Purpose of review: Determining the viral cause of a rash presents significant diagnostic challenges. We review contemporary literature on viral exanthems and suggest a structured approach to aid diagnosis.
Recent findings: Strains responsible for, and the clinical presentation of, enteroviral infections have diverged from classic descriptions. The causative relationship between antibiotic administration and rash in Epstein-Barr virus infection has been recently questioned. Major measles virus outbreaks have recently occurred in Europe and the USA. The largest Ebola virus outbreak in West Africa has resulted in importation of the virus to other countries and secondary local transmission. Autochthonous transmission of Chikungunya virus has occurred in nonendemic areas, including Europe, the Caribbean and Americas. Zika virus has re-emerged in the Pacific with local transmission from imported cases. Climate change, global warming and spillover of zoonotic viruses are contributing to the emergence and spread of viral diseases.
Summary: Important clues to the diagnosis of viral exanthems include their distribution and morphology, geographic location and potential exposure to vector-borne or blood-borne viruses. Diagnosis is commonly made via serology, nucleic acid tests or, rarely, viral culture. Skin biopsy is not usually required. In general, viral exanthems are self-limiting and treatment is supportive.