barriers of the skin or physically injure its surface. Allergic contact dermatitis is seen in individuals who have been exposed to poison oak, poison ivy or poison sumac. Exposure to certain metals (nickel), rubber and elasticized garments, dyes, cosmetics and leather can sometimes result in allergic contact dermatitis.

How is it diagnosed?

History: The individual may report a previous reaction to a particular suspected substance. Symptoms usually include red, swollen areas on the skin that itch. Blisters may also be present. An occupational history is important in individuals with contact dermatitis. Certain manufacturing and outdoor occupations are at higher risk for exposure to allergens and irritants that may cause the dermatitis.

Physical exam: The early stages of dermatitis are characterized by areas of reddened (erythema) and swollen (edema) skin, accompanied by severe itching (pruritus). These symptoms are followed by development of large and small fluid-filled blisters (bullae and vesicles). The blisters may ooze and then crust over with scab formation.

The pattern of the dermatitis may aid in diagnosis. For example, poison ivy or oak allergic dermatitis is commonly seen as blisters streaked along a line on the arms or legs. In irritant dermatitis, the location will often suggest the cause. Scalp involvement suggests hair tints, sprays, or tonics; face involvement suggests cosmetics, soaps, or shaving materials.

Tests: Patch testing performed by a dermatologist may be utilized if allergic contact dermatitis is suspected. The patch test is only useful after the dermatitis has cleared.

How is Contact dermatitis treated?

Treatment consists primarily of identifying the offending agent and avoiding it. Hydrocortisone-containing creams are sometimes used. If severe dermatitis has developed after contact with poison ivy, poison oak, or poison sumac, a course of systemic corticosteroids may be required.

Medications

Topical creams, ointments or lotions may be recommended. These may include steroid preparations to reduce inflammation or lubricants to preserve moisture.

What might complicate it?

Bacterial infection of the affected area is a common complication.

Predicted outcome

If reexposure to the causative agent is prevented, the dermatitis will clear up.

Alternatives

Impetigo, scabies, dermatophytid, atopic dermatitis, and pompholyx have similar symptoms.

Appropriate specialists

Immunologist, dermatologist, and allergologist.

Last updated 3 April 2018