ABSTRACT:

Objective:

To examine the clinical, histological and immunohistological effects of flashlamp photoepilation.

Design:

Nonrandomized control trial with blinded histological study and follow-up of 1 to 20 months.

Setting:

Private academic practice.

Subjects:

Sixty-seven subjects (10 males and 57 females) with areas of excess body hair.

Interventions:

Single (9 subjects) or multiple (58 subjects) treatments (noncoherent, 590-1200 nm, 2.9-3.0 milliseconds, 40-42 J/cm2) to hairy skin. From subjects given a single treatment, biopsy samples were taken immediately after treatment and at different intervals for up to 20 months.

Mean Outcome Measures:

Clinical measures include hair counts and morphologic features before and after treatment. Histological measures include terminal-vellus and anagen-other ratios, hair shaft diameter, and morphologic features (routine and immunohistochemical detection of bcl-2, bax, p53, Ki67, cyclin D1, and hsp70) before and after treatment.

Results:

Mean hair loss after photoepilation was 49%, 57%, and 54% for a single treatment and 47%, 56%, and 64% for multiple treatments at follow-up of less than 3 months, 3 to less than 6 months, and 6 months or longer, respectively (P<.05 for all comparisons). Transient erythema was seen in all subjects; no scarring occurred. Histologically, treatment caused morphologic damage confined to hair follicles and shafts. Terminal vellus and anagen-telogen ratios, mean hair shaft diameter, and immunohistochemical profiles were not significantly modified by treatment. Treatment did not alter other skin adnexa, epidermis, or vessels.

Conclusions:

Flashlamp treatment leads to significant, long-lasting epilation. The predominant mechanism seems to be via selective photothermal damage to large, pigmented hair follicles rather than induction of a programmed state of follicular cycle arrest or follicular miniaturization.