Objective: To assess the permanence of hair removal by normal-mode ruby laser treatment.
Methods: Hair removal was measured for 2 years after a single treatment with normal-mode ruby laser pulses (694 nm, 270 microseconds, 6-mm beam diameter).
Observations: Six test areas on the thighs or backs of 13 volunteers were exposed to normal-mode ruby laser pulses at fluences of 30 to 60 J/cm2 delivered to both shaved and wax-epilated skin. In addition, there was a shaved and wax-epilated control site. Terminal hairs were manually counted before and after laser exposure. Transient alopecia occurred in all 13 participants after laser exposure, consistent with induction of telogen. Two years after laser exposure, 4 participants still had obvious, significant hair loss at all laser-treated sites compared with the unexposed shaved and wax-epilated control sites. In all 4 participants, there was no significant change in hair counts 6 months, 1 year, and 2 years after laser exposure. Laser-induced alopecia correlated histologically with miniaturized, velluslike hair follicles. No scarring and no permanent pigmentary changes were observed.
Conclusions: Permanent, nonscarring alopecia can be induced by a single treatment with high-fluence ruby laser pulses. Miniaturization of the terminal hair follicles seems to account for this response.