VIRAL INFECTIONS

viral skin infections

Many viral skin infections ranging from common to the rare, from the mild to the severe & from those causing just skin infection to those with associated systemic disease. Common viral infection occurs in infants & children.

A virus is a small infectious agent that can replicate only inside the living cells of organisms. Most viruses are too small to be seen directly with a light microscope. Viruses infect all types of organisms, from animals and plants to bacteria and archaea. Since the initial discovery of tobacco mosaic virus by Martinus Beijerinck in 1898, about 5,000 viruses have been described in detail, although there are millions of different types. Viruses are found in almost every ecosystem on Earth and are the most abundant type of biological entity. The study of viruses is known as virology, a sub-specialty of microbiology.

Virus particles (known as virions) consist of two or three parts: the genetic material made from either DNA or RNA, long molecules that carry genetic information; a protein coat that protects these genes; and in some cases an envelope of lipids that surrounds the protein coat when they are outside a cell. The shapes of viruses range from simple helical and icosahedral forms to more complex structures. The average virus is about one one-hundredth the size of the average bacterium.

The origins of viruses in the evolutionary history of life are unclear: some may have evolved from plasmids — pieces of DNA that can move between cells — while others may have evolved from bacteria. In evolution, viruses are an important means of horizontal gene transfer, which increases genetic diversity.

Viruses spread in many ways; plant viruses are often transmitted from plant to plant by insects that feed on sap, such as aphids, while animal viruses can be carried by blood-sucking insects. These disease-bearing organisms are known as vectors. Influenza viruses are spread by coughing and sneezing. The norovirus and rotavirus, common causes of viral gastroenteritis, are transmitted by the faecal-oral route and are passed from person to person by contact, entering the body in food or water. HIV is one of several viruses transmitted through sexual contact and by exposure to infected blood. Viruses can infect only a limited range of host cells called the "host range". This can be narrow or, as when a virus is capable of infecting many species, broad.

Viral infections in animals provoke an immune response that usually eliminates the infecting virus. Immune responses can also be produced by vaccines, which confer an artificially acquired immunity to the specific viral infection. However, some viruses including those causing AIDS and viral hepatitis evade these immune responses and result in chronic infections. Antibiotics have no effect on viruses, but several antiviral drugs have been developed. Viral infections can cause a variety of rashes. Find out more about the skin conditions caused by viruses.

Chicken Pox

Chicken pox is a common infection caused by the varicella virus. This gallery shows pictures of chicken pox lesions in various stages and on different types of skin.

Measles

Measles is a very contagious viral infection that starts out with symptoms similar to influenza. In the United States the incidence has decreased by 99% since a vaccine was developed, but outbreaks do still occur. Learn more about what the rash looks like and how it's treated.

Shingles

Shingles is a painful rash caused by reactivation of the chicken pox virus - varicella zoster. Learn more about how shingles is contracted and what the rash looks like.

Molluscum Contagiosum

Molluscum contagiosum is a viral skin infection that can be confused with warts. Find out more about this self-limited rash that generally affects children.

Fifth Disease

Erythema infectiosum or slapped cheeks disease is a common childhood viral infection that causes red cheeks and a pink lacelike rash on a child's arms.

Viral Hemorrhagic Fever

Viral hemorrhagic fever refers to a group of illnesses caused by a distinct family of viruses. Examples of well-known VHF’s are Ebola Virus, Marburg Virus, Hanta Virus, and Dengue Fever. Find out more about this deadly group of diseases. Hand Foot and Mouth Disease This infection is highly contagious with lesions found primarily on the palms, soles, and in the mouth.

Pityriasis Rosea

Pityriasis rosea is a common, self-limited rash that can be very itchy. Find out more about the appearance and treatment of pityriasis rosea.

Roseola

Roseola is a common viral infection of early childhood and commonly causes a high fever which is followed by a rash once the fever breaks.

Roseola Infantum

Find out more about this very common viral infection that occurs in children.

Rubella

Rubella, or German measles, is a viral infection that most often occurs in the late winter and spring, but since a vaccine was developed in 1969, rubella infections have decreased dramatically. If a pregnant woman contracts a rubella infection, there is a chance it could cause birth defects in her baby. Find out more about what rubella looks like and how it's treated.

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