Laser hair removal affects sebaceous glands and sebum excretion: A pilot study

Background: During laser-assisted hair removal, sebaceous glands closely as sociated with hair Follicles might also be affected. Objective: We investigated the effect of the long-pulsed ruby laser on seba ceous glands. Methods: Sebum excretion rates (SERs) of 16 subjects were measured quantita tively by means of sebum-absorbent tape and analyzed by means of image anal ysis techniques on laser-treated sites, compared with adjacent untreated ar eas. Evaluation was done at an average of 9 months (range, 4.5 to 12 months ) after the last treatment. Histologic examinations were performed on 3 rep resentative subjects before treatment, immediately after treatment, and 9 m onths after the last treatment. Results: Significant increases in SERs were observed in 11 of 16 subjects ( 68.75%). Three subjects (18.75%) showed lower SERs, whereas 2 subjects (12. 5%) demonstrated no difference in SERs between treated and untreated areas. Biopsy specimens showed an apparent reduction in sebaceous gland size. Spe cimens taken immediately after laser irradiation revealed sporadic damage t o sebaceous glands. Conclusion: In some patients a variable but statistically significant incre ase in sebum excretion occurs ii to 12 months after ruby-laser hair removal treatment at high fluences. A reduction in sebaceous gland sizes on laser- treated areas was observed. We hypothesize that decreased resistance to seb um outflow may explain this result, following miniaturization or absence of hair shaft after ruby laser treatment. Further study is needed to assess m echanisms for this interesting response.