Dermatitis

What is Dermatitis?

Dermatitis is the generic label referring to inflammations of the skin. Sometimes due to an allergy, dermatitis, in many cases, occurs without any known cause. Apart from eczema, the main forms of dermatitis are contact dermatitis, seborrheic dermatitis, and photodermatitis.

Contact dermatitis occurs when the skin comes in direct contact with an irritating substance. The rash can either be a reaction to the toxic effect of the substance or it may be an allergic response. Common irritants are detergents, nickel (found in jewelry and the fastenings of underclothes), chemicals in rubber gloves and condoms, certain cosmetics, and topical (to use on the skin) medications. Poison oak and ivy (including inhaling smoke from the burning of these plants) most frequently cause allergic contact dermatitis. About twenty percent of contact dermatitis cases are due to allergic reactions. Acute reactions usually occur within 24 to 48 hours after contact.

Continued exposure results in a chronic dermatitis. On the scalp, dandruff is the most common illustration of seborrheic dermatitis. The exact cause is unknown, but the rash often develops during times of stress.

Photodermatitis is the reaction of skin to photochemical activity such as sunlight, x-rays or ultraviolet light. Certain oral medications can make the skin suddenly more sensitive to sunlight.

Although atopic dermatitis has no known cause, it happens to people who have sensitive skin. There may be an allergic, hereditary, or psychological tendency. In about 70% of all cases, there is a family history of the disease. Seldom occurring before two months of age, about three percent of all infants have atopic dermatitis. Atopic dermatitis may also occur for the first time quite late in life.

How is it diagnosed?

History: A rash, which can vary considerably according to the substance that caused it, develops at the site where the skin came in contact with the irritating substance. Symptoms usually include itching, burning, and stinging. The affected area appears red and irritated. Small blisters may develop, break open, and crust over. Contact dermatitis may occur after a change in detergent, soap, cosmetics, jewelry or topical medication. Complaints from poison oak or ivy are often reported after working outdoors or a hike in the woods. In adults, the main symptom of atopic dermatitis is itching and scratching. Secondary infections are common. Symptoms of seborrheic dermatitis include a red, scaly, itchy rash that usually starts on the scalp, and/or on the face (particularly nose and eyebrows), chest, and back. Photodermatitis is characterized by sunburn. The reddened, inflamed skin can also blister.

Physical exam: Rash or inflammation is examined in an attempt to identify cause.

Tests: A skin test may be done to identify source of allergic reaction. Suspected substances are applied to the skin on individual's back. They are kept in place for several days with identifying tapes to see whether any produce a patch of dermatitis.

How is Dermatitis treated?

Treatment depends on underlying cause of the inflammation and must be tailored to each case. If the agent causing contact dermatitis can be avoided, the skin inflammation will usually clear itself within a few weeks. Calamine lotions can dry lesions and help to control the itching.

Antihistamines help relieve itching, especially at night. Seborrheic dermatitis involving the scalp are treated with shampoos. For severe cases, anti-inflammatory (corticosteroid) lotion may be applied to affected area. An oral antibiotic may be needed for a brief period to control a secondary infection.

Medications

Brand	Generic	Label	Rating
Contact dermatitis
Atarax	Hydroxyzine
Aristocort	Triamcinolone
Atopic dermatitis
Sinequan	Doxepin
Prograf	Tacrolimus
Gengraf	Cyclosporine
Seborrheic dermatitis
Medrol	Methylprednisolone

What might complicate it?

Secondary infections, exfoliative erythroderma, weight loss, mental and emotional problems, and poor general health may complicate the dermatitis.

Predicted outcome

Predicted outcome depends on the underlying cause. If the agent causing contact dermatitis can be identified and avoided, the skin inflammation will usually clear itself within a few weeks. Dermatitis from unknown cause must be treated symptomatically as needed.

Alternatives

Urticaria (hives), erythema multiforme, lichen planus, pityriasis rosea and psoriasis are possibilities.

Appropriate specialists

Dermatologist.

Last updated 25 November 2011