Most people associate allergies with food, but sometimes allergens do not have to be ingested to cause a flare up or allergic reaction; sometimes all you have to do is come into contact with them. Skin allergies like these are called contact dermatitis and can be found among males and females of all ages.
There are three types of dermatitis, irritant dermatitis (ID), allergic contact dermatitis, and over-treatment dermatitis. Irritant Dermatitis is the most common form and appears when skin comes into direct contact with an irritant such as acids, soaps, detergents,or other harsh chemicals. The irritated area will typically resemble a burn. Allergic contact dermatitis appears when you come into contact with something you know you are allergic to, and most symptoms will appear 24-48 hours after initial contact. The final form, over-treatment dermatitis, occurs when a topical cream used for one skin disorder causes another one, making the problem worse.
The most common skin irritants are plants like poison oak or poison ivy, alkaline materials, latex, and perfume. Some products may not cause a reaction right away, but continued use of heavy products on your skin may lead to dermatitis. The only way to test for contact dermatitis is with a patch test, where a doctor sticks different allergens on your body and leaves them there for two days to see the result. As obvious as it may sound, it works for people who may use multiple products everyday and are working to figure out what their body is reacting to. Contact dermatitis usually lasts for 2-3 weeks, but if symptoms persist talk to you doctor about treatment. Lastly, be sure to use any prescribed topical treatments correctly to prevent further harm to your skin!
References:
http://www.nlm.nih.gov/medlineplus/ency/article/000869.htm
