Recent evidence suggests that 0.1% tacrolimus ointment is an effective treatment of atopic dermatitis. Tacrolimus is an immunosuppressive agent that interferes with cell-mediated immunity. We have observed 2 cases of eczema herpeticum among 36 patients with atopic dermatitis treated with a topical preparation containing 0.1% tacrolimus. A 29-year-old male patient developed generalized herpetic lesions on his face on the 4th day of treatment. His SCORAD was then 73, and the tacrolimus blood level was 7.5 ng/ml. A 23-year-old woman developed disseminated herpetic lesions on her neck, face, shoulders and legs during the 9th week of treatment. Her SCORAD was then 41, tacrolimus blood levels were <3 ng/ml 2 weeks before the infection. Herpes simplex virus type 1 antigens were identified in several lesions by direct immunofluorescence in both patients. Neither patient recalled previous episodes of cold sores. The lesions resolved quickly under intravenous acyclovir treatment but resulted in important facial scarring in the male patient. Conclusions: Eczema herpeticum is a well-known complication of atopic dermatitis. Available data do not allow to link topical tacrolimus with an increased risk for eczema herpeticum, but they are insufficient to exclude an association. Future studies and careful documentation of cases are needed in order to better characterize patients at risk.

In that respect, it is interesting to note in the letter from Uter et al. (2001) that the percentage of colophony sensitive patients reacting to oakmoss is increasing with regard to the severity of their allergy. Thus the percentage of patients reacting to oakmoss is 14.7% in patients reacting to colophony with erythema only (``?''), 19.4% in those with a``+'' reaction, 30% in those with a``++'' reaction, and 53.3% in those with very strong (``+++'') reactions. This later ®gure is very similar to the one we observed (53%) on our selected patients. We suggest that more care should be taken when stating that 12823 patients were patch tested between 1992 and 1999 to the same oakmoss material as the one we have been using in our study. Over a period of time patch test suppliers will use different batches of oakmoss material either from the same supplier or from different suppliers. The oak moss sample we have been using is identical to the material used by Trolab (Reinbek, Germany) from 1999 to now. Therefore a comparison of data can only be valid if conducted in the period 1999±2000. We are of course well aware that oakmoss and treemoss are skin sensitizers, not only because of the presence of resin acids but also because of the presence of other sensitizers, some of which are known in the literature (Dahlquist et al., 1980). Among our 17 patients two reacted to the oakmoss from Chemotechnique (Malmo È, Sweden), despite a low content of resin acid, which probably indicates a true co-sensitization to oakmoss and colophony.

In that respect, it is interesting to note in the letter from Uter et al. (2001) that the percentage of colophony sensitive patients reacting to oakmoss is increasing with regard to the severity of their allergy. Thus the percentage of patients reacting to oakmoss is 14.7% in patients reacting to colophony with erythema only (``?''), 19.4% in those with a``+'' reaction, 30% in those with a``++'' reaction, and 53.3% in those with very strong (``+++'') reactions. This later ®gure is very similar to the one we observed (53%) on our selected patients.We suggest that more care should be taken when stating that 12823 patients were patch tested between 1992 and 1999 to the same oakmoss material as the one we have been using in our study. Over a period of time patch test suppliers will use different batches of oakmoss material either from the same supplier or from different suppliers. The oak moss sample we have been using is identical to the material used by Trolab (Reinbek, Germany) from 1999 to now. Therefore a comparison of data can only be valid if conducted in the period 1999±2000.We are of course well aware that oakmoss and treemoss are skin sensitizers, not only because of the presence of resin acids but also because of the presence of other sensitizers, some of which are known in the literature (Dahlquist et al., 1980). Among our 17 patients two reacted to the oakmoss from Chemotechnique (Malmo È, Sweden), despite a low content of resin acid, which probably indicates a true co-sensitization to oakmoss and colophony.

No abstract