Dermographic Urticaria Induced by Long-Pulsed Diode Laser-Assisted Epilation: Rare Etiology of a Common Eruption

This document reported a rare case of dermographic urticaria induced by an 810 nm long-pulsed diode laser used for hair removal in a 36-year-old woman. The patient developed linear, erythematous, mildly itchy wheals shortly after laser treatment, which subsided spontaneously within 2 hours. The urticaria recurred in subsequent sessions but was prevented by taking levocetirizine 5 mg before each session. The exact cause of urticaria following laser epilation was unknown, but it was suggested that the laser might trigger dermographic urticaria through local mast cell degranulation. The patient remained free from urticaria 6 months after the last laser session.