Patch testing in patients with perianal eczema

Reports show that between 25% and 78% of patients with anogenital dermatitis have positive patch test results. Consequently, patch testing would appear to be warranted in patients presenting with eczema in the anogenital region. The objectives of the present study were to identify the most common allergens in patients with perianal eczema and to determine which allergen series are most useful for patch testing in patients with this condition.

We performed a retrospective review of patch test results in patients with only perianal eczema between 2001 and 2012.

Of the 37 patients with perianal eczema, 16 had a positive reaction; methylchloroisothiazolinone/methylisothiazolinone was the main allergen involved. With the exception of 1 case of sensitization to gentamicin, all the positive results with present relevance were to allergens from the standard series of the Spanish Contact Dermatitis and Skin Allergy Research Group (GEIDAC) or to the patient's own products.

In our experience, methylchloroisothiazolinone/methylisothiazolinone is the main allergen involved in perianal eczema, and sensitization often results from using wet wipes. Patch testing in perianal eczema should be based on the GEIDAC standard series and the patient's own products.