Milker’s nodule

Milker's nodule is caused by a parapoxvirus mainly contracted from the teats of cows. Lesions, which are most commonly found on the fingers, have a similar appearance to those of Orf, which is contracted from sheep and goats.

This chapter is set out as follows:

• Orf is mainly found on cows teats and the muzzles of calves
• The infection is transmitted by direct inoculation from cows to dairy farmers or vets who examine the mouths of animals
• The incubation period is 5-14 days

Distribution

• Mainly the hands, especially the fingers. Occasionally the face
• Lesions are usually a few in number but can be solitary

Morphology

• Lesions have a similar, but not identical appearance to Orf
• They start as small, red, flat-topped papules
• Within a week lesions develop into red-purple, firm, slightly tender nodules, 0.5-1.5 cm in diameter
• The surface then becomes grey and crusted with a surrounding area of erythema
• There may be secondary bacterial infection

Other features

• Mild lymphangitis, which is rarely associated with significant constitutional upset
• Milker's nodule are occasionally associated with an erythema multiforme-like eruption

• Milker's nodules are self-limiting and resolve spontaneously over 4-6 weeks