Pili Bigeminy Induced by Low Fluence Therapy with Hair Removal Alexandrite and Ruby Lasers

Abstract

To our knowledge, this is the first report of pili bigminy as a complication of laser-assisted hair removal.

Photo‐epilation: Guidelines for care from the European Society for Laser Dermatology (ESLD)

“…I have seen such complications in three of my patients (2) and it has been reported previously by other authors using different types of lasers (3)(4)(5)(6). If a low fluence laser is used for hair removal it may not be strong enough to destroy the hair follicles, with possible dissemination of energy reaching the hair bulbs where, instead of destroying them, it actually might induce the keratinocytes with the properties of the stem cells to proliferate, leading to the appearance of pili bigemini and possibly the paradoxical increase in hair density and thickness in the treated areas, giving the appearance of hirsutism (3).…”

Pili bigemini complicating diode laser hair removal

“…According to the authors, ‘… dissemination of energy reaching the hair bulbs … actually might have induced the keratinocytes with the properties of the stem cells to proliferate in such a way that … they proliferated as twins. These keratinocytes with stem cell properties are concentrated below the midpoint of the hair follicle and outside the hair “bulb”’ 15 . This thesis seemed to be confirmed by the fact that the phenomenon of pili bigemini did not occur after the third therapy, in which it was possible to use higher fluence (over 30 J/cm 2 ).…”

“…This phenomenon was described as pili bigemini by Ye et al . in the article entitled ‘Pili bigemini induced by low fluence therapy with hair removal alexandrite and ruby lasers’ 15 …”

Hair Growth Induced by Diode Laser Treatment

“…Localized hypertrichosis has been reported following interferon treatment, 15 fractures with casting, 10–13 and topical corticosteroid use 14 ; in sites of venous incompetence 14 ; and postoperatively 8 . Low‐energy laser treatment for hair removal has also resulted in pili bigeminy, or two hair shafts emerging from the same follicular orifice 16 . Localized hair growth following laser treatment and other stimuli illustrates the complex mechanisms surrounding the hair growth cycle.…”

“…8 Low-energy laser treatment for hair removal has also resulted in pili bigeminy, or two hair shafts emerging from the same follicular orifice. 16 Localized hair growth following laser treatment and other stimuli illustrates the complex mechanisms surrounding the hair growth cycle. The current case demonstrates dramatic hair growth following laser treatment for hair reduction and a less than average response to hair laser treatment in another site.…”