A Challenging Case of Recurrent Fever.

Syndrome of undifferentiated recurrent fever (SURF) includes heterogeneous episodes of systemic inflammation without documented infection, without response to antibiotherapy, and characterized by a paucity of specific clinical or molecular criteria. Colchicine is an effective treatment with an impact on morbimortality. We describe a case of a previously healthy one-year-old male, with consanguineous ancestry, admitted four times due to recurrent fever, associated with nonspecific symptoms and an increase of inflammatory markers in a sepsis-like pattern. No consistent infection was documented, and there was no response to broad-spectrum antibiotics. The evolution revealed corticosteroid dependency. The autoinflammatory syndrome-targeted next-generation sequencing (NGS) gene panel didn't detect relevant pathogenic variants. SURF was postulated as a diagnosis of exclusion, and the effectiveness of colchicine supports an autoinflammatory etiology. We aimed to draw attention to recurrent fevers associated with autoinflammatory disorders due to their challenging diagnosis. Improved understanding of immune pathways and advances in genetic testing will enable greater accuracy in the approach.