OBJECTIVES: Alopecia areata (AA) is a common autoimmune disease characterized by sudden patchy hair loss. Although a few treatments have been reported to have a beneficial effect, assessment of adverse events (AEs) in clinically controlled studies remains insufficiently established, thereby compromising the safety profiles of treatments. This targeted review aimed to quantify the most frequently reported AEs in clinical studies, including phase II, III, randomized controlled trials, and other prospective randomized studies for the treatment of AA.

METHODS: Study publications from the last 15 years (January 1, 2008 to December 31, 2022) were identified through targeted searches of the PubMed database and Google Scholar. Study titles and abstracts were screened, then study design details and data on AEs by treatment were extracted and checked for accuracy by two independent reviewers. Both systemic and topical treatments were considered. The five most frequently reported AEs that occurred in participants receiving treatment were recorded for analysis.

RESULTS: Sixteen clinical studies reporting AEs associated with four topical and 12 systemic therapies used in the treatment of AA were included. The most frequently reported AEs were headaches (n=213), nasopharyngitis (n=189), upper respiratory tract infections (URTIs; n=188), acne (n=151), and folliculitis (n=49). Two out of five most common AEs were dermatological and two respiratory. The most frequently reported AEs associated with systemic treatments were headaches, URTIs and nasopharyngitis, while for topical treatments, they were headaches, nasopharyngitis and pruritus, in order of frequency.

CONCLUSIONS: AA treatments are associated with high rates of AEs, particularly of dermatological and respiratory nature, which highlights the evident need for therapies with improved safety profiles. To this effect, conducting large-scale, double-blind, placebo-controlled clinical trials is of paramount importance to confirm the efficacy and safety profiles of therapies used in the treatment of AA, particularly as published literature in this area remains scarce.