Background Allergic contact dermatitis is a leading cause of periorbital dermatitis. The extremely thin nature of the periorbital skin may facilitate allergen penetration, making this area particularly susceptible to allergic contact sensitisation. In this study, we assessed sensitisation rates to ingredients of common topical ophthalmic agents.

Materials and methods Data collected by 57 participating centres of the Information Network of Departments of Dermatology (IVDK) were analysed retrospectively. Of the 101 403 patients patch tested between January 2001 and December 2010, 4779 patients suffered from periorbital dermatitis and 1158 patients were specifically tested to the ophthalmic tray. Patch test results of the latter group were analysed in detail.

Results The ophthalmic tray consisted of seven preservatives, six antibiotics and three other ophthalmic agents. Antibiotics (gentamicin, neomycin, kanamycin) were the leading group of allergens. Patch testing with preservatives often elicited irritant or weak positive reactions.

Conclusions When suspecting contact allergy in the periorbital area, patch testing should be considered in order to identify and avoid offending allergens. Testing to substances from a standardised ophthalmic tray is recommended, but it is preferable to test the actual drops or creams since many chemicals that are present in ophthalmics are not available as commercial test allergens. Given their wide use, preservatives cannot be regarded as common allergens, while antibiotics cause more often true allergic reactions necessitating a long-term avoidance.