Pyrexia as the primary paradox: celiac disease masked as fever of unknown origin.

Celiac disease (CD) can present solely with atypical extra-intestinal symptoms. We describe a 33-year-old woman hospitalized for a one-month history of fever, myalgias, and tachycardia. Extensive infectious, autoimmune, and malignancy investigations were unrevealing. However, hypochromic anemia and elevated CRP prompted serologic testing, revealing positive anti-transglutaminase IgA. Duodenal biopsy confirmed CD with Marsh IIIa villous atrophy. This case illustrates CD as a rare etiology of fever of unknown origin (FUO), emphasizing the importance of celiac serology in the differential diagnosis of prolonged unexplained fever.