Children with a petechial rash commonly present to emergency departments. The rash can be associated with serious illnesses, such as invasive meningococcal disease (IMD), but is usually associated with less severe conditions. This article discusses the common and important causes of petechial rash, including IMD, viral illnesses, trauma, Henoch-Schönlein purpura and idiopathic thrombocytopenic purpura. It also analyses the National Institute for Health and Care Excellence (NICE) (2014) pathway for management of petechial rash in children and examines treatment of the various causes. The article includes two relevant case studies and discusses the role of emergency nurses.