Contact dermatitis (sometimes called allergic contact dermatitis) is caused by allergens that come into contact with the skin. Allergic contact dermatitis often clears up on its own when sufferers avoid the offending agent.
Contact dermatitis is an example of hypersensitivity. Literally defined as “inflamed skin,” dermatitis appears in a localized area as a rash, small blisters, swelling, or redness. Contact dermatitis has two categories of distinction: irritant contact dermatitis and allergic contact dermatitis. Irritant contact dermatitis is caused by a substance that is likely to cause a reaction in nearly anyone who is exposed to it in large quantities.
Allergic contact dermatitis is caused by your body coming into contact with an allergen and reacting. It’s the body’s immune system being hypersensitive to a foreign agent. “The body may come into contact with the allergen through direct contact, such as touching, or through airborne contact, such as an allergen landing on the skin,” says Dr. Schalock. When the allergen comes into contact with the skin, redness, swelling, a rash, or blisters develop, creating an itchy, irritated area on the skin. If the exposure is brief and then removed, the reaction will clear on its own.
Nearly anything can be the cause of allergic contact dermatitis, because each person’s body responds differently to allergens. So, jewelry, plants, lotions, glues, polish, acrylics, wool, gasoline, perfume, metals — the list goes on and on — could cause the skin to react and swell in one person, but be completely benign to another. Another complexity of allergic contact dermatitis is that a person could have been in contact with a substance — a lotion, detergent, salon products — for years with no reaction and then suddenly develop a reaction without explanation.