A lot of my patients come to our office with a new rash, and the main question asked is: “What caused this skin rash?” Many times it can be very difficult to pinpoint exactly what causes a skin rash without formal testing. One of the most common causes of skin rashes are due to contact with certain chemicals used in our day to day lives such as:
- Laundry detergents
- Clothing dyes
Allergic Contact Dermatitis is the name we use for reactions to chemicals found in these products. The most common misconception is that products we have used in the past cannot cause our skin to react. This concept is wrong, due to the fact that our skin can become sensitized to chemicals.
Sensitized means our body does not have an allergic reaction when it first comes into contact with the chemical, but the following time(s) our skin is exposed. An example would be the antibiotic ointment Neosporin, many people used this product throughout childhood without a problem, and over time our body has the ability to become sensitized and allergic to it. Neosporin is an extremely common contact allergy due to this.
How can I find out which chemicals I’m allergic to?
Answer: Patch Testing.
Patch Testing is a series of testing where 80 different chemicals are applied to the back. At our office, the patches are left in place for two days, removed and read on day three and on day five. Chemicals range from fragrances, dyes, metals, plant chemicals, and even gold!
When patches are removed, we can determine whether or not the skin has mounted an immune response to the allergens, and let you know what to look for in products for possible triggers. The most important thing a patient can do after being told what they react to on a patch test is the detective work at home to see what products they use which actually contain the allergen.
Patients with an allergic contact dermatitis are recommended to avoid potential allergens, and commonly given a prescription for topical steroid use during flares of rashes on the skin. Over the counter 1% hydrocortisone may be used in milder reactions as well.