Several studies have been reported on the suppressive effect of ultrav
iolet B (UVB), UVA sunlight and PUVA on contact dermatitis. However, s
tudies that have tested the hypothesis that patch tests reactions have
a seasonal variation due to the suppressive influence of sunlight, ha
d found conflicting results. In order to clarify the influence of clim
ate conditions in Athens, Greece (sunlight, temperature, latitude 38-d
egrees) on patch tests results, data from 5468 patch-tested patients (
1978-1990) were analyzed for monthly, seasonal variation. In addition,
180 patients with a high degree of sun exposure due to occupation tha
t were prospectively re-patch-tested in a different season (i.e. summe
r versus winter), with the same allergens and technique, were studied
and analyzed statistically. Climate data was provided by the Hellenic
National Meteorological Service. The results indicate that there is no
significant influence on patch tests reactions in Athens, Greece. Thi
s may in part be due to the small differences in climate conditions th
at exist between summer and winter in Greece.