Orf Clinical Presentation

Updated: Jun 06, 2018
  • Author: Aaron Z Hoover, MD, FAAD; Chief Editor: Dirk M Elston, MD  more...
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Presentation

History

Orf occurs in humans with an occupational or household exposure to the virus via infected animals or fomites. The hands are where 95% of cases occur (see the image below). [25] The lesions may be pruritic and are generally painless. If the lesions are painful, then secondary infection should be suspected. [26] With orf, a low-grade fever may occur but usually subsides within 3-4 days. Systemic symptoms such as lymphadenopathy, erysipelaslike lesions, and erythema multiforme can occur in up to one third of cases. [27] Large, fungating orf lesions or multiple lesions have been reported in patients who are immunosuppressed, burn patients, atopic dermatitis patients, and one patient with scleroderma. [26, 28]

A classic location of orf on the index finger. A classic location of orf on the index finger.
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Physical Examination

Orf appears as a solitary lesion or as a few lesions on the fingers, hands, or forearms, and orf has even been reported on the face, scalp, and groin. [29] The orf lesion starts as a small, firm, red-to-blue papule then progresses through a series of 6 stages.  The fully developed orf lesion is typically 2-3 cm in diameter, but it may reach 5 cm.

After incubation of 3-7 days, the orf infection goes through six clinical stages, each lasting about 1 week, as follows:

  • Stage 1 (maculopapular) - A red elevated lesion (see the image below)

    An early lesion of orf (papular stage). An early lesion of orf (papular stage).
  • Stage 2 (targetoid) - A bulla with an irislike configuration (nodule with a red center, a white middle ring, and a red periphery) as shown below

    The target phase associated with edema. The target phase associated with edema.
  • Stage 3 (acute) - A weeping nodule

  • Stage 4 (regenerative) - A firm nodule covered by a thin crust through which black dots are seen (see example below)

    The regenerative stage of orf with a central crust The regenerative stage of orf with a central crust.
  • Stage 5 (papillomatous) - Small papillomas appearing over the surface

  • Stage 6 (regressive) - A thick dry crust covering the resolving lesion

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Complications

Orf infections can be associated with fever, lymphangitis, lymphadenopathy, erythema multiforme, [30, 31] and secondary bacterial infections. Papulovesicular eruptions and bullous pemphigoid‒like eruptions are very rare complications of orf. [32, 33, 34] Blindness has been reported when the diseases affects the eye. [35] Immunocompromised patients can develop giant orf, multiple lesions, and recurrent lesions; these can take longer or may fail to spontaneous resolve. [36] A swan-neck deformity of the index finger has also been reported. [23] Pregnancy and fetal development have not been reported to be adversely affected by this viral infection. [37]

Orf lesion (arrow) associated with erythema multif Orf lesion (arrow) associated with erythema multiforme.
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Dermoscopy

Depending on the stage of the lesion, dermoscopic examination can demonstrate various findings to include a well-defined nodule with a central crust, white structureless areas, a blue-gray area, orange-yellow streaks, white shiny streaks, dotted vessels, hairpin vessels, an erythematous ring, a yellow-white ring, and a fine peripheral scale. [38, 39]

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