Peristomal pyoderma gangrenosum (PPG) is a rare dermatological condition associated with gastroenterological disease. Most gastrointestinal surgeons find it difficult to suspect and treat PPG, especially at early onset. The patient was an 18-year-old female. The patient underwent three-stage restorative proctocolectomy for refractory ulcerative colitis. On postoperative day (POD) 9, the trocar wound near the ileostomy site dehisced. Because the wound culture was positive, the wound was treated with an antibacterial agent as an infection. However, the wound worsened. The patient was referred to a dermatologist for diagnosis. PPG was diagnosed on POD 37. Wound management was initiated using topical steroids. The wound caused difficulties in pain and dressing management. Although infliximab was administered as a systemic therapy, it was discontinued because of allergic symptoms. Sealing therapy with hydrofiber dressing and adequate stoma pouching with stoma paste provided good exudate absorption and a clean environment by protecting the wound from stoma excretion. Oral prednisone was initiated on POD 82. Improvement in the wound condition was observed with a prednisone dose of 30 mg/day. Complete remission was achieved seven months after onset. Twelve months after the surgery, stoma closure was performed. The local cutaneous condition remained in remission without exacerbation. Suspicion of PPG can be difficult when it develops early after stoma creation. We never forget that PPG should be suspected when a progressive ulcerative lesion is found around the stoma, even early after operation. If PPG is suspected, a multidisciplinary team plays an essential role in its diagnosis and management.