Subcutaneous Sweet Syndrome as an uncommon mucocutaneous manifestation in systemic lupus erythematosus: a case report and literature review.

The Sweet Syndrome (SS) as a mucocutaneous manifestation of systemic lupus erythematosus (SLE) has been rarely reported in the literature. The subcutaneous variant of SS in SLE patients is extremely rare. We present a case of a subcutaneous SS occurring as a manifestation of SLE and we discuss the findings reported in the literature regarding this association. The patient was a 31-year-old woman with a recently diagnosis of SLE. On admission she presented with malaise, fever, and skin lesions consisting with tender and warmth large plaques with a violaceous erythema on the right thigh. Laboratory studies showed leukocytosis, neutrophilia, elevated high-sensitive C-reactive protein, hypocomplementemia and increased levels of anti-dsDNA. Others differential diagnosis were ruled out. The skin biopsy revealed a superficial and deep perivascular and periadnexal infiltrate, with neutrophils surrounding adipocytes, concluding the diagnosis of subcutaneous SS. She had a good response to treatment with prednisone 0.5 mg/kg/day, and dapsone 100 mg/day. A structured literature search was performed in PubMed, Web of Science and Scopus, identifying 17 published cases of SS associated with SLE. SS in SLE tends to occur early in the disease course and typically presents as painful violaceous erythematous plaques, accompanied by constitutional SLE manifestations and elevated anti-dsDNA and anti-Sm levels. SS should be considered as a possible manifestation in SLE patients.