Periodic fever is defined as recurrences of fever that last from a few days to a few weeks, separated by symptom-free intervals of variable duration. This pattern of fever can be caused by recurrent infections or neoplastic disorders but also by noninfectious inflammatory disorders. It is important to review the medical history carefully in patients with recurrent febrile attacks. Patients with periodic fever that persists for more than two years rarely have infections of malignant disorders. Attacks with a predictable course and a similar set of symptoms, along with a family history of such attacks, may suggest the presence of a noninfectious form of periodic fever. Although numerous disorders, such as juvenile rheumatoid arthritis, Still’s disease and, Crohn’s disease, can cause periodic fever, this article will focus on hereditary periodic fever syndromes. The authors present two cases of the mevalonic aciduria/hyper IgD syndrome of various severity. For differential diagnostic reasons they also draw attention to other, etiologically diverse types of hereditary fever syndromes, such as familial Mediterranean fever, the tumor necrosis factor (TNF) receptor-associated periodic syndrome, the Muckle-Wells syndrome and the familial cold autoinflammatory syndrome.

        Key words: periodic fever, mevalonic aciduria, hyper IgD syndrome, diagnosis