Acitretin-Induced Poliosis With Concurrent Alopecia

patient, the poliosis resolved when acitretin was discontinued and repigmentation to the patient's original black hair color occurred over two-four months.

The mechanisms by which retinoids induce hair changes are not well understood. Retinoids are thought to cause telogen effluvium through shortening of the telogen phase resulting in premature detachment of club hairs from their follicles.⁷ Another mechanism, termed immediate anagen release telogen effluvium, involves shortening of the anagen phase resulting in premature entry into the telogen phase. In our patient, the time from insult to hair loss and subsequent re-growth was three months, which reflects the average time of a normal telogen phase.^8,9 Although clinically subtyping telogen effluvium is difficult, we postulate our patient likely experienced a drug-induced immediate anagen release telogen effluvium. Additionally, a negative pull test, as seen with our patient, is often associated with shortened anagen phase telogen effluvium.⁹

Although there are no proposed mechanisms for acitretin-induced poliosis, it is possible that it may be a result of the immunomodulatory effects of the drug. Acitretin may affect melanocyte stem cells and/or lead to loss of differentiated melanocytes at the hair matrix causing depigmentation.¹⁰ Closer examination of retinoid-induced hair changes is needed in order to help physicians better counsel their patients regarding adverse effects and to expand the current knowledge on hair follicle biology.

The authors have no relevant conflicts of interest to disclose.