Ungual scabies mimicking periungual verruca in a patient with metastatic breast cancer treated with abemaciclib: a case report.

Ungual scabies is a rare manifestation of Sarcoptes scabiei infestation in nail units and may mimic other nail diseases, resulting in diagnostic delay. Herein, we report the case of a 58-year-old woman with metastatic breast cancer who received abemaciclib and presented with recalcitrant paronychia and verruca-like periungual hyperkeratosis, sparing the finger web area without pruritus. Skin biopsy confirmed multiple mites in the stratum corneum, resulting in the diagnosis of crusted scabies with nail involvement. Topical permethrin 5% cream and oral ivermectin were then administered. The prolonged unrecognized disease in our patient led to repeated visits to long-term care facilities and tertiary hospitals, thereby increasing the risk of nosocomial transmission. This case emphasizes that clinicians, including non-dermatologists, should consider scabies in patients with chronic periungual lesions, particularly in patients who are immunocompromised such as those using abemaciclib, to prevent hospital outbreaks and excessive healthcare costs.