Contact dermatitis is a term for a skin reaction (dermatitis) resulting from exposure to allergens (allergic contact dermatitis) or irritants (irritant contact dermatitis). Phototoxic dermatitis occurs when the allergen or irritant is activated by sunlight.
Contact dermatitis is an inflammation of the skin that results from direct contact with certain substances such as soap, cosmetics, jewelry or weeds. The resulting red itchy rash is not contagious or life-threatening but it can be very uncomfortable.
Successful contact dermatitis treatment consists primarily of identifying what is causing the inflammation. If you can avoid the offending agent, the rash usually disappears in two to four weeks. Self-care measures (wet compresses and anti-itch creams) can help soothe your skin and reduce inflammation.
Signs and symptoms of contact dermatitis include red rash or bumps, itching (which may be severe), dry red patches (which may resemble a burn), blisters and draining fluid from the involved skin in severe cases, skin rash limited to the exposed area, and pain or tenderness.
In contact dermatitis, only the areas of skin exposed to the offending substances react. The area with the greatest exposure reacts most severely.
Based on the cause, contact dermatitis falls into two categories (irritant contact dermatitis and allergic contact dermatitis).
Irritant contact dermatitis is more common and results from repeated contact with a substance, such as soap, cosmetics or skin products, including deodorant (that irritates the skin). The exposure produces red, dry itchy patches usually on the hands, fingers and face. Some substances, such as bleach or strong acids can cause irritant contact dermatitis after just one exposure. These substances typically remove oil and the protective barriers from the skin.
Allergic contact dermatitis is caused by a reaction to substances called allergens. The resulting reaction is your body's response to the sensitive agent. Allergic contact dermatitis produces a red rash, bumps and sometimes blisters when severe.