Paradoxical hypertrichosis and terminal hair change after intense pulsed light hair removal therapy.

BACKGROUND: Although complications such as blister formation, erosion, and post-inflammatory hypo- and hyperpigmentation are well-known side effects of intense pulsed light (IPL) photoepilation, little is known about the paradoxical hypertrichosis after therapy.

OBJECTIVE: To report the paradoxically increased hair density and coarseness after IPL photoepilation.

METHODS: Within a period of 23 months, a total of 991 hirsute female patients were treated with IPL for photoepilation. The IPL system used was the Vasculight-SR, a multifunctional laser and IPL system (Lumenis Inc., Santa Clara, CA, USA). The cut-off filters frequently used were 695, 755 and 645 nm.

RESULTS: Paradoxical hypertrichosis and terminal hair change were detected after a few sessions of IPL therapy among 51 out of 991 patients. Our serial digital photographs, schematic diagrams, and hair counts before and after treatment confirmed the patients' claims. The other more commonly seen complications were epidermal burning with blisters, erosion, and crust formation followed by post-inflammatory hypo- and/or hyperpigmentation.

CONCLUSION: Paradoxical hypertrichosis and terminal hair change is a common complication of IPL photoepilation.