[Side effects and risks of phototherapy].

Interference factors of UV-therapy are among others the absolutely unknown biological activities of visible and ultra red wavelengths, which represent the main part of the energy emitted from all UV-sources. They produce a rise of the skin surface temperature up to 42-44 centigrades immediately followed by a reticulate erythema as well as a proliferative response of basal cells, which goes synchronously with that after SUP or UVA application but does not result in hyperproliferation. Acute side effects are direct toxic activities of UV-light with sunburn, up to severe bullous reaction, but without scarring; exacerbation of UV-sensitive dermatoses, internal diseases, and modulations of the immune system.