There are many viral skin infections. They range from the common to the rare, from the mild to the severe and from those causing just skin infection to those with associated systemic disease.
The following is a brief account of a selection of the important viral skin infections. Many of the diseases mentioned here are covered in greater detail elsewhere and the reader is referred to appropriate links.
Nonspecific viral rash
This is a widespread erythematous rash sometimes seen in viral infections. It is accompanied by the common symptoms of a viral infection, such as fever, headache and malaise. The rash usually develops rapidly. The appearance varies but commonly takes the form of an erythematous blotchy eruption.
Local viral infections
See separate Herpes Viruses article.
See separate Shingles and Shingles Vaccination article.
See separate Molluscum Contagiosum article.
See separate Viral Warts (excluding Verrucae) article.
- Orf is contracted from sheep and goats. It is caused by a parapox virus, which infects mainly young lambs and goats who contract the infection from one another (or possibly from persistence of the virus in the pastures).
- Human lesions are caused by direct inoculation of infected material. It may occur in farmers, butchers, vets, children who bottle-feed lambs and possibly even children who play in pastures where sheep have grazed.
- The incubation period is five or six days.
- Lesions are usually solitary but multiple lesions do occur. The lesions are small, firm, red or reddish-blue. They form a lump that enlarges to form a flat-topped, blood-tinged pustule or blister. The fully developed lesion is usually 2 cm or 3 cm in diameter but may be as large as 5 cm.
Although there appears to be pus under the white skin, incising this will reveal firm, red tissue underneath. The lesion is sometimes irritable during the early stages and is often tender.
- They usually occur on the fingers, hands or forearms but may be on the face. Red lymph lines may occur on the medial side of the elbow up to the axilla.
- There may be a mild fever.
- Allergy to the virus may produce erythema nodosum 10-14 days later.
- The lesion may be covered to prevent spread, although human-to-human transmission is rare.
- It resolves spontaneously in 3-6 weeks.
- A vaccine has been developed to control the infection in sheep.
Viral infections that produce rashes
There are a number of viral infections that may cause a rash - most of them typically in childhood. Examples include:
- German measles (rubella).
- Chickenpox (varicella virus).
- Fifth disease (erythema infectiosum) due to parvovirus.
- Roseola (erythema subitum, due to herpesvirus 6).
- Pityriasis rosea (the cause is unknown but it may be caused by herpesvirus types 6 and 7).
- Echovirus and adenovirus infections often produce a rash.
- Epstein Barr virus of infectious mononucleosis, (may cause rash but, if amoxicillin or ampicillin is given, there is almost invariably a rash).
- Primary HIV infection (often associated with a rash).
Other viral infections with skin involvement
Hand, foot and mouth disease
See separate Hand, Foot and Mouth Disease article.
- This is a response of the skin to viral infection in which there is a papular rash which lasts for several weeks.
- Other names include papulovesicular acrodermatitis of childhood, papular acrodermatitis of childhood and acrodermatitis papulosa infantum.
- Causes of the Crosti-Gianotti syndrome include:
- It affects children aged between 6 and 12 months - females more than males. There may be clusters and a preceding upper respiratory tract infection is not uncommon.
- A profuse eruption of dull red spots develops over three or four days. They appear first on the thighs and buttocks, then on the outer aspects of the arms and finally on the face, often in an asymmetrical pattern.
- The spots are 5-10 mm in diameter and a deep red colour. Later they often look purple, especially on the legs, due to leakage of blood from the capillaries. They may develop fluid-filled blisters.
See separate Kaposi's Sarcoma article.
Viral skin infections and sport
Sport increases the risk of transmission of dermatological infections generally. A number of features may predispose to transmission:
- There may be direct skin-to-skin contact (as in rugby, wrestling on other contact sports).
- Profuse sweating may cause maceration of skin and provide a portal of entry.
- Sharing wet areas predisposes to transfer of infection from feet. These include showers and swimming pools. Bare but dry feet, as in judo, other oriental martial arts and gymnastics, are associated with a lower risk of transmission.
- The name implies association with martial arts. In association with rugby it is called 'scrum pox'.
- Transmission is primarily by direct skin-to-skin contact and abrasions may facilitate a portal of entry. The majority of lesions occur on the head or face, followed by the trunk and extremities.
- A prodromal itching or burning sensation is followed by clustered vesicles on an erythematous base which heal with crusts over about one to two weeks. Less often, headache, malaise, sore throat and fever may be reported.
- Recurrent episodes may follow the initial infection.
- Because of its unusual location, herpes gladiatorum any be confused with impetigo, varicella, staphylococcal furunculosis, or allergic or irritant contact dermatitis.
- Accurate diagnosis requires viral immunofluorescence and cultures should be obtained by gently breaking an intact vesicle and firmly rubbing the swab tip across the base of the erosion.
- Treatment of herpes gladiatorum is with oral aciclovir or similar agents and is most effective if commenced at the first symptoms of an outbreak. Topical aciclovir is probably less effective. Any secondary infection should also be treated.
- The virus can survive for hours to days outside the host if conditions are appropriate. Hence, all contaminated surfaces should be cleaned with antiseptic solution. In the vesicular phase and until the crusts have separated, patients should avoid sports which could involve physical contact.
- Herpes simplex acquired in sport is often associated with constitutional symptoms.
- Prophylactic use of valacyclovir has been shown to be efficacious in lowering the incidence of outbreaks of herpes gladiatorum among adolescents at a 28-day wrestling camp.
Viral skin infections tend to be much more aggressive and virulent if the immune system, especially the T-cell system, is inadequate. The classical example is in HIV and skin disease but unusual and gross viral infections of the skin may occur in any condition in which immunity is impaired.
Further reading and references
Viral skin infections; DermNet NZ
Orf: characteristics and diagnosis; Public Health England
Chuh A, Zawar V, Sciallis GF, et al; Pityriasis Rosea, Gianotti-Crosti Syndrome, Asymmetric Periflexural Exanthem, Papular-Purpuric Gloves and Socks Syndrome, Eruptive Pseudoangiomatosis, and Eruptive Hypomelanosis: Do Their Epidemiological Data Substantiate Infectious Etiologies? Infect Dis Rep. 2016 Mar 218(1):6418. doi: 10.4081/idr.2016.6418. eCollection 2016 Mar 21.
Thompson AJ, Matinpour K, Hardin J, et al; Molluscum gladiatorum. Dermatol Online J. 2014 Jun 1520(6). pii: 13030/qt0nj121n1.
Anderson BJ, McGuire DP, Reed M, et al; Prophylactic Valacyclovir to Prevent Outbreaks of Primary Herpes Gladiatorum at a 28-Day Wrestling Camp: A 10-Year Review. Clin J Sport Med. 2016 Jul26(4):272-8. doi: 10.1097/JSM.0000000000000255.