A Fever, Then a Papular Eruption: Make a Rash Diagnosis

Nicole P. Huffman, MD


April 06, 2012

Discussion: The Sweet Spot

Given the clinical, histologic, and laboratory findings, the patient was diagnosed with acute febrile neutrophilic dermatosis, also known as Sweet syndrome.

Sweet syndrome was initially described in 1964 by Dr. Robert Sweet.[1] It is an uncommon skin eruption characterized by the sudden onset of fever; leukocytosis; and tender, pink, well-demarcated papules and plaques that classically involve the dorsal hands, forearms, face, and chest.[1,2,3] The papules can be intensely edematous, leading to secondary vesiculation or pustulation. The lesions are rarely pruritic. Adult women are predominantly affected, with an average age at onset of 30-60 years.[1,2]

The exact pathogenesis of Sweet syndrome is unknown, but some believe it to be a hypersensitivity reaction with local or systemic dysregulation of cytokines.[1] The eruption tends to be self-limited, resolving spontaneously within 5-12 weeks.[1,2]The syndrome recurs in up to 30% of patients.[1]

Extracutaneous involvement commonly accompanies skin findings. Fever, the most common systemic finding, is present in up to 80% of patients with Sweet syndrome. Ocular involvement is also frequently seen and includes conjunctivitis, episcleritis, and iridocyclitis. Additional systemic findings in Sweet syndrome include arthralgia or myalgia, neutrophilic pulmonary alveolitis, and acute renal failure. An elevated sedimentation rate and leukocytosis are characteristically seen on laboratory studies.[1,2,3]

Subtypes of Sweet syndrome. Sweet syndrome is commonly divided into 4 distinct subtypes on the basis of pathogenesis:

  • Classic or idiopathic Sweet syndrome;

  • Malignancy-associated Sweet syndrome;

  • Sweet syndrome associated with inflammatory disease; and

  • Pregnancy-related Sweet syndrome.

The classis subtype is by far the most common and represents close to 70% of cases. Classic Sweet syndrome typically follows an upper respiratory tract infection (most commonly with Streptococcus species) or gastrointestinal infection (most commonly with Yersinia species). Other associated infections include toxoplasmosis, tuberculosis, chronic hepatitis, and HIV.[1,2,4,5]

Malignancy-associated Sweet syndrome represents approximately 10% of cases. The skin eruption is commonly seen as the initial presentation of the cancer. Hematologic cancer, usually acute myelogenous leukemia, is often the underlying culprit. Atypical bullous or necrotic Sweet lesions are more typically seen with an associated leukemia. Solid tumors can also be involved and are more likely to be found in the genitourinary tract or breast.[4,6,7]

Inflammatory bowel disease and Behçet syndrome are the more common disorders underlying inflammatory disease-associated Sweet syndrome. Pregnancy-associated Sweet syndrome typically presents early in pregnancy (first or second trimester) and has not been shown to pose a risk to the fetus. Like many other dermatoses of pregnancy, Sweet syndrome can recur with subsequent pregnancies.[1,2]

Treatment for Sweet Syndrome

As mentioned previously, lesions are self-limiting and resolve spontaneously within 12 weeks. Oral corticosteroids, usually at a dosage of 1 mg/kg/day, can clear skin manifestations in a matter of days.[1,2]


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