We often see patients that are experiencing some type of discomfort with allergies on their skin. Sometimes their skin itches severely, has a visible rash or redness and occasionally can be scaly or swelling. Here at Dermatology Associates we test and treat both forms of contact dermatitis which are allergic contact dermatitis and contact irritant dermatitis.

What is Allergic Contact Dermatitis?
Contact allergic dermatitis is caused by an allergic reaction to something which has intentionally or unintentionally been applied to the skin. In most cases, prolonged exposure to the chemical causing the reaction is required for the allergy to develop. For instance, if you’re allergic to Neosporin, you may have been using it for several years previously without problems until the allergy suddenly appears. In some cases, the allergy appears much quicker. Poison ivy/oak dermatitis typically occurs about 10 days after exposure if there has been no previous allergic reaction. Once you have developed an allergy to a particular chemical, you will react with an allergic dermatitis every time you are exposed to it.

What is Contact Irritant Dermatitis?
Contact irritant dermatitis is much more common and can appear in anyone under the right circumstances. This is basically an irritation of the skin caused by any number of topicals which might be too irritating on any given day. As an example, you might have done a mild peel on your face and then applied a face cream which caused an irritation because of the previous peel but that same cream doesn’t cause problems ordinarily.

What Are the Signs and Symptoms?
The signs and symptoms of both forms of dermatitis are redness and scaling. With allergic dermatitis there is often some puffiness or swelling of the skin and itching. In the more severe cases such as with poison oak/ivy blisters often appear. The signs and symptoms of contact dermatitis appear in the areas of contact only. Sometimes this can be misleading however because allergy to nail polish most commonly shows up on the eyelids (by rubbing your nails on your eyelids).

What are treatment options for Contact Dermatitis?
The primary treatment for contact dermatitis is to eliminate the cause. With irritant dermatitis you can usually go back to using the same products once the underlying irritation has resolved. With allergic contact dermatitis it is imperative to find the chemical causing the reaction because the reaction will reoccur with every exposure. We do this with a procedure called patch testing which is performed by Dr. Marshall Welch. Through this procedure, a long list of chemicals that are known to cause problems and those chemicals are applied in small patches to the back for 48 hours. The patches are removed after 48 hours and the final results are assessed 2-4 days later. A positive result will show up as a small red spot under the patch. Although this is “allergy testing “we are not testing for foods, dust, plants, grass and mold etc. These are the scratch tests done by an allergist. Patch testing is covered by most insurance plans and you will know the results in a week. We will give you an information sheet on every chemical you react to for your records.

Peter Jenkin, MD, FAAD, FRCPC
Board-Certified Dermatologist
Dermatology Associates of Seattle

Peter Jenkin, Clinic Director and Board-Certified Dermatologist at Dermatology Associates of Seattle is available for consultation. For scheduling and information, visit us at appointments.dermatology.associates