Laser treatment of rosacea: a pathoetiological study.

OBJECTIVE To study the effect of laser treatment on rosacea, a common facial skin disease with symptoms of blushing, redness, telangiectasis, papules, pustules, and diffuse swelling of the skin, we focused on the stinging sensation and performed immunohistochemical evaluation of nerve density and neuropeptide expression. DESIGN Clinical investigation as well as the lactic acid (stinger) test was performed before and 3 months after the treatment with flashlamp pulsed dye laser, when skin biopsy specimens were also taken. SETTING University hospital. PATIENTS Thirty-two patients with rosacea, all with positive results from the lactic acid "stinger" test, were treated by flashlamp pulsed dye laser. MAIN OUTCOME MEASURES The biopsy specimens were taken from the stinger-positive areas in the nasolabial folds, fixed in Lanas fixative (10% formalin and 0.4% picric acid), and analyzed for the expression of protein gene product 9.5 (general nerve marker), substance P, calcitonin gene-related peptide, and vasoactive intestinal polypeptide, using a biotinylated streptavidin technique. RESULTS Thirty-one patients who were stinger positive before treatment showed decreased scores after treatment, and 1 patient had the same stinger test score before and after treatment. The number of protein gene product 9.5-positive fibers in the epidermis (P< .05) as well as the papillary dermis (P< .01) was decreased. This was also the case for substance P in the papillary dermis (P< .001), whereas no evident difference was noted for vasoactive intestinal polypeptide and calcitonin gene-related peptide. No difference was found for contact between nerves and vessels (factor VIII positive). CONCLUSIONS Laser treatment of rosacea that destroys small vessels has a good medical relevance because it reduces the unpleasant symptoms of the sensitive skin. A neurogenic etiology of stinging may be possible.