Toxic epidermal necrolysis (TEN) is a rare, acute life-threatening mucocutaneous disorder that is characterised by epidermal loss/exfoliation exceeding 30% total body surface area (TBSA) and is on a spectrum that includes erythema multiforme and Stevens–Johnson syndrome (SJS). It is estimated that 80% of TEN cases are related to medication reactions; the association based on the recognition that TEN usually develops 1–3 weeks following administration of the suspect drug. It is agreed that primary treatment consists of prompt withdrawal of causative drugs and transfer to a regional burn unit. Transfer to a burn unit, no more than 7 days after onset of symptoms, has been acknowledged as reducing the risk of infections, hospital length of stay and infection-related mortality. Due to the uncertainty surrounding TEN pathogenesis, several different modalities have been proposed for the treatment of TEN, including high-dose intravenous immunoglobulins, plasmapheresis, cyclophosphamide, cyclosporine and systemic steroids; however, these therapies are relatively ineffective. The use of systemic corticosteroids for treatment of TEN has in particular been deemed controversial due to associations with increased infections leading to greater length of hospital stay and increased mortality. Granulomatosis with polyangiitis (GPA), formerly known as Wegener’s granulomatosis, is a rare relapsing-remitting disorder of unknown aetiology, characterised by granulomatosis inflammation and necrotising vasculitis predominantly affecting small- to medium-sized vessels. While a 5-year survival rate of 75–83% is now realised, relapse and associated morbidity is of concern. The established treatment for GPA follows the recommendations of the French National Authority for Health (HAS) for systematic necrotising vasculitis. With induction treatment, it is recommended that GPA be treated with a combination of systemic corticosteroids and immunosuppressants. A review of the literature failed to identify any previous case where both of these conditions coincide. Our search was conducted through databases which included MEDLINE, PubMed, Scopus, AMED, CINAHL and EMBASE, using keywords: toxic epidermal necrolysis, Wegener’s granulomatosis, granulomatosis with polyangiitis. We submit the rare case of a 22-year-old woman who presented to our regional burn unit with both GPA and TEN, and we discuss the presentation, investigation and multidisciplinary management of the patient, as well as reviewing the literature regarding these two conditions., Lay Summary Toxic epidermal necrolysis is a potentially fatal condition where there is a large area of skin exfoliated after the body’s reaction to a particular medication. Its treatment is largely by stopping the medication that is thought to have caused this reaction and also by regular dressings, thus keeping the area clean from any infection. Granulomatosis with polyangiitis, also known as Wegener’s granulomatosis, is another potentially fatal condition. Its treatment is very specific; however, this treatment may be harmful to a patient with toxic epidermal necrolysis. We describe the management of a patient who presented with both conditions, which is an extremely rare event. We describe the diagnosis and treatment during the patient’s inpatient stay at a regional burns unit. From this case report we have shown insight into the multidisciplinary management needed to manage such a complex patient, who made a full recovery.