The effects of heating and cooling on ultraviolet radiation‐induced erythema and pigmentation in human skin

BACKGROUND/PURPOSE: As most biochemical systems are affected by temperature, thermal changes before or after ultraviolet (UV) irradiation could influence skin vascular blood flow changes and inflammatory responses. In this study, our aim was to investigate the influence of thermal changes on UV-induced acute skin reactions, namely, erythema and pigmentation. METHODS: Our volunteers consisted of 10 males, with ages ranging from 22 to 24 years and with Fitzpatrick's skin type III or IV. Skin temperatures were changed with a 45 degrees C heating pad or by ice pack application before or after UV irradiation (control, 1 minimal erythema dose (MED), 2 MED) and then changes in erythema and pigmentation were measured by a Minolta Spectrophotometer CM-2002. RESULTS: The present study demonstrates that both heating and cooling increase skin erythema and reduce pigmentation, and that the timing of heating and cooling influences the UV-induced skin reaction. Pre-heating and post-cooling groups showed more UV-induced erythema than the post-heating and pre-cooling groups, respectively. CONCLUSION: Our results indicate that alteration of skin surface temperature could modulate UV-induced erythema and pigmentation responses.