Permanent hair removal by normal-mode ruby laser
|Tytuł||Permanent hair removal by normal-mode ruby laser|
|Publication Type||Journal Article|
|Year of Publication||1998|
|Authors||Dierickx, C. C., Grossman M. C., Farinelli W. A., & R Anderson R.|
|Journal||Archives of dermatology|
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.
UNWANTED HAIR is a major cosmetic and surgical problem. Many temporary hair removal methods exist, including shaving, wax epilation, and use of chemical depilatories.1,2 Electrolysis is a well-established method for permanent destruction of terminal hair follicles. However, the method is tedious, and efficacy has been reported to range from 15% to 50% permanent hair loss.3 Scarring can occur after electrolysis, especially if inexpertly performed.4
Damage to hair follicles based on the theory of selective photothermolysis5 has been reported recently.6 Thirteen volunteers with brown or black hair were exposed to normal-mode ruby laser pulses (694 nm, 270 microseconds, 6-mm beam diameter) at fluences of 30 to 60 J/cm2 delivered to both shaved and wax-epilated skin sites on the thighs or back. In all 13 participants, laser exposures produced a hair growth delay consistent with induction of telogen. Ruby lasers have been commercialized for hair removal, but the question remains whether permanent hair loss can be induced by selective photothermolysis. Four study participants6 had clinically obvious hair loss at the final follow-up visit 6 months after exposure, each of these with less than 50% regrowth of terminal hairs. We decided to follow up the participants of this first study at 1 and 2 years after laser exposure to evaluate the permanence of hair removal.