Ruxolitinib Found to Cause Eyelash Growth: A Case Report

In a 2017 case report, a 77-year-old Asian man with hypereosinophilic syndrome (HES) exhibited unexpected eyelash growth after treatment with ruxolitinib, an oral Janus kinase inhibitor. The patient, who did not respond to other medications, noticed his eyelashes becoming longer and thicker several months into the ruxolitinib treatment, with no hair growth on other body parts. This was the first report of eyelash growth associated with ruxolitinib, leading the authors to suggest that Janus kinase inhibitors might promote eyelash growth and could be investigated as a treatment for madarosis, the absence of eyelashes. The case underscores the potential side effect of eyelash growth from these drugs and their possible use in hair loss conditions.