PIGMENTARY CHANGES AFTER PULSED DYE-LASER TREATMENT IN 125 NORTHERN EUROPEAN PATIENTS WITH PORT-WINE STAINS

We investigated the occurrence of pigmentary changes after flash lamp pumped dye laser treatment in 125 Norwegian patients. Post-treatment h yperpigmentation occurred with equal frequency during summer and winte r (23%), and the facial regions did not exhibit higher occurrence than lesions located elsewhere. The patients that achieved hyperpigmented skin were not exposed to any higher fluence than those without this co mplication. On the contrary, we found that during the summer period fr om April to September the patients with post-treatment hyperpigmentati on had been exposed to a significantly lower dose than those without p igmentary changes. These results indicate that the epidermal melanin c ontent is not the only criterion for obtaining post-treatment hyperpig mentation. There might also be a constitutional disposition. In predis posed individuals the threshold dose for hyperpigmentation might be re duced in summer when the skin is more pigmented.