Allergic Contact Dermatitis
Just like eczema or atopic dermatitis; allergic contact dermatitis causes red, itchy, and sometimes oozing skin. Also, it can just as easily become infected. Looking at the skin it is sometimes hard to differentiate between all these red rashes. The history of the rash is extremely important to help differentiate if this is eczema or allergic contact dermatitis. Those with eczema or atopic dermatitis tend to have a life-long history of have red itchy rashes that come and go. On the other hand, those with allergic contact dermatitis tend to have a new onset rash. Maybe you used a new eyeliner and now your eyelids are red and itchy. The interesting thing with allergic contact dermatitis is that you could develop an allergy to a product you have been using your entire life. This sometimes makes it harder to figure out what is causing the rash.
A detailed history can sometimes pinpoint the cause of the allergy, but sometimes further investigation is needed. Allergy patch testing of the skin can help identify the offending allergen. Allergy patch tests are applied to the skin and left on for 2-3 days. Any area of the test that you develop a red spot is a potential allergen. Once the allergen is identified you will need to avoid all products containing that chemical. Usually once allergen avoidance is initiated the rash calms down and goes back to normal skin. However, sometimes the immune system is in “overdrive mode” and it could take months to calm down even after avoiding the allergen. Some people are allergic to numerous allergens at one time and others just one or two.
Treatments are similar to eczema and atopic dermatitis. Topical steroids creams, non-steroid creams, oral steroids, and in rare cases nonsteroidal immunosuppressive medications such as methotrexate or mycophenolate could be utilized.