What is Contact Dermatitis?
Contact dermatitis is a group of skin reactions that are the result of direct exposure to either irritants or allergens. These two causes of contact dermatitis can produce similar effects, including:
- Red, bumpy or burn-like rash on the skin
- Itchy, painful or burning skin
- Blisters and draining fluid
Irritant contact dermatitis is more common. It results from substances such as solvents or other chemicals coming in contact with exposed skin and causing direct irritation. This rash often presents as red, painful, itchy patches on the areas of exposed skin.
Allergic contact dermatitis occurs when an allergen triggers an immune response within the skin, and is often worse in areas of thinner skin (eyelids, earlobes, etc.) than thicker skin (palms of hands and soles of feet). Metals, perfumes, dyes, rubber (latex) products, topical medications and cosmetics are frequent causes.
A thorough history is the first step in evaluating possible contact dermatitis. Timing of exposure to suspected triggers is especially important. Review of the patient's history dictates whether testing is warranted. Testing is usually done by applying a patch containing common allergens to the back for 48 hours, after which the patch is removed and interpreted by a provider.