Periodic fever: Recurrences of fever that last from a few days to a few weeks and are separated by symptom-free intervals of varying duration. This pattern of fever can be caused by recurrent infection, malignancy or noninfectious inflammatory disorders.
Periodic fever that lasts for more than two years is rarely due to a malignancy or an infection. Attacks that follow a predictable course with a similar set of symptoms each time usually reflect a noninfectious cause such as, for example, Still's disease (rheumatoid arthritis typically of juvenile onset but sometimes of adult onset), Crohn's disease, and Behçet syndrome.
A family history of periodic fever is suggestive of one of the hereditary periodic fever syndromes such as familial Mediterranean fever (FMF), the hyper-IgD syndrome, and the tumor necrosis factor (TNF) receptor-associated periodic syndrome.