What Is the Skin Condition Dermatitis?

Symptoms, Diagnosis, and Treatment

Dry skin on the hands.
Dry skin on the hands. Linda Steward/Getty Images

The simple definition of dermatitis is inflammation of the skin. Almost any rash can be thought of as dermatitis, based on this definition, including psoriasis, skin cancer, and seborrhea. However, not every rash is called dermatitis.

Appearance and Symptoms

A dermatitis rash is itchy and red, and it may or may not have distinct margins. The specific look of the rash depends on the amount of time that it has been present.

Acute dermatitis has blisters, subacute dermatitis has scaling and crusting, and chronic dermatitis has lichenification.

Types of Dermatitis

There are several distinct types of dermatitis that are delineated by the cause or the cellular mechanism that's responsible for the rash. One specific type is allergic contact dermatitis. This is a delayed hypersensitivity reaction involving allergens and antibodies. Another form of dermatitis is irritant contact dermatitis. This is exposure to irritating chemicals or detergents. There's also atopic dermatitis, an allergic-type reaction that is accompanied by hay fever, asthma, and very dry skin. Other types of dermatitis include:

  • Stasis dermatitis: Occurs on the ankles and lower legs of people with venous insufficiency
  • Diaper dermatitis: A type of irritant dermatitis that's caused by extended exposure of the skin to wet diapers
  • Dyshidrotic dermatitis (pompholyx): A type of dermatitis on the hands or feet that is characterized by redness, scaling, and deep blisters
  • Nummular dermatitis: Coin-shaped patches that occur anywhere on the body in relation to dry skin
  • Seborrheic dermatitis (cradle cap): Yellow, greasy scales like dandruff on the scalp and hair-bearing areas of the head, neck, and upper chest
  • Autosensitization dermatitis (Id reaction): An itchy rash that occurs in response to an intense inflammatory process somewhere else on the body, especially a fungal infection
  • Lichen simplex chronicus: A rash that's caused by long-term scratching of an area, producing thickened skin

Diagnosis

Generally, dermatitis is diagnosed clinically, meaning based on the history and appearance of the rash. If possible, the exact type of dermatitis is delineated, but sometimes it is difficult to tell the difference between the dermatitis types. There are very few tests performed that help clarify the type of dermatitis. Some examples of tests that may help with the diagnosis are skin tests for contact or atopic dermatitis or a KOH test identifying a fungal infection.

Treatment

Dermatitis is best treated if the type is known. However, there are measures that can be taken to improve symptoms even if the exact dermatitis type is not known.

For one, keep skin as moisturized as possible, since dry skin causes cracks in the outer layer of skin (the epidermis), inhibiting the barrier function of the skin. Reduce itching and scratching with topical medications or antihistamines. Avoid irritating and drying substances such as perfumes or harsh detergents, and treat other rashes, especially fungal infections, even though they may not seem related.

Topical Steroids and Dermatitis

Topical steroids are often used to treat dermatitis.

Topical steroids come in different strengths and can have significant side effects. All topical steroids, except hydrocortisone cream, must be prescribed by a health care provider.

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