ABSTRACT
Background: We report a severe hypersensitivity reaction due to warfarin in a COVID19 patient with sepsis. Case Report: An 86-year-old man was admitted for COVID19 pneumonia. He was vaccinated with 2 ComirNaty doses. He was affected by hypertension and CKD in emodialysis. At the admission he presented fever and tachypnea, the laboratory tests showed a septic state. We started administration of empiric therapy with piperacillina/tazobactam, it was replaced with meropenem and linezolid on the 29th day. After 10 days linezolid was stopped for thrombocitopenia. On the 14th day we prescribed warfarin for tromboembolic risk prevention when paroxysmal atrial fibrillation occurred . At the fifth week there was a clinic and laboratory worsening so we started target antibiotic therapy with cefiderocol and colistin due to positive blood cultures for A. Baumanii XDR. On the 24th day an inguinal erytema with blister-like lesion occurred and involved progressively face, neck, limbs, trunk and abdomen with extensive skin sloughing and crusted lesions appeared in the perioral and perinasal mucosa. Nikolsky sign was negative. Skin biopsy showed signs of inflammatory reaction. Warfarin was stopped and 1mg/kg methylprednisone was started with slow and progressive benefit. Conclusions: The patient has developed a warfarin linked hypersensitivity reaction with clinical features similar to toxic epidermal necrolysis. We assume that it was a borderline condition of hypersensitivity to warfarin in a patient with hyperactivation of immune system due to COVID19 and sepsis.