A pilot study to explore optimal interval between psoralen soak and UVA exposure

In the absence of controlled studies to provide a universally accepted protocol for the treatment of palmoplantar dermatoses with topical PUVA, phototherapy units throughout the U.K. have adopted protocols varying in the length of time-lapse between immersion and illumination, from 0 to 30 min. This study aims to determine whether the time-lapse affects the treatment outcome. If there is no difference between outcomes, this could have widespread implications in the time taken to treat patients and the number of patients that could be treated. This pilot study was a within-patient, randomized, assessment-blinded (i.e. single-blind), comparison of two treatment regimens in eight patients with eczema or psoriasis of either their hands/feet who have been referred for topical PUVA therapy. Two sites (either hands/feet) were be pretreated with topical psoralen. One site was then illuminated immediately with UVA light and the other site was illuminated 30 min after immersion. Assessments of symptoms (physician's global assessment, PGA) and a total lesion score comprising erythema, thickness, scaliness, fissures, pruritus/ pain, vesiculation and oedema were made by an independent assessor before the first treatment, then every 4 weeks throughout the treatment period and at the final visit. Photographs were taken at baseline and final visits. Eight patients (4 women and 4 men) were recruited for the study. Their ages ranged between 44 and 67 years (mean 52 years). One patient withdrew from the study. The remaining seven patients had phototypes as follows: two patients - skin type II, five patients - skin type III. Three patients had eczema and four patients had psoriasis affecting their hands/feet. The results show that patients with both hand/foot eczema and psoriasis improved during the course of treatment with regard to the total lesion score and PGA. One patient with eczema and one patient with psoriasis were clear by week 20. One patient with hyperkeratotic psoriasis affecting plantar sites felt there was a definite improvement when waiting for 30 min prior to illumination. However, the results indicate that there was no statistically significant difference in the total score and PGA between waiting for 30 min or immediate UVA illumination. The sample size was too small to draw statistically sound conclusions but strongly suggested immediate irradiation was generally suitable, except perhaps in hyperkeratotic conditions where the 30 min delay allowed perfusion to the viable epidermis. A larger patient cohort is now required for confirmation.