Febrile exanthema (FE) is an extremely polymorphous clinical entity, frequently seen in daily clinical practice. FE is characterized by diffuse rash and fever. FE is classified in 4 types, depending on the primary skin lesion: macular, maculopapular, vesicular, and bullous exanthema. It is of infectious and non-infectious cause. Among the infectious causes the most frequent is the viral one. FE may affect all ages, but especially children and young people. Usually, FE raises important issues of differential diagnosis, because its clinical and etiological complexity. To decide the most appropriate therapeutic and prophylactic measures for FE, it is important to know the clinical criteria and the specific diagnostic methods.