A 54-year-old woman presented with painful lesions on her upper and lower extremities that developed a few weeks earlier. The rash did not improve after two courses of antibiotics. She had a fever and severe generalized pain. Her medical history was unremarkable.

Physical examination revealed an erythematous rash with vesicles and papules (Figure 1). Her temperature was 101°F (38°C). She was admitted for intravenous antibiotic treatment, pain control, and infectious disease consultation. Initial laboratory results showed anemia, thrombocytopenia, elevated erythrocyte sedimentation rate, and elevated C-reactive protein level.

Question

Discussion

The answer is E: Sweet syndrome. Sweet syndrome, or acute febrile neutrophilic dermatitis, is characterized by painful papules, nodules, or plaques caused by an accumulation of neutrophils in the dermis.¹ Multiple tender, erythematous lesions develop on the skin or mucosa, most commonly on the face, neck, and upper and lower extremities.¹ There are three forms of Sweet syndrome: classic, malignancy associated, and drug induced.^2,3 Diagnosis includes major and minor criteria. Major criteria are the rapid onset of painful erythematous plaques and nodules, and typical histopathology of dense neutrophil infiltration without leukocytoclastic vasculitis.⁴ Minor criteria include fever higher than 100.4°F (38°C), erythrocyte sedimentation rate greater than 20 mm per hour, white blood cell count greater than 8,000 per mm³ (8 × 10⁹ per L), neutrophils greater than 70%, and an elevated C-reactive protein level.⁴

Sweet syndrome is often diagnosed in patients who have a history of upper respiratory tract infection, recent immunization, gastrointestinal infection, hematologic or solid neoplasia, or inflammatory disorder, or in women who are pregnant.^1,4 Sweet syndrome responds to treatment with a corticosteroid or potassium iodide.^1,4 In this patient, a bone marrow biopsy confirmed acute myeloid leukemia. About 20% of Sweet syndrome cases occur in patients with cancer.^2,3 A punch biopsy was consistent with the cutaneous infiltrate of chronic myelogenous leukemia.

Contact dermatitis is a delayed cutaneous reaction to an irritant. It is characterized by vesicles, edema, redness, and pruritus.¹

A drug eruption is a diffuse maculopapular or papulosquamous rash or hives that generally spare the face. Common causative medications are penicillin, carbamazepine (Tegretol), and allopurinol.¹

Erythema multiforme is a cutaneous reaction to antigenic stimuli such as drugs or an infection. It may be idiopathic. It is characterized by target lesions, which are maculopapular with central clearing and a discrete ring of erythema. The lesions are symmetric, involving palms, soles, and the dorsum of hands and feet.¹

Erythema nodosum is an acute inflammatory and immunologic reaction of subcutaneous fat to drugs, infection, or inflammatory diseases. It is characterized by pink or dusty-red, firm nodules with blurred edges, most commonly on pretibial surfaces.¹