INTRODUCTION
Pyoderma gangrenosum (PG) is a rare, idiopathic skin disease
that has been associated with a wide variety of disorders.
One to five percent of patients with inflammatory bowel disease (IBD) have PG.1 PG at the site of surgical ostomies is referred to as peristomal pyoderma gangrenosum (PPG). This variant is seen almost exclusively in patients that have underlying
IBD.2 These patients present clinically with ulcers that have well-defined, undermined, violaceous borders.2 Histopathological
confirmation of PPG is difficult due to nonspecific findings, and PPG therefore is a diagnosis of exclusion. We report a case of PPG successfully treated with topical crushed dapsone tablets.
CASE REPORT
A 27-year-old Caucasian male with a seven-year history of Crohn's disease and a six-year history of post-ileostomy biopsy proven PPG presented to our dermatology clinic for treatment of chronic ulcerative peristomal lesions. The patient's Crohn's disease
was well controlled with either 5 mg/kg infliximab infused every eight weeks or 40 mg adalimumab self-administered every
two weeks. Examination revealed a well-demarcated 6x4 cm ulcer at the periphery of the ostomy site. Previous treatments for the PPG included intralesional corticosteroid injections, 20 to 40 mg oral prednisone, and intermittent use of 25 to 100 mg oral dapsone daily for 34 months. The oral dapsone resulted in significant improvement in the PPG but was discontinued due to elevated transaminase levels (AST 76/ALT93). At that time, the patient had a 2.5x1.5 cm ulcer.
Based on the improvement with oral dapsone, the patient was begun on a regimen of 25 mg dapsone tablets self-crushed into a powder and then applied daily with ostomy dressing changes. The resulting powder did not prevent dressing adhesion;
this had been a problem with other attempted topical treatments. After one month of treatment, the lesion measured 1.5x1 cm (Figure 1). The patient's transaminase levels returned to normal and he continued treatment until total lesion resolution
six months later (Figure 2). At follow up five months after discontinuation of treatment, there has been no recurrence of his PPG (Figure 3).
DISCUSSION
Classical PG is a clinically diagnosed noninfectious skin disease in which pustules form and enlarge leaving ulcerative lesions with a necrotic margin. Cultures and biopsy are not diagnostic but may be used to rule out other conditions. PG possesses the property of pathergy, in which mild trauma results in development
of new lesions. In patients with an ostomy this occurs with relocation of the stoma or trauma to the skin around the stoma.1,2 As PPG is rare, misdiagnosis of PPG as an infection commonly delays the onset of appropriate treatment.
Fifteen to twenty percent of all patients with classic PG have IBD and almost all patients with PPG have IBD. Controlling the underlying disease is the initial step in treatment.2 Our patient's IBD was well-controlled with infliximab and adalimumab without resolution of his PPG. Wound care is important to prevent bacterial infection at the site. Maintenance of clean, dry, dressings
decreases risk of infection at ulcer sites.3
