She did, however, have a 12-year history of Crohn’s disease, which was treated with infliximab for 3 years; she had been off therapy for about 3 years. Her most recent colonoscopy showed no active disease and she had no family history of autoimmune disorders.
The patient had a level of C-reactive protein that was 6.44 mg/dL, an erythrocyte sedimentation rate or 30 mm/h, a total leukocyte count of 12 × 109/L (76% neutrophils), and a hemoglobin level of 11.6 g/dL. She tested negative for extractable nuclear antigens, anti-neutrophilic cytoplasmic antibodies, anti-ds DNA, complement C3 and C4, rheumatoid factor, and anti–cyclic citrullinated peptide antibodies. Transthoracic echocardiogram ruled out endocarditis, and magnetic resonance imaging of hands did not support a diagnosis of osteomyelitis.
The patient was treated with debridement and evacuation of subungual fluid collections by trephination. She was discharged from the hospital with a prescription for oral cephalexin. However, 2 days later, her pain and swelling markedly worsened, and she was hospitalized again.
The nail on her right middle finger was surgically lifted, revealing irregular, boggy ulcers with violet borders surrounding a purulent, necrotic base. Biopsy analysis of the nail bed showed nonspecific inflammatory changes but an epithelial infiltrate composed of neutrophils and lymphocytes with necrotic debris and abscesses. The subepithelial stroma had neutrophilic vasculitis and vessel destruction. The authors could not culture any aerobic, anaerobic, fungal, or mycobacterial organisms.
Based on the patient’s history of Crohn’s diease and clinical analyses, the authors made a diagnosis of pyoderma gangrenosum. The patient began oral prednisone therapy (40 mg/day), and her symptoms disappeared after 1 week. The dose was gradually tapered and then stopped, and the nail lesions did not return.
The authors explain that pyoderma gangrenosumis a rare but serious cutaneous manifestation reported in approximately 0.7% of patients with Crohn’s disease. The lesions develop predominantly in lower extremities and peristomal sites, but rarely in the hands. It was also unusual that the patient’s Crohn’s disease was in deep remission.
Inayat and Hurairah explain that a diagnosis of pyoderma gangrenosumis can be made only following exclusion of other disorders, and relies on consistent clinical and histopathologic findings. Sweet’s syndrome and leukocytic vasculitis are its close differentials.