Seasonal influence on patch test results in Greece

Several studies have been reported on the suppressive effect of ultraviolet B (UVB), UVA sunlight and PUVA on contact dermatitis. However, studies that have tested the hypothesis that patch tests reactions have a seasonal variation due to the suppressive influence of sunlight, had found conflicting results. In order to clarify the influence of climate conditions in Athens, Greece (sunlight, temperature, latitude 38 degrees) 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 that were prospectively re-patch-tested in a different season (i.e. summer 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. This may in part be due to the small differences in climate conditions that exist between summer and winter in Greece.