[Lyme disease. Is it so uncommon?].

Lyme disease, caused by Borrelia burgdorferi sensu lato, is a multisystem disease that may occur with rheumatic, dermatological, neurological symptoms and heart diseases. Its most typical lesion is erythema migrans, although not always present. The clinical diagnosis is supported by serology, and treatment is almost always tetracycline in young people and adults. Amoxicillin is most often used in children and pregnant women, and cephalosporins in the presence of neurological signs. The prognosis, with the appropriate treatment, is good. But if not treated promptly, there may be chronic signs, particularly, neurological, which may be disabling. In Spain, where the incidence is low, antimicrobial prophylaxis is indicated the after a tick bite.