Allergic Contact Dermatitis from Minoxidil

In the document from 1988, the authors reported on the development of allergic contact dermatitis in four patients treated with topical Minoxidil for common baldness. The patients had been using Minoxidil at concentrations of 2% for three patients and 3% for one patient, compounded with propylene glycol, distilled water, and alcohol. The adverse effects, which included eczematous reactions and pruritus, appeared within 4 months to 1 year after starting the treatment. Patch testing with Minoxidil at 1% and 2% in alcohol and propylene glycol at 4% and 20% in water showed positive results for Minoxidil in all patients, while control tests in 20 volunteers were negative. The authors concluded that allergic contact dermatitis to Minoxidil is likely to become more common, which is concerning for patients seeking treatment for baldness.