Allergic contact dermatitis is a common cause of dermatitis
and a frequent diagnostic consideration in dermatology.
Patch testing to a broad array of relevant allergens is the only
way to identify the substances causing allergic contact dermatitis.
Although the results of patch testing can often be rewarding
for the patient and physician, the process of patch testing can be
expensive, challenging, time consuming, and frustrating. Often,
it raises more questionsthan answers. Findingthe one substance
that definitively accounts for the patient’s dermatitis is relatively
rare. More often, a number of patch-test reactions are noted that
might or might not be contributing factors in the patient’s dermatitis.
Patch testing is a somewhat imprecise science requiring substantial
clinical judgment.What allergens should be considered?
How should patch-test reactions be read and interpreted? What
should patients be taught about allergen avoidance? This article
attempts to clarify some of the questions surrounding patch
testing and provide practical guidance for the novice patch tester.
Specifically, this article will describe when to perform patch
testing, describe the process of patch testing, recommend useful
allergen series, and summarize notable allergens.