The effect of cutaneous prostaglandin application on nail growth, nail brittleness, and intraocular pressure

Background: Bimatoprost has known adnexal activity and was observed to increase nail growth at two clinical centers. Objectives: In this randomized, double-blinded, placebo-controlled pilot study, we examine the effect of bimatoprost (Lumigan 0.01%), applied bid to the proximal nail fold on nail growth, nail brittleness, and intraocular pressure. Methods: Bimatoprost drops were placed on the proximal nail folds of 45 subjects on one hand (medication group) and vehicle drops to the other hand (control group). Baseline and final nail growth measurements, Goldmann applanation tensions of both eyes, and photos at 30 days were performed. Nail brittleness was subjectively graded. Results: For the 38 subjects completing the study, the final mean nail growth of the hands, the net individual nail growth of the digits (excluding chipped nails), nail brittleness, and eye pressure readings were NS at P<.05. Photos revealed no increased hirsutism, but one subject with increased skin pigmentation. The drops were well tolerated without adverse effects. Nail chipping was a limitation of the study. Conclusions: Despite the negative results in this pilot study on nail growth and brittleness, further studies with higher bimatoprost concentration (0.03%) are warranted. We recommend monitoring nail growth by etching or marking the nail rather than measuring the full nail length due to our chipped nail findings.