Published on 19/03/2015 by admin
Filed under Dermatology
Last modified 19/03/2015
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Jane C. Sterling
Evidence Levels: A Double-blind study B Clinical trial ≥ 20 subjects C Clinical trial < 20 subjects D Series ≥ 5 subjects E Anecdotal case reports
Orf (ecthyma contagiosum) is an infection by a parapoxvirus, which causes inflammation and necrosis of the skin at the site of viral entry. It is predominantly an occupational disease because the orf virus is carried by sheep and occasionally goats or deer. It has been reported as a result of animal contact with home husbandry or in association with religious observances. Orf infection usually presents as a single lesion, most commonly on the hands or occasionally the face, but lesions can be multiple or very large in immunosuppressed individuals.
Orf is a self-limiting infection and treatment is usually not necessary. The immune response to the virus usually results in resolution of the disease within 2 to 7 weeks without any specific treatment. There is no available treatment that is specifically antiviral for the orf virus and no human vaccine has been produced. Treatment is usually only indicated if there is secondary bacterial infection or immunosuppression. Erythema multiforme can be triggered by orf infection.
Preventive measures include vaccination of sheep before the lambing period to boost immune response and the wearing of gloves if possible when handling animals with any sign of the disease.
Various treatments have been reported anecdotally. Idoxuridine, surgery, and cryotherapy have been suggested to reduce the time to healing. For immunosuppressed individuals, infection with orf may result in a more persistent or progressive infection or giant orf. In such cases, interventional treatment is warranted. Surgery may be performed to remove the bulk of the infected tissue. Idoxuridine, cidofovir, and cryotherapy have also been reported to improve time to healing or to clear persistent infection. Interferon and more recently topical imiquimod cream have shown some potential benefit.
Electron microscopy of scrapings from lesion
Biopsy
Polymerase chain reaction
Diagnosis is usually clinical, but can be confirmed by the above investigations if required.
Nagington J, Newton A, Horne RW. Virology 1964; 23: 4611–72.
The ultrastructural description of the orf virus.
Treatment of Skin Disease Comprehensive Therapeutic Strategies 4e
