Contact dermatitis in reaction to 2% topical minoxidil solution

The article discusses the incidence of cutaneous side effects in patients using topical minoxidil solution for hair loss treatment. The study involved 161 patients with common baldness, both men and women, who were entered into double-blind, placebo-controlled trials of topical minoxidil 2% solution. Of the 161 patients, 12 (7.5%) had irritant dermatitis sufficient to require discontinuation of treatment and 6 (3.7%) had allergic contact dermatitis. The results indicate that cutaneous reactions to topical minoxidil solution are an important side effect, and the incidence is considerably more common than that quoted on the data sheet for minoxidil solution in the United Kingdom. The article also discusses the importance of the vehicle in which minoxidil is tested and suggests that the tissue penetration gained with organic bases is important not only for demonstrating contact sensitivity but also for producing adequate tissue levels for an effect on the hair follicle.