SummaryMost childhood exanthemas are harmless. However, recognizing serious diseases with life‐threatening complications at an early stage is important for the timely initiation of adequate therapy. This requires knowledge of the specific patterns of the exanthema, obtained from the medical history and the clinic, including the patient’s general condition and physical examination. In unclear cases, additional diagnostic measures are undertaken, such as blood tests and smears (cutaneous, mucocutaneous).Viruses are the most common cause of childhood exanthemas. New variants of infectious agents, improved diagnostics and stays in tropical and subtropical countries have expanded the spectrum of infectious exanthemas.