Despite intensive studies on borreliosis (Lyme Borreliosis, LB), the diagnostics of this disease still poses serious problems. Borreliosis has often been compared to syphilis and called "the last great imitator", as it is also a multiorgan disease, developing in stages, and mimicking in its course other diseases. Main clinical symptoms involve the skin, skeletal-muscular system, circulatory system and nervous system. The diagnosis of LB is based on the clinical picture, though it must be confirmed by results of laboratory diagnostic tests. These may easily give false positive and false negative results. we describe a case of a girl, in whom the disease developed in stages, involved many organs and in the clinical picture suggested other diseases, including borreliosis. The tests performed for borreliosis were positive. The diagnosis and differential diagnosis in this patient are discussed further in the study.

Keywords: Lyme borreliosis, Borrelia burgdorferi