In January 2016, Palmer-Tomkinson was diagnosed with a prolactinoma, a benign tumour (adenoma) of the pituitary gland, and announced her illness publicly in November of that year. Prolactinomas are non-malignant, and treatment was successful. She also suffered from ANCA Associated Vasculitis. On 8 February 2017, Palmer-Tomkinson was found dead at her home in London. The death was treated as unexplained but not suspicious. Her sister later told the media that the cause of death was a perforated ulcer and peritonitis.