We described herein a patient with chronic atypical neutrophilic dermatosis with lipodystrophy and elevated temperature (CANDLE) syndrome and a novel mutation in PSMB8 gene. This patient had multiple visceral inflammatory involvements, including rare manifestations, such as Sweet syndrome and pericarditis. A 3-year-old male, Caucasian, was born to consanguineous healthy parents. At the age of 11 months, he presented daily fever (temperature >40 °C), irritability, hepatomegaly, splenomegaly; and tender and itching, erythematous papular and edematous plaque lesions. Echocardiogram showed mild pericarditis. Skin biopsy revealed a neutrophil infiltrate without vasculitis suggesting Sweet syndrome. Mutational screening of PSMB8 gene revealed homozygous c.280G>C, p.A94P mutation. He responded partially to high doses of oral glucorticoid and intravenous methylprednisolone. Colchicine, azathioprine, methotrexate, cyclosporine, and intravenous immunoglobulin were not efficacious. At the age of 3 years and 1 month, tocilizumab was administered resulting in remission of daily fever and irritability. However, there was no improvement of the skin tenderness and itching lesions.

Conclusion: A new mutation in a CANDLE syndrome patient was reported with pericarditis and mimicking Sweet syndrome. The disease manifestations were refractory to immunosuppressive agents and partially responsive to tocilizumab therapy.