The Use of Phosphodiesterase Inhibitors for the Treatment of Alopecia

The document from April 2020 reviews the effectiveness of phosphodiesterase inhibitors (PDEi) like caffeine and apremilast in treating alopecia. It includes 15 articles, with studies showing that topical caffeine at concentrations of 0.2%-2.5% has promising results for androgenetic alopecia (AGA) and telogen effluvium (TE), with minimal adverse events, although these studies were small and single-centered. Injectable caffeine also showed high patient satisfaction and significant hair regrowth for AGA. However, for alopecia areata (AA), the results were less promising; a randomized controlled trial with 30 patients showed limited success with oral apremilast, with no significant difference in efficacy compared to placebo and some patients discontinuing due to side effects. Case reports indicated some success with apremilast for individual AA patients. The document concludes that while there is potential for PDEi, especially caffeine, in treating hair loss, more extensive research is needed to confirm efficacy and determine optimal dosing.