Onychopathy Induced by Nivolumab: A Targeted Immunotherapy.

Nivolumab is a human immunoglobulin G4 (IgG4) monoclonal antibody that binds to the PD-1 receptor on T-cells and blocks its interaction with PD-L1 and PD-L2, releasing the PD-1 pathway-mediated inhibition of the immune response, including the anti-tumor immune response, resulting in decreased tumor growth. Here, we present a case of a 56-year-old lady with a diagnosis of squamous cell carcinoma (SCC) of the lip who presented with dystrophy of 20 nails, distal onycholysis, yellow-black discoloration of nail plates, painful paronychia with superimposed bacterial infection of big toes of both feet for three months. Few warty growths were also appreciated on big toes of both feet. She had undergone for her SCC 33 sessions of radiotherapy and 43 cycles of nivolumab 140mg for 60 minutes every two weeks. Following discontinuing this drug, the peri-ungual and nail bed inflammation improved, however nail plate dystrophy persisted. To our knowledge, the occurrence of nail dystrophy with nivolumab has never been reported before but it has been described with other targeted therapies.