Milker’s Nodules - Causes, Symptoms, Diagnosis, and Treatments

Introduction

Milker's nodules are occupation-related virus-infected skin conditions, and the paravaccinia virus causes them. The paravaccinia virus is the virus present in dairy cattle. The spread of viral infection happens through the contact or physical touch of the infected cows' udder, nose, meat, and other contaminated objects. The clinical presentation of the milker's nodules is primarily asymptomatic. Rarely observed symptoms of milker’s nodules include fever and lymphadenopathy. The condition associated with milker's nodules is the erythema multiforme. The diagnosis of milker's nodules is based on the history, skin features, and biopsy examination. The milker's nodules are benign and a self-limiting condition.

What Are Milkers Nodules?

Milker's nodules are occupation-related skin conditions caused by the paravaccinia virus. Milker's nodule is also referred to as the pseudocowpox virus. Milker's nodule is typically characterized as the erythematous nodules mainly observed in hands and forearms. Sometimes the clinical features of the milker's nodule are seen on the face. Hyperkeratosis and acanthosis are present in the histopathological findings of milker's nodule, and the diagnostic part of milker's nodule is similar to the skin condition orf. The orf and milker's nodule is caused by the virus belonging to the same genus and family. The virus in the bovine cattle causes milker's nodule, whereas the virus in sheep causes orf. The milker's nodule is the self-limiting condition. The milker's nodule is known by several names, and the terms for the milker's nodule are listed below:

• Milker's node.

• Paravaccinia.

• Pseudocowpox virus.

• Farmyard pox.

What Causes Milkers Nodule?

Paravaccinia virus is the causative agent of the milker's nodule. The paravaccinia virus is the DNA (deoxyribonucleic acid) virus and belongs to the poxvirus. The milker's nodule or pseudocowpox virus belongs to the genus parapoxvirus. Milker's nodules are distributed widely and are common in people working on dairy farms, and the spread of viral infection happens through the touch of the infected teats of cows. The individual managing the cattle is more prone to milker’s nodules and other occupation-related dermal conditions. It is also observed that cattle workers and veterinary doctors are more prone to milker's nodules and other similar types of conditions. Milker's nodule does not appear in human-to-human contact. The exact etiology of the milker's nodule is given below:

• Causative Agent: Paravaccinia virus.

• Family: Pox virus.

• Genus: Parapox virus.

• Spread of Infection: By touching the infected udder, noses, teats of cows, and other contaminated objects.

What Are the Symptoms of Milkers Nodule?

The milker's nodule is the occupational dermatosis characterized as erythematous maculopapular lesions. The patient is asymptomatic, and the early symptoms are fever. The incubation period for paravaccinia virus is five to 15 days, and the lesions spread widely. The symptoms of the milker's nodule are given below:

• Erythematous nodules are tiny red spots that are flat and raised on the hands and arms.

• Reddish blue firm nodules and blisters are present within a week of infection.

• Nodules can be solitary or multiple.

• Fingers are typically affected.

• Gray skin and a slight crust are on top of the nodules.

• Secondary bacterial growth also occurs.

• Lymphangitis includes the red streaks following the lymph channels, mainly on the arms.

• The enlargement of lymph glands is called lymphadenopathy.

• Some patients develop erythema multiforme one or two weeks following the emergence of the milker's nodules. This manifests itself as a rash of little raised patches or blisters on the hands, arms, legs, and neck. This rash will go away in one or two weeks.

What Is the Diagnosis of Milkers Nodules?

The diagnosis of the milker's nodule is based on the history of symptoms, physical examination, and biopsy. The symptoms of milker's nodules are observed in the hands, arms, legs, and neck. The face is rarely involved in the milker's nodule. The skin biopsy is taken from the affected area, and histopathological findings are examined.

1. History of symptoms.

2. Physical examination.

3. Skin biopsy.

4. Histopathological findings of the milker's nodules are given below.

• Squamous crust.

• Formation of cysts.

• Necrosis in the epidermis layer.

• Apoptosis of keratinocytes.

• Balloon-like degeneration, mainly in the upper third cells of the epidermis.

• Inflammatory infiltration in the superficial and dense region of the dermal layer.

• Eosinophils are rich and mononuclear.

• Hyperkeratosis and acanthosis are present.

• Multilocular blisters are present.

5. Tissue culture.

6. Electron microscopy helps in the demonstration of the virus.

7. Polymerase chain reaction, PCR.

8. Serology antibody detection tests.

What Is the Differential Diagnosis of Milkers Nodules?

The signs and symptoms of milker's nodules are similar to other skin conditions, especially orf. Biological warts and bioterrorism are essential for differential diagnosis. Some of the differential diagnoses of milker's nodules are mentioned below:

• Orf.

• Brown spider bite.

• Pyoderma.

• Cutaneous tuberculosis.

• Anthrax.

• Sporotrichosis.

• Atypical mycobacteriosis.

• Cowpox.

What Is the Treatment of Milkers Nodules?

In most cases, medical therapy is unnecessary for the milker's nodule. Most of the symptoms of milker's nodules will be resolved within four to six weeks. In case of secondary bacterial infection, medical therapy is suggested. Protective measures should be followed, such as wearing personal protection equipment; PPE is done to avoid the milker's nodule condition. Wearing personal protection equipment will avoid the spread of the milker's nodule. The other preventive measures to prevent the infection of milker's nodules are given below:

• Good personal hygiene is maintained.

• Wearing gloves while managing cattle is followed.

• Personal protection equipment, a PPE kit, is worn to prevent the spread.

• The lesions are covered to prevent the spread to other people.

• Avoid scratching and bursting the blisters.

Conclusion

Milker's nodules are occupation-related dermal conditions caused by the DNA virus called paravaccinia virus. The milker's nodules are called pseudocowpox, paravaccinia, or farmyard virus. Mostly the milker's nodule is asymptomatic and characterized as the erythematous nodules and blisters associated with fever, lymphadenopathy, and erythema multiforme. The symptoms are most commonly present in the hands and arms. Milker's nodules are a self-limiting condition, and the symptoms are resolved independently. Usually, medical therapy is not indicated, but treatment is advised in case of secondary bacterial infections. Preventive measures like wearing gloves while milking, managing, and vaccinating cattle are followed to avoid spreading the disease. People managing cattle can wear personal protection equipment (PPE) to prevent contamination. However, the prognosis of milker's nodules is good in healthy persons.