Upper Respiratory Tract Infection Leading to a New Diagnosis of Sweet Syndrome and Monoclonal Gammopathy of Unknown Significance.

Background: We present a rare case of Sweet syndrome with underlying monoclonal gammopathy of unknown significance (MGUS) which initially presented as upper respiratory tract infection. Case Presentation: A 52-year-old woman presented with a complaint of sore throat for 6 days, productive cough and fever for 5 days, and red, pruritic, circular, tender rashes on face, arms and trunk for 2 days. There was a past history of similar self-limiting rashes presenting intermittently for 1.5 years. She also reported to be taking tablet ibuprofen, as required for the past 1-2 years, for cervical spondylosis. On integumentary examination, widespread, red, tender, annular plaques (2.5-5 cm in diameter) were noted over the face, back, and arms, with old, healed lesions having hyper-pigmented margins. A blood test revealed leukocytosis (13.6 x 10 Conclusion: It is crucial to investigate Sweet syndrome patients for malignant and premalignant conditions due to their common association. In this case, the patient was diagnosed with MGUS, a clinical condition with 1% risk of conversion into lymphoma or myeloma.