[Anogenital dermatoses--allergic and irritative causative factors. Analysis of IVDK data and review of the literature].

BACKGROUND: Anogenital dermatoses (AGD) are common and often very distressing. Clinically it is often unclear if allergic contact dermatitis or irritant dermatitis is involved. In order to optimize therapy and prophylaxis, it is essential to identify relevant allergens or irritants.

PATIENTS AND METHODS: Data of the Information Network of Departments of Dermatology (IVDK, data center in Göttingen) collected between 1999 and 2003 were analyzed. The anogenital area was involved in 1 168 patients with suspected allergic contact dermatitis. Clinical variables and patch test results were statistically compared with the remaining IVDK patch test population, the latter standardized for age and sex.

RESULTS: Allergic contact dermatitis had been suspected prior to patch testing in 39.5 %, while in 24.6 % this diagnosis was eventually confirmed. Irritant contact dermatitis was diagnosed in 11.8 %. Other diagnoses, included balanitis, lichen sclerosus et atrophicus and herpes genitalis. Positive reactions to cinchocaine (6.6 %), bufexamac (3.5 %) and benzocaine (2.4 %) were observed significantly more often among patients with anogenital dermatitis. Among those in whom co-factors were considered important (n = 422), wetness (38.4 %), occlusion (30.3 %), mechanical strain (4.7 %) and heat (3.6 %) were mentioned as irritation factors.

CONCLUSION: Because of the significantly higher frequency of sensitization to cinchocaine, benzocaine and bufexamac in patients with anogenital dermatitis, these ingredients should be used only with caution. According to the literature, ingredients of toiletries, cosmetics and contraceptives of any kind seem to cause allergic contact dermatitis rarely although there are several case reports. Comprehensive patch test including the standard series plus major sensitizers such as cinchocaine, benzocaine and bufexamac, and in particular patients' own skin care products, is recommended.