Refractory pyoderma gangrenosum in Caucasian adolescent with Takayasu arteritis and life‐threatening infections

Pyoderma gangrenosum (PG) in Caucasians with Takayasu's arteritis (TA) is uncommon. We described a case of refractory PG in an 18-year-old Caucasian man with TA since the age of 10 and was treated with corticosteroids, methotrexate, anti-TNF therapy (adalimumab), anti-CD20 therapy (rituximab), cyclophosphamide and most latterly tocilizumab and leflunomide. He has vascular stenosis complicated with renovascular hypertension and is steroid-dependent. He presented with a 6-week history of a left cheek rapidly enlarging lesion associated with pain, bleeding and purulent discharge not responding to flucloxacillin. Incisional biopsy suggested PG. He later developed similar lesions on the volar aspect of the right hand and at venepuncture sites. Despite topical immunosuppressive medication and high-dose pulsed intravenous methylprednisolone, the left cheek lesion continued to grow rapidly. These painful, unsightly ulcers caused significant psychosocial stress and limited his daily life. Following a multidisciplinary team (MDT) discussion, tocilizumab was switched to abrocitinib. While initial improvement of lesions was observed, he subsequently developed an acneiform eruption which evolved into PG and became superinfected with herpes zoster virus and Staphylococcus aureus, requiring hospitalisation for intravenous (IV) acyclovir and antibiotics. Following several MDT discussions, abrocitinib was discontinued and a new regimen consisting of ciclosporin, dapsone and enhanced frequency IV immunoglobulin (IVIg) every 2 weeks was initiated, effectively stabilising his PG. This case highlights the rare association of PG and TA in Caucasians, the complexities of managing PG complicated by severe infections and underlying immunodeficiency, and the significant psychosocial burden of PG.