Abstract Hereditary periodic fever syndromes (HPFSs) are a group of inherited disorders of the innate immune system caused by mutations of genes involved in the regulation or activation of the inflammatory response, which belong to the category of autoinflammatory disorders. Most HPFs typically have an onset in pediatric age, while a limited number of patients experience disease onset during adulthood. The relative rarity and lack of information on adult-onset autoinflammatory diseases make it likely that genetic testing is often inconclusive. Recently, we have identified a set of variables related to the probability of detecting gene mutations in MEFV , responsible for familial Mediterranean fever, and TNFRSF1A , responsible for tumor necrosis factor receptor-associated periodic syndrome. In addition, we have proposed a diagnostic score for identifying those patients at high risk of carrying mutations in these genes. However, before the score can be recommended for application, further evaluation by means of longitudinal studies on different ethnicities and different populations deriving from other geographical areas is needed in order to definitively verify both its sensitivity and its specificity. The present manuscript offers our suggestions on how to establish a differential diagnosis for adult-onset HPFs, as well as a review of the literature, and we also provide a score revision available online.