So, I Thought This Was Interesting … Tofacitinib Grows Hair!

In my practice, I have a number of patients taking tofacitinib for their rheumatoid arthritis. I came across an interesting potential new use for tofacitinib. This medication can result in significant hair growth in patients with alopecia totalis, alopecia universalis, and alopecia areata.

A study of hair cycling in mice demonstrated that JAK signaling induces a telogen block that prevents the hair follicle from entering the anagen (growth) phase. JAK inhibitors can block this JAK signaling and induce anagen hair growth. Furthermore, up-regulation of pSTAT1 and pPSTAT3 signaling in hair follicles is seen in alopecia areata but not in normal hair follicles.

There are a number of case reports and case series in PubMed. The largest study is from Stanford University, which performed an open-label trial of tofacitinib involving 66 patients. In this trial, 32% of individuals experienced a 50% improvement in hair growth after just 12 weeks of treatment. However, hair growth stopped 8 weeks after discontinuation of the drug. If a patient consented to a scalp biopsy, the presence of peri-bulbar inflammation was very predictive of hair growth. A shorter duration of disease was also predictive of hair growth.

It is important to note that patients taking tofacitinib without autoimmune hair loss will not grow hair. The efficacy of tofacitinib in hair growth is limited to those with an autoimmune/inflammatory cause of hair loss (i.e. tofacitinib likely won't work for male pattern baldness). There is now a topical form of tofacitinib in clinical trials for alopecia.

More reports from ACR 2016