Exanthemata

Abstract

An exanthem (or exanthema) is a widespread skin rash accompanying a disease or fever. It usually occurs in children as part of a common systemic childhood viral infection, but can also occur in adults and can be caused by bacterial infections, toxin or drug reactions. An enanthem (or enanthema) is a rash that occurs in the mucous membrane, typically in the mouth, as the result of the same disease process of an exanthema. Because the presence of a rash is a very striking feature, historically, several of the commonly seen febrile illnesses associated with rash have been recognized and named in numerical order. There are various things to look out for when assessing a patient with exanthema. These can include the type and evolution of the rash, as well as contact, vaccine, drug, sexual, and travel history. ● Type of rash: ■ maculopapular; ■ vesicular; ■ petechial. ● Evolution of the rash: ■ prodrome, if any; ■ date of onset of fever; ■ date of onset of the rash; ■ progression of the rash (e.g. starting location and spread); ■ other associated features (e.g. conjunctivitis, lymphadenopathy, hepatosplenomegaly). ● Contact history: ■ history of contact with anyone with febrile or rash illness; ■ recent local outbreaks, if any; ■ contact with other vulnerable individuals before and after onset of illness (for infection control purposes). ● Vaccine history: ■ recent history of any vaccination; ■ previous vaccination history (particularly MMR and varicella); ■ timing of these vaccines and number of doses. ● Drug history: ■ including antibiotics given for the illness. ● Sexual history: ■ always consider this in any patient. ● Recent travel history: ■ record timing and location; ■ history of insect bites. A good description of the rash can help in narrowing down the possible causes. The commonly seen rashes can be maculopapular, vesicular, or petechial. Maculopapular rash can be further categorized into subtypes. These include: ● morbilliform—a red rash which is measles-like, two to ten mm in diameter, and which merge to form confluent patches.