A 28-year-old Caucasian female presented with a two-month history of low-grade fevers, abdominal cramps, occasional bloody stools, weight loss, high C-reactive protein (234 mg/L), and with a newly-onset painful bullous skin change on the right hand (Fig. 1A). Her prior medical history included inflammatory bowel disease (IBD) successfully managed with peroral mesalazine. At the current admission, broad spectrum antibiotics (meropenem and vancomycine) were empirically started; however, the fever persisted, the blood and stool cultures were repeatedly negative, as was the skin swab.