Aims To quantify the phenomenon; to investigate epidemiological and clinical data; to identify anamnestic risk factors and to outline clinical evolution.

Material and Methods Adolescents admitted to our hospital between January 2004 and December 2006, with negative medical investigations, were selected; their medical charts were retrospectively reviewed: age, sex, admission season, clinical manifestations, diagnostic procedures and anamnestic information were assessed. To obtain information about evolution, the patients’ families were contacted by phone.

Results Forty-six adolescents with MUS were found (8%), predominantly females (F : M 4 : 1); most of the admissions were in winter and spring. The clinical presentation was heterogeneous, with symptoms mostly related to the neurological (54%), musculoskeletal (24%) or gastrointestinal system (17%). The neurological symptoms included headache (26%), syncope (19%), and dizziness (13%). The musculoskeletal complaints included arthralgia (18%) and back pain (6%). The gastrointestinal symptoms included abdominal pain (15%), emesis (2%) and constipation (2%). Weakness, fever, dyspnoea, chest pain and “laryngeal stridor” were other rare complaints. The association of different symptoms was commonly found (22 cases), either related to different systems (10 cases) and to the same one (12 cases). The most significant anamnestic triggers were family, peers and school. The prognosis in almost all our cases was good.

Conclusions Our results underline the epidemiological relevance and clinical heterogeneity of MUS; the influence of family, peers and school on their pathogenesis is confirmed. The prognosis is usually good, if properly managed.