Does the minimal phototoxic dose after 8-methoxypsoralen baths correlate with the individual's skin phototype?
OBJECTIVE
Up to now no data have been available concerning whether there is a significant correlation between skin phototypes and the minimum phototoxic 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 addition, the MPD of each patient was assesed after photosensitization with a warm water bath (37 degrees C, 98.6 degrees F) containing 1.0 mg/l 8-methoxypsoralen (8-MOP). Statistical analysis was performed using a Mann-Whitney U-test and Spearman rank order correlation.


RESULTS
The median MPD in patients with skin phototype II was 2.0 J/cm2 (range < or =0.5 to > or =3.5) versus 1.5 J/cm2 (range 1.0 to > or =3.5) in patients with skin phototype III. There was a considerable overlap between both groups. No significant difference was detected comparing both groups (P=0.7326) and Spearman rank order correlation revealed no correlation between skin phototype and MPD.


CONCLUSIONS
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.
Schiener
R
R
Department of Dermatology, University of Ulm, Germany.
Behrens-Williams
S C
SC
Pillekamp
H
H
Peter
R U
RU
Kerscher
M
M
D003627:Data Interpretation, Statistical; D005363:Ficusin / Q000627:therapeutic use*; D006801:Humans; D008730:Methoxsalen / Q000627:therapeutic use*; D010778:Photochemotherapy; D012871:Skin Diseases / Q000188:drug therapy* / Q000473:pathology; D018709:Statistics, Nonparametric
D005363:Ficusin; D008730:Methoxsalen