Effect of monochromatic excimer light on palmoplantar pustulosis: a clinical study performed in a private clinic by a dermatological specialist.

Palmoplantar pustulosis (PPP) is currently treated with various modalities, including excimer light, a form of ultraviolet lamp. This study reports effect of excimer light treatment in 34 Japanese PPP patients treated at a private clinic by one doctor, who was certified as a dermatological specialist by the Japanese Dermatological Association. The statistical analyses were performed upon a collaborative basis with faculties in universities. Disease response scores were determined by response to excimer light treatment. Scores of 1, 2, 3 or 4 were assigned to patients whose palmoplantar pustular psoriasis area and severity index (PPPASI) decreased to 25% or less, 25.1–50%, 50.1–75% or more than 75.1% of pretreatment PPPASI, respectively. In this study, 44.1% PPP cases had scores of 1 or 2, and considered good responders to excimer light treatment. There were no statistical differences between males and females, and between older (≥40 years) and younger groups (≤39 years) in terms of disease response score. Disease duration did not show any significant difference among these scores. Treatment times, total amount of ultraviolet and total treatment duration showed significant differences between score 1 and score 4 groups (P = 0.0164, =0.0137 and =0.0267, respectively). Particular interest was paid to smoking habits. Smoking in male patients was significantly higher than that in female patients (P = 0.0169). There was no statistical difference between smokers and non-smokers in terms of response to excimer light. In conclusion, this study suggested that excimer light is useful for both initial regimen and suppression of exacerbation in treatments of PPP.