Does the minimal phototoxic dose after 8-methoxypsoralen baths correlate with the individual's skin phototype?

Background/Aims: Up to now no data have been available concerning whether t here is a significant correlation between skin phototypes and the minimum p hototoxic dose (MPD) after bath water delivery of 8-MOP. Methods: The skin phototype of each of 46 patients was determined based on the individual past history of solar-induced burning and tanning, In additi on, the MPD of each patient was assesed after photosensitization with a war m water bath (37 degreesC, 98.6 degreesF) containing 1.0 mg/l 8-methoxypsor alen (8-MOP). Statistical analysis was performed using a Mann-Whitney U-tes t and Spearman rank order correlation. Results: The median MPD in patients with skin phototype II was 2.0 J/cm(2) (range less than or equal to0.5 to greater than or equal to3.5) versus 1.5 J/cm(2) (range 1.0 to greater than or equal to3.5) in patients with skin ph ototype Ln. There was a considerable overlap between both groups. No signif icant difference was detected comparing both groups (P=0.7326) and Spearman rank order correlation revealed no correlation between skin phototype and MPD, Conclusion: Erythemal sensitivity in PUVA bath therapy, measured as MPD, is not correlated with sun-reactive skin phototype in skin types II and III. Thus skin phototype is not a suitable indicator for the initial UVA dose in PUVA bath photochemotherapy.