RESUMEN
OBJECTIVE: Hirsutism is the presence of excess terminal hairs in females in a male-like pattern. The most accepted hypothesis for the development of hirsutism is increased 5α-reductase activity in hair follicles of hirsute women. Finasteride partially blocks the conversion of testosterone to dihydrotestosterone through inhibition of 5α-reductase in hair follicles. This study was designed to determine the efficacy of finasteride gel 0.25% in management of idiopathic hirsutism and treatment of hirsutism with topical finasteride to lessen the side-effects. METHODS: Women after puberty that have idiopathic hirsutism criteria are divided randomly in two groups; treatment and control. The number of patients in each group is 15 and received finasteride and placebo gel once a day on their skins. The patients were visited every month by a dermatologist and the amount of response to the treatment and the patient satisfaction was recorded. Ferriman-Gallwey score of the treated area was determined. RESULTS: After 6-months, mean thickness hairs in treating group were decreased from 102.00 ± 9.58 µm to 86.4 ± 11.4 µm (p < 0.05), this difference was statistically significant. Gel application did not indicate any type of side-effects. LIMITATIONS: Inclusion and exclusion criteria. CONCLUSION: Finasteride partially blocks 5α-reductase. Because of the good absorption through the skin and good solubility of this medicine, the prepared gel formulation applied on the hirsutism area showed a significant decrease in hair growth locally, so finasteride gel is an efficient and harmless therapy in patients with idiopathic hirsutism.