Allergic Contact Dermatitis is one of the most severe forms of dermatitis. Not only is it accompanied by an intense–sometimes painful–rash, but it also involves figuring exactly what caused the reaction and then avoiding that ingredient like the plague.
Dr. Tsippora Shainhouse, a dermatologist at Rapaport Dermatology of Beverly Hills, explains the telltale symptoms of Allergic Contact Dermatitis and what to do if you think you have it.
What Is Allergic Contact Dermatitis?
Allergic Contact Dermatitis refers to a true, type four delayed-hypersensitivity reaction to a topical agent. A skin rash will not develop until after at least two exposures, because the skin needs a chance to become sensitized. Once the immune system recognizes this allergen, it will react every time the skin is exposed. This is different than just irritant contact dermatitis.
In acute cases, the skin can be red and blistered; for festering, milder cases, the rash can be pink, bumpy or scaly; in cases of chronic exposure and inflammation, there are usually thick, pink/purple, scaly plaques. Because it is caused by direct contact with an allergen, there is usually a discrete patch of involvement where the allergen touched. Use this information to help determine what might have come in contact with the skin. For example, if the irritation develops on your earlobes, you may be reacting to the metals in your earrings like nickel, silver and/or gold. Also, unlike irritant contact dermatitis, this rash can, technically, “spread” if fingers touch a transferable allergen and then touch another body part.
How To Treat Allergic Contact Dermatitis?
Allergy patch testing can be performed, once the rash clears, to help verify a suspected contact allergen. Treatment includes avoiding the offending sensitizing agent (it can take weeks to get out of the system), topical steroid creams to reduce the inflammation and oral antihistamines to prevent the histamine-release associated with allergic reactions. Some people can require oral steroids. Gentle, fragrance-free soaps and plain moisturizing creams (Vaseline, coconut oil) are best until the allergen is determined. After it is verified, read labels and be sure to avoid that ingredient.