Author: Dr Amanda Oakley, Dermatologist, Hamilton, New Zealand, 2002. Updated September 2015.
Exanthem is the medical name given to a widespread rash that is usually accompanied by systemic symptoms such as fever, malaise and headache. It is usually caused by an infectious condition such as a virus, and represents either a reaction to a toxin produced by the organism, damage to the skin by the organism, or an immune response.
Exanthems during childhood are very common and are usually due to specific viral infections:
Viral exanthems also include:
Exanthems caused by bacterial infections include:
Other specific infections that can give rise to exanthems include:
Acute connective tissue diseases can present with an exanthem.
Some exanthems are of unknown cause, for example, Kawasaki disease.
Non-specific exanthems appear as spots or blotches and may or may not be itchy. The rash is usually widespread and may be more extensive on the trunk than the extremities. In most cases, prior to the rash appearing, patients may have symptoms of general unwellness that include:
These signs and symptoms may vary depending on the cause of the exanthem. See individual causes for details. Viral exanthems often occur in small epidemics, so there may be other children effected at the same time.
Many exanthems have distinct patterns of rashes and prodromal (pre-rash) symptoms allowing clinical diagnosis.
Consult local laboratory resources to determine the most suitable tests in case of doubt, particularly in a very sick patient or if the exanthem arises during pregnancy or immune suppression.
Tests may include:
Treatment of specific exanthems will depend on the cause.
Symptomatic treatment may include:
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