Milker’s nodule

A 46-year-old male dairy farmer presented with multiple, painful swellings on the right hand and forearm of 10 days duration. He gave a history suggestive of crusted erosions on the udder of one of the cows and the lips of the calf, a few days before the onset of symptoms in himself. The patient did not give any history of comorbidities or recent drug intake or trauma.

He was afebrile and showed multiple, purplish nodules (1.5 × 1.5-3 × 3 cm) with erythematous borders on the dorsal aspect of the right hand, proximal to the first metacarpophalangeal joint and in the first interdigital space [Figure 1]. He had another nodule on the lateral and volar aspect of the right middle finger with a central yellow discoloration [Figure 2]. Two erythematous plaques with central crusts were seen on the extensor aspect of the right forearm proximal to the wrist joint. The skin lesions were firm, and tender, and showed local rise of temperature. The hand was edematous. The right axillary lymph nodes were tender, firm, mobile, and enlarged (1.5 × 1.5 cm).

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Figure 1:

Milker’s nodule manifesting as purplish nodules with erythematous rim (up arrow) and erythematous plaques with central crusting (left arrow).

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Figure 2:

Milker’s nodule manifesting as a nodule with a central yellow color and a peripheral rim of erythema (black arrow).

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With this history and clinical features, a diagnosis of Milker’s nodule with probable secondary bacterial infection was made. The lesional swab was sent for bacterial culture and sensitivity. The patient received amoxicillin-clavulanic acid combination (625 mg per orally twice a day) for 7 days along with acetaminophen (500 mg thrice a day per orally for 3 days). Follow-up after 7 days showed complete resolution of pain, edema, and lymphadenopathy, and a marked resolution of the skin lesions [Figure 3]. The culture was sterile.

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Figure 3:

Resolving lesions of Milker’s nodule.

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Milker’s nodule, caused by the Paravaccinia virus of the genus Parapoxvirus, affects those who have close contact with bovine cattle (milkers and farmers). Orf, a similar condition that affects those who work in close contact with goats and sheep is caused by another virus of the same genus.

Milker’s nodule is a self-limiting condition; however, secondary bacterial infection, erythema multiforme lesions (7–14 days after the nodules), lymphangitis, and lymphadenitis may occur. Electron microscopy and polymerase chain reaction analysis of lesional specimens can confirm the diagnosis. Isolation of infected cattle is recommended to prevent the spread of infection.