Abemaciclib-Associated Skin, Hair, and Nail Toxicities: A Case Report.

Abemaciclib is a cyclin-dependent kinase 4/6 inhibitor that is utilized to manage hormone-sensitive human epidermal growth factor receptor-2 positive metastatic breast cancer. Palbociclib and ribociclib are types of other orally administered CDK4/6i that share similar safety and tolerability compared with Abemaciclib. Reported side effects include reversible neutropenia of a lower grade, gastrointestinal toxicity, and anemia. CDK4/6i could induce dermatological side effects. Although less frequent, cutaneous adverse effects of CDK4/6i account for 25% of medication discontinuation. Frequent cutaneous adverse events are rash and pruritus; nonetheless, hair loss, nail changes, vitiligo, and photosensitivity reactions, were also reported to a lesser extent. Herein, we report a case of hair, nail, and pigmentary disorder that occurred 10 months after initiating abemaciclib treatment.