A case of trichodysplasia spinulosa related to ruxolitinib treated successfully with oral acitretin.

Trichodysplasia spinulosa (TS) is a rare disease that affects immunocompromised patients, characterized by hair-like growths caused by TS-associated polyomavirus infection. Little is known about specific immunosuppressive drugs that can precipitate the condition. We report a case of TS presenting after initiating the oral Janus-associated kinase inhibitor (JAKi) ruxolitinib. A 67-year-old female with a history of allogeneic bone marrow transplant requiring immunosuppression with tacrolimus, prednisone and, more recently, ruxolitinib 5 mg twice daily due to Graft versus Host Disease presented to the clinic with a facial rash. The clinical and histopathological findings in the setting of immunosuppression were consistent with TS. Initial treatments were ineffective, but oral acitretin showed significant improvement after 3 months. Due to the close temporal relationship between the initiation of ruxolitinib and the development of TS, this case suggests that JAKis may contribute to TS development by suppressing the JAK-signal transducer and activator of the transcription pathway's antiviral functions.