Does smoking influence the efficacy of bath-PUVA therapy in chronic palmoplantar eczema?

Bath-PUVA therapy has been described as successful treatment for palmoplantar eczema. However, our own observations showed that patients with palmoplantar eczema of the dyshidrotic or hyperkeratotic type responded only partially to bath-PUVA therapy. In order to evaluate environmental influences possibly having an impact on the efficacy of this therapy, smokers and non-smokers suffering from palmoplantar eczema treated with bath-PUVA therapy were compared. A retrospective study was conducted involving 62 patients, 39 non-smokers and 23 smokers, with palmar and/or plantar eczema resistant to local corticosteroids. Bath-PUVA therapy was performed according to the European standard regimen for oral PUVA therapy. The total number of treatments and the cumulative UVA-dose were similar in smokers and non-smokers (smokers 24+/-17.7 (mean+/-SD) and 67.6+/-51.3 J/cm2 vs. non-smokers 25.7+/-16.3 and 68.5+/-49.3 J/cm2). In the group of non-smokers, 31% showed complete remission (CR; 100% clearance), 33% partial remission (PR; more than 50% clearance) and 36% no change after treatment (NC; less than 50% clearance). In contrast, the group of smokers showed only 13% CR and 22% PR, whereas 65% exhibited NC. The differences regarding complete or partial remission between the groups were statistically significant (Student t-test for paired samples; P<0.05). Regarding the different type of eczema, bath-PUVA proved to be more successful in the dyshidrotic type of eczema as compared to the hyperkeratotic type in non-smokers (P<0.05). In the group of smokers no CR was achieved in patients suffering from the dyshidrotic form of eczema. Smoking is likely to be a reason for the failure of bath-PUVA therapy in the treatment of chronic palmoplantar eczema, in particular regarding smokers with eczema of the dyshidrotic type where no complete remission was achieved.