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Contact dermatitis

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Illustrations

Poison oak rash on the arm
Poison oak rash on the arm
Latex allergy
Latex allergy
Poison plants
Poison plants
Dermatitis, nickel on the sole
Dermatitis, nickel on the sole
Dermatitis, contact
Dermatitis, contact
Dermatitis, close-up of allergic contact
Dermatitis, close-up of allergic contact
Dermatitis, contact on the cheek
Dermatitis, contact on the cheek
Dermatitis, pustular contact
Dermatitis, pustular contact
Poison ivy on the knee
Poison ivy on the knee
Poison ivy on the leg
Poison ivy on the leg
Phytophotodermatitis on the hand
Phytophotodermatitis on the hand

Alternative names    Return to top

Dermatitis - contact; Allergic dermatitis; Dermatitis - allergic; Poison ivy; Poison oak; Poison sumac

Definition    Return to top

Contact dermatitis is an inflammation of the skin caused by direct contact with an irritating substance.

Causes, incidence, and risk factors    Return to top

Contact dermatitis is an inflammation of the skin caused by direct contact with an irritating or allergy-causing substance (irritant or allergen) vary in the same individual over time. A history of any type of allergies increases the risk for this condition.

Irritant dermatitis, the most common type of contact dermatitis, involves inflammation resulting from contact with acids, alkaline materials such as soaps and detergents, solvents, or other chemicals. The reaction usually resembles a burn.

The second most common type of contact dermatitis is caused by exposure to a material to which the person has become hypersensitive or allergic. The skin inflammation varies from mild irritation and redness to open sores, depending on the type of irritant, the body part affected, and the sensitivity of the individual.

Overtreatment dermatitis is a form of contact dermatitis that occurs when treatment for another skin disorder causes irritation.

Common allergens associated with contact dermatitis include:

Contact dermatitis may involve a reaction to a substance that the person is exposed to or uses repeatedly. Although there may be no initial reaction, repeated use (for example, nail polish remover, preservatives in contact lens solutions, or repeated contact with metals in earring posts and the metal backs of watches) can cause eventual sensitization and reaction to the product.

Some products cause a reaction only when they contact the skin and are exposed to sunlight (photosensitivity). These include shaving lotions, sunscreens, sulfa ointments, some perfumes, coal tar products, and oil from the skin of a lime. A few airborne allergens, such as ragweed or insecticide spray, can cause contact dermatitis.

Symptoms    Return to top

Signs and tests    Return to top

The diagnosis is primarily based on the skin appearance and a history of exposure to an irritant or an allergen.

According to the American Academy of Allergy, Asthma, and Immunology, "Patch testing is the gold standard for contact allergen identification." Allergy testing with skin patches may isolate the suspected allergen that is causing the reaction.

Patch testing is used for patients who have chronic, recurring contact dermatitis. It requires three office visits and must be done by a clinician with detailed experience in the procedures and interpretation of results. Patients should bring suspected materials with them, especially if they have already tested those materials on a small area of their skin and noticed a reaction.

Other tests may be used to rule out other possible causes, including skin lesion biopsy or culture of the skin lesion (see skin or mucosal biopsy culture).

Treatment    Return to top

Initial treatment includes thorough washing with lots of water to remove any trace of the irritant that may remain on the skin. Further exposure to known irritants or allergens should be avoided.

In some cases, the best treatment is to do nothing to the area.

Topical corticosteroid medications may reduce inflammation. Carefully adhere to instructions when using topical steroids because overuse of these medications, even low-strength over-the-counter topical steroids, may cause a troublesome skin condition. In severe cases, systemic corticosteroids may be needed to reduce inflammation. These are usually tapered gradually over about 12 days to prevent recurrence of the rash.

Wet dressings and soothing, antipruritic (anti-itch), or drying lotions may be recommended to reduce other symptoms.

Expectations (prognosis)    Return to top

Contact dermatitis usually clears up without complications within 2 or 3 weeks but may recur if the causal agent cannot be identified or avoided. Change of occupation or occupational habits may be necessary if the disorder is caused by occupational exposure.

Complications    Return to top

Secondary bacterial skin infections my occur.

Calling your health care provider    Return to top

Call your health care provider if symptoms indicate contact dermatitis and it is severe or there is no improvement after treatment.

Prevention    Return to top

Avoid contact with known allergens. Use protective gloves or other barriers if contact with substances is likely or unavoidable. Wash skin surfaces thoroughly after contact with substances. Avoid overtreating skin disorders.

Update Date: 4/20/2004

Updated by: Jonathan Kantor, M.D., Department of Dermatology, University of Pennsylvania Medical Center, Philadelphia, PA. Review provided by VeriMed Healthcare Network.

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