Contact allergy to methyldibromo glutaronitrile--data from a 'front line' network.

The preservative methyldibromo glutaronitrile (MDBGN) has caused an epidemic of contact allergy in Europe. However, most data concerning contact allergy comes from hospital departments of dermatology. As a part of the primary health care sector, Danish dermatologists in private practice provide the front line of care for patients with skin diseases. Data from this source may therefore better reflect trends in the general population than material from hospital departments of dermatology. In this study, the frequency of MDBGN allergy and the characteristics of patients seen by dermatologists in private practice were studied. In 1 year, 2146 patients were patch tested by the participating dermatologists from 4 clinics in various parts of Denmark. 5% (110) had positive patch tests to MDBGN, with no difference between the sexes. After adjustment was made for other background variables, multivariate analysis using logistic regression showed a significant association between hand eczema and MDBGN allergy (OR 2.5, P < 0.001). In 53 cases (52.4%), the patch test reaction to MDBGN was judged to be of current relevance. Creams and lotions accounted for 31% of the identified causative products and liquid soaps for 23%. It is concluded that contact allergy to MDBGN is frequent among patients seen by dermatologists in private practice. This is consistent with results from hospital departments of dermatology in Europe and indicates a general trend and ongoing epidemic in the general population. The significant relationship between hand eczema and MDBGN allergy is of concern, and the finding that wash-off products, especially liquid soaps, play a significant role in MDBGN allergy calls for a revision of the safety assessment of MDBGN in wash-off products.