SAEM Clinical Images Series: Leg Rash

This rash is consistent with ulcerative pyoderma gangrenosum (PG), a rare inflammatory condition which may occur in isolation or in association with systemic diseases. PG typically manifests as an erythematous nodule or pustule that progresses to form a purulent or necrotic ulcerative base. The lower extremities are the most frequently affected sites. In this patient, the presence of abdominal pain, hematochezia, and elevated inflammatory markers raises suspicion for an underlying diagnosis of ulcerative colitis. Measurement of fecal calprotectin may provide additional diagnostic support. Management of mild flares in an outpatient setting may include rectal or oral mesalamine (5-ASA) in combination with oral prednisone. Severe exacerbations often require hospitalization for systemic glucocorticoid therapy and gastroenterology consultation. The patient was started on IV glucocorticoids and during his admission had resolution of his rectal bleeding and improvement in his rash. Colonoscopy results confirmed the underlying diagnosis of ulcerative colitis. The patient was discharged in stable condition with outpatient gastroenterology follow-up.

Take-Home Points

• Pyoderma gangrenosum features erythematous nodules and pustules that progress to form a purulent or necrotic base, and is associated with inflammatory bowel diseases.

• Severe cases of PG generally require glucocorticoid therapy.