A 56 year old woman presented with a 2 day history of multiple painless violet haemorrhagic lesions on her gums, tongue, and buccal mucosa (fig 1⇓). This was associated with gingival bleeding, but there was no relevant medical history of comorbidity, medications, or local trauma. She was diagnosed with multiple haemorrhagic bullae. Blood tests done using fluorescence flow cytometry (Sysmex ​XS-1000i, Sysmex Corp. Japan) showed a…