Rebound Effect Associated with JAK Inhibitor Use in the Treatment of Alopecia Areata

The letter to the editor discusses the potential rebound effect of hair loss following the discontinuation of Janus kinase (JAK) inhibitor treatment in patients with alopecia areata (AA), an autoimmune disease characterized by non-scarring hair loss. The authors present two cases: a 48-year-old female treated with topical ruxolitinib who experienced a severe rebound from 7% to over 99% Severity of Alopecia Tool (SALT) score three months post-treatment, and a 44-year-old female treated with oral tofacitinib who went from a 25% to 90% SALT score six weeks after stopping treatment. This rebound effect not only involved the loss of regrown hair but also a worsening of the patient's baseline alopecia. The authors suggest that this could be due to increased disease activity, a telogen effluvium, or an organ-level quorum-sensing effect. They note that this is the first report of a rebound worsening and that it is unclear if this effect is associated with all JAK inhibitors or if it can be mitigated by specific ones.