Comparison study of a Q‐switched alexandrite laser delivered with versus without compression in the treatment of dermal pigmented lesions

Abstract

Purpura from Q-switched laser treatment in darkly pigmented skin is due to mechanical injury of blood vessels. It is well known that pressure 'diascopy' eliminates blood from cutaneous vessels by coapting the vessel lumen. In this study, we used pressure applied by a glass window on the Q-switched laser handpiece to remove cutaneous blood during laser exposure, making it possible to reduce purpura and dyspigmentation.