Contact allergy to ingredients of topical medications: results of the European Surveillance System on Contact Allergies (ESSCA), 2009-2012.

Several of the substances warrant routine screening for contact allergy, i.e. patch testing in a baseline series. However, in view of a vast number of other topical agents, additional patch testing with the suspect topical drug preparations (including natural remedies and cosmetics) is warranted. In the event of a positive test to the (pharmaceutical) product, single ingredients should be tested individually to precisely identify the hapten(s). Copyright © 2016 John Wiley & Sons, Ltd.