An exanthem is a widespread rash occurring on the outside of the body and usually occurring in children. An exanthem can be caused by toxins, drugs, or microorganisms, or can result from autoimmune disease.
|Rash seen in rubella|
The term exanthem is from the Greek ἐξάνθημα, exánthēma, 'a breaking out'. It can be contrasted with an enanthems which occur inside the body, such as on mucous membranes.
The four viral exanthema have much in common, and are often studied together as a class. They are:
|(rubeola) measles||"first disease"||measles virus|
|rubella, ("German measles") identified in 1881.||"third disease"||rubella virus|
|erythema infectiosum, identified as a distinct condition in 1896.||"fifth disease"||parvovirus B19|
|roseola infantum||"sixth disease"||HHV-6 and HHV-7|
Scarlet fever, or "second disease", is associated with the bacterium Streptococcus pyogenes. Fourth disease, a condition whose existence is not widely accepted today, was described in 1900 and is postulated to be related to the bacterium Staphylococcus aureus.
Many other common viruses apart from the ones mentioned above can also produce an exanthem as part of their presentation, though they are not considered part of the classic numbered list:
- Varicella zoster virus (chickenpox or shingles)
- rhinovirus (the common cold)
- unilateral laterothoracic exanthem of childhood
- Some types of viral haemorrhagic fever are also known to produce a systemic rash of this kind during the progression of the disease.
- Tick-borne diseases like Rocky Mountain spotted fever produce a rash that may become extensive enough so as to be classified as exanthemous in as many as 90% of children with the disease.
- "Roseola Glossary of Terms with Definitions on MedicineNet.com". Archived from the original on 2008-09-14.
- Bialecki C, Feder HM, Grant-Kels JM (November 1989). "The six classic childhood exanthems: a review and update". J Am Acad Dermatol. 21 (5 Pt 1): 891–903. doi:10.1016/s0190-9622(89)70275-9. PMID 2681288.
- "fifth disease" at Dorland's Medical Dictionary
- Weisse ME (January 2001). "The fourth disease, 1900-2000". Lancet. 357 (9252): 299–301. doi:10.1016/S0140-6736(00)03623-0. PMID 11214144.
- Altman, Lawrence K (November 30, 1982). "THE DOCTOR'S WORLD". The New York Times. Retrieved 2009-11-07.