JAK inhibitors are known to be effective for some inflammatory scalp conditions including alopecia areata. Baricitinib for example is now FDA approved for treating alopecia areata.
There is some debate as to whether JAK inhibitors are helpful in androgenetic alopecia. Over the past few years, various researchers have been studying the role of various JAK inhibitors.
Casale et al 2022
Authors from the University of California, Irvine set out to analyze the clinical course of AGA in patients on JAK inhibitor therapy for inflammatory skin conditions. To do so, they retrospectively assessed hair loss in adult men at a single tertiary center who were treated with an oral JAK inhibitors for at least 24 weeks for various indications.
Patients stayed on a constant dose of the JAK inhibitor and did not use other medications for hair loss. Clinical photographs were assessed for AGA severity utilizing the Hamilton Norwood (HN) scale) every 12 weeks for the duration of treatment.
There were 18 men included in the study (average age 40.9 years, range 20–71). Average duration of treatment was 66 weeks (range 24–100 weeks). Patients were on various types of JAK inhibitors. 14 were using for JAK inhibitors for alopecia areata (10 on JAK1/JAK2 inhibitor and 4 on JAK 3 inhibitor) and 4 were using for inflammatory skin disease like vitiligo, atopic dermatitis including 1 using JAK 1 inhibitor and 3 using JAK 3 inhibitors).
All patients with alopecia areata had an improvement in alopecia areata with the JAK inhibitors. However, none of the patients had an improvement in the Hamilton Norwood scale indicating no improvement in the androgenetic alopecia component. No patient seemed to have a worsening of their Hamilton Norwood scale.
This is a nice study and helpful to all those who wonder about the potential of JAK inhibitors to help AGA. All in all, the authors felt that JAK inhibitors don’t seem to help androgenetic alopecia. They state that they can’t completely rule out that these medications don’t help prevent hair loss but the study doesn’t really allow this to be answered.
This is an interesting study albeit a small study. It can be challenging to evaluate AGA admixed with alopecia areata sometimes so this study is challenging. This study evaluates Hamilton Norwood balding scales which is a lot less sensitive than up close monitoring follicular hair counts. Nevertheless, monitoring global hair loss is probably the ideal way to go about studying is JAK inhibitors help AGA. This study suggests that this is not likely to be a key method for treating AGA with current JAK inhibitors.
Casale F et al. Are Janus kinase (JAK) inhibitors beneficial in the treatment of androgenic alopecia? Int J Dermatol. 2022 Nov;61(11):e457-e458.