Case of vemurafenib-induced Sweet's syndrome.

Vemurafenib is a targeted therapy that has become standard treatment for patients with advanced melanoma with a V600E BRAF mutation. It has been associated with frequent skin toxicity, including photosensitivity, rash and squamous cell carcinomas. We present an 83-year-old woman with an advanced V600E BRAF-mutant melanoma who developed a severe skin rash and fatigue after taking vemurafenib. The dose was reduced from 960 to 720 to 480 mg twice a day; however, she was subsequently admitted to the hospital with fever, chills, fatigue, confusion and a diffuse skin eruption. She then developed hypoxia and acute renal failure that required hemodialysis. A biopsy of her skin lesions revealed a neutrophilic dermatitis with papillary dermal edema, consistent with Sweet's syndrome. Her symptoms resolved upon discontinuation of vemurafenib and treatment with prednisone. This constellation of symptoms and clinical course are consistent with drug-induced Sweet's syndrome caused by vemurafenib.