OBJECTIVE: Allergic contact dermatitis is a common anogenital disease.

STUDY DESIGN: The results of patch testing performed on 1,008 patients evaluated for allergic anogenital contact dermatitis from 21 dermatologic departments in the Information Network of Departments of Dermatology (IVDK) from 1992 to 1997 were analyzed.

RESULTS: A final diagnosis of allergic contact dermatitis was made in 351 patients (34.8%). Irritant contact dermatitis was diagnosed in 230 patients (22.8%) and other, nonspecified forms of perianal eczema in 228 patients (22.6%). The remaining cases were due to other distinct dermatologic diseases. Analyzing patch test data from this large group of patients showed that the allergen spectrum resembled that of all patients (54,000) tested from 1992 to 1997. However, dibucaine HCl ranked fourth among contact allergens in the study population. Positive reactions to (chloro-)-methyl-isothiazolinone and to benzocaine were observed more frequently among patients with anogenital complaints as compared to the total IVDK population (3.7% vs. 2.5% and 2.7% vs. 1.5%, respectively). In general, active agents of topical medications and popular remedies, preservatives and ointment bases appeared to cause allergic reactions most frequently.

CONCLUSION: Patients with chronic anogenital diseases seem to have a high risk of becoming sensitized. For patch testing we recommend the standard series, dibucaine HCl, propolis, bufexamac and other ingredients from topical preparations according to the patient's history.