"Eczema" may develop for many reasons, ranging from a genetic predisposition ("atopic dermatitis") to dry skin ("asteatoticdermatitis"). Among the causes of eczema is "allergic contact dermatitis (ACD)." ACD occurs when a person develops a rash after a chemical touches their skin. Poison ivy is a typical example. However, there are many potential allergens and ways they can affect the skin.
If ACD is suspected, the appropriate next step is often "patch testing". This involves placing sticky, allergen-containing patches on the patient's back. If a dermatitis is found when the patches are removed, an allergy is documented. The patient is provided with information about that allergen as well as a list of products that do not contain the allergen.
Our practice uses a panel of allergens recommended by the American Contact Dermatitis Society as the most likely allergens in North America. Additionally, the utility of this testing may be increased if patients are tested with samples of their own cosmetics, sunscreens, perfumes, topical medications and other products.
Applying Patches Removing Patches Documenting Patches