Contact dermatitis refers to a type of inflammatory skin rash (dermatitis) arising from direct skin exposure to a chemical substance. Contact dermatitis is comprised of allergic contact dermatitis and irritant contact dermatitis. Irritant contact dermatitis results from exposure to substances that cause irritation of the skin such as water, soaps, bleach and other irritants. Allergic contact dermatitis, on the other hand, occurs when a particular substance causes an allergic reaction in the skin resulting in an itchy rash. The most common cause of allergic contact dermatitis is poison ivy; other causes include cosmetics (particularly fragrances), metals, fragrances and topical antibiotics. Identifying the agent causing the contact dermatitis is important because removing the allergen is an essential part of the treatment that will lead to resolution of the rash. Patch testing is the diagnostic standard to identify these allergens.
C. Based on published results of patch testing, nickel is the most common positive metal allergen.
True. Nickel can be found in costume jewelry, tools, coins, metal buttons, metal equipment, cooking utensils and appliances.
B. Patch testing is a technique used to diagnose allergic contact dermatitis. It attempts to reproduce small scale allergic reactions of the skin from things that come in contact with it. Small amounts of test substances are applied to the skin under a patch of paper tape.
False. Irritant contact dermatitis is the most common form of contact dermatitis and is caused when substances such as solvents or other chemicals irritate the skin. The exposure typically produces red, often painful patches on the involved skin areas.
True. Many substances can irritate our skin. Soaps, cleansers, urine and water are mild irritants. Strong irritants like battery acid or fiberglass can also can cause irritant contact dermatitis.
True. Patch testing can help identify an allergic contact trigger for the dermatitis. In cases of irritant contact dermatitis, avoidance of the irritant triggers can help. Your allergist may also recommend prescription creams and lotions to treat the dermatitis.
True. P paraphenylene diamine or PPD (an allergen in hair dye) can cause dermatitis on the hands of beauticians. It can also cause symptoms in people who get their hair dyed including a blistering type rash over the face and scalp.
False. The fluid in the blisters of a poison ivy reaction is part of the allergic contact dermatitis reaction on the skin and contrary to public belief is NOT contagious. The oil from the poison ivy plant is the allergen that will result in an allergic reaction 24 to 96 hours after skin contact. Once your skin is washed with soap and water and all the plant oils are removed you are no longer contagious.