Exanthem
Encyclopedia
An exanthem is a widespread rash
usually occurring in children. Exanthems can be caused by toxin
s or drug
s, microorganism
s, or can result from autoimmune disease
.
It can be contrasted with an enanthem
.
The four viral exanthema have much in common, and are often studied together as a class. They include:
Scarlet fever
, or "second disease", is associated with the bacterium Streptococcus pyogenes
. (Measles and scarlet fever were distinguished in the 17th century.) Fourth disease, a condition whose existence is not widely accepted today, was described in 1900 and is postulated to be related to 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:
Rash
A rash is a change of the skin which affects its color, appearance or texture. A rash may be localized in one part of the body, or affect all the skin. Rashes may cause the skin to change color, itch, become warm, bumpy, chapped, dry, cracked or blistered, swell and may be painful. The causes, and...
usually occurring in children. Exanthems can be caused by toxin
Toxin
A toxin is a poisonous substance produced within living cells or organisms; man-made substances created by artificial processes are thus excluded...
s or drug
Drug
A drug, broadly speaking, is any substance that, when absorbed into the body of a living organism, alters normal bodily function. There is no single, precise definition, as there are different meanings in drug control law, government regulations, medicine, and colloquial usage.In pharmacology, a...
s, microorganism
Microorganism
A microorganism or microbe is a microscopic organism that comprises either a single cell , cell clusters, or no cell at all...
s, or can result from autoimmune disease
Autoimmune disease
Autoimmune diseases arise from an overactive immune response of the body against substances and tissues normally present in the body. In other words, the body actually attacks its own cells. The immune system mistakes some part of the body as a pathogen and attacks it. This may be restricted to...
.
It can be contrasted with an enanthem
Enanthem
Mucous membrane Rash arising from another focus of infection.Enanthem or enanthema are medical terms for a rash on the mucous membranes. These are characteristic of patients with smallpox, measles, and chicken pox....
.
Types
Historically, six "classical" infectious childhood exanthems have been recognized, four of which are viral. Numbers were provided in 1905.The four viral exanthema have much in common, and are often studied together as a class. They include:
| Name | Number | Virus |
|---|---|---|
| measles Measles Measles, also known as rubeola or morbilli, is an infection of the respiratory system caused by a virus, specifically a paramyxovirus of the genus Morbillivirus. Morbilliviruses, like other paramyxoviruses, are enveloped, single-stranded, negative-sense RNA viruses... (rubeola) |
"first disease" | measles virus |
| rubella Rubella Rubella, commonly known as German measles, is a disease caused by the rubella virus. The name "rubella" is derived from the Latin, meaning little red. Rubella is also known as German measles because the disease was first described by German physicians in the mid-eighteenth century. This disease is... , identified in 1881. |
"third disease" | rubella virus Rubella virus Rubella virus is the pathogenic agent of the disease Rubella, and is the cause of congenital rubella syndrome when infection occurs during the first weeks of lunacy.Humans are the only known host of this virus.... |
| erythema infectiosum, identified as a distinct condition in 1896. | "fifth disease" | parvovirus B19 Parvovirus B19 The B19 virus, generally referred to as parvovirus B19 or sometimes erythrovirus B19, was the first known human virus in the family of parvoviruses, genus erythrovirus... |
| roseola infantum | "sixth disease" | HHV-6 and HHV-7 |
Scarlet fever
Scarlet fever
Scarlet fever is a disease caused by exotoxin released by Streptococcus pyogenes. Once a major cause of death, it is now effectively treated with antibiotics...
, or "second disease", is associated with the bacterium Streptococcus pyogenes
Streptococcus pyogenes
Streptococcus pyogenes is a spherical, Gram-positive bacterium that is the cause of group A streptococcal infections. S. pyogenes displays streptococcal group A antigen on its cell wall. S...
. (Measles and scarlet fever were distinguished in the 17th century.) Fourth disease, a condition whose existence is not widely accepted today, was described in 1900 and is postulated to be related to Staphylococcus aureus
Staphylococcus aureus
Staphylococcus aureus is a facultative anaerobic Gram-positive coccal bacterium. It is frequently found as part of the normal skin flora on the skin and nasal passages. It is estimated that 20% of the human population are long-term carriers of S. aureus. S. aureus is the most common species of...
.
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:
- VZV (chickenpox or shingles)
- Mumps
- rhinovirusRhinovirusHuman rhinoviruses are the most common viral infective agents in humans and are the predominant cause of the common cold. Rhinovirus infection proliferates in temperatures between 33–35 °C , and this may be why it occurs primarily in the nose...
(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 illnesses like Rocky Mountain spotted feverRocky Mountain spotted feverRocky Mountain spotted fever is the most lethal and most frequently reported rickettsial illness in the United States. It has been diagnosed throughout the Americas. Some synonyms for Rocky Mountain spotted fever in other countries include “tick typhus,” “Tobia fever” , “São Paulo fever” or “febre...
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.
External links
- Overview at About.comAbout.comAbout.com is an online source for original information and advice. It is written in English, and is aimed primarily at North Americans. It is owned by The New York Times Company....
- Definition at MedTerms
- Differential diagnosis
- Dermatology Quiz Includes photo, diagnosis, and treatment of unilateral laterothoracic exanthem (ULE).