<h4>Introduction and importance</h4>Haemophilia A (HA) is a hereditary X-linked recessive hemorrhagic disorder that results from a deficiency or dysfunction of coagulation factor VIII (FVIII) caused by gene mutations.<h4>Case presentation</h4>This case report presents the challenging management of a 37-year-old man who developed perianal necrotizing fasciitis accompanied by severe infection, necrosis, and septic shock. Here, F8 is linked to infection.