Skin Lesions and Neutropenic Fever in a 69-Year-Old Woman

Cameron Nichols, MD; Fnu Nutan, MD


June 26, 2020

Erythema multiforme can look similar to Sweet syndrome, especially when on the lower extremities, but erythema multiforme classically has a more targetoid appearance. Pyoderma gangrenosum should also be considered, but its features include rolled gray borders and an edge that hangs over an ulceration. Leukemia cutis can be difficult to differentiate, but it typically has a more violaceous appearance. It is best distinguished by biopsy.

Sweet syndrome may also have systemic manifestations. Manifestations that are more common include fever, leukocytosis, arthralgias, arthritis (favors knees and elbows), myalgias, and ocular involvement (usually conjunctivitis). Less common manifestations include renal involvement, acute myositis, hepatitis, neutrophilic alveolitis (cough, dyspnea, pleurisy), and aseptic meningitis.[1]

Histopathologic findings from a skin biopsy help elucidate a diagnosis of Sweet syndrome. The characteristic finding is neutrophilic infiltration without signs of vasculitis. This finding can also be seen in many infections, so obtaining tissue cultures to rule out infection is important. Histopathologic variants include histiocytoid and lymphocytic Sweet syndrome, as well as giant cellulitis-like and necrotizing fasciitis-like morphologies. Whether or not differing pathologic findings correlate with different underlying causes or disease manifestations is unclear.

The diagnostic criteria for Sweet syndrome require two major criteria and two of four minor criteria.[2] Major criteria include:

  • Typical skin lesions: Abrupt onset of painful edematous erythematous plaques and nodules

  • Typical histopathologic findings: Sterile collection of neutrophils without evidence of leukocytoclastic vasculitis

Minor criteria include:

  • Fever

  • Excellent response to steroid therapy

  • Association with cancer (especially hematologic), inflammatory disease, pregnancy, or preceding infection

  • Abnormal findings on laboratory tests, including elevated erythrocyte sedimentation rate, positive C-reactive protein level, and leukocytosis with neutrophil predominance

Sweet syndrome, when limited to the skin, is a benign condition that usually resolves in 5-12 weeks; however, it recurs in almost 30% of patients and can recur more commonly in patients with hematologic cancer.[1] The patient in this case had previously developed similar lesions that responded well to prednisone. This instance was a recurrence. When the associated lesions resolve, they do not leave scars.


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