Year : 2009 | Volume
: 54 | Issue : 5 | Page : 78--79
PK Kaviarasan1, M Yamini1, PVS Prasad1, P Viswanathan2,
1 Department of Dermatology, Venerology and Leprosy, Rajaha Muthiah Medical College and Hospital, Annamalai University, Tamil Nadu, India
2 Department of Pathology, Rajaha Muthiah Medical College and Hospital, Annamalai University, Tamil Nadu, India
Department of Dermatology, Venerology and Leprosy, Rajaha Muthiah Medical College and Hospital, Annamalai University, Tamil Nadu
Milker«SQ»s nodule virus is a parapox virus that is endemic in cattle. The virus can be grown in tissue culture of both bovine and human cell lines. We report a 53-year-old male, milker who presented with multiple painful nodules on both hands for one month. The nodules were tender and showed central umblication and surrounding rim of erythema. Both epitrochlear and axillary lymph nodes were enlarged on both sides and were non-tender. The skin biopsy revealed marked edema in the epidermis with monouclear inflammatory cell infilitration in the upper dermis. The diagnosis was made on clinical basis. As there was no specific treatment the patient was managed only with antibiotics for secondary infection. The lesions partially resolved after two weeks. This case in reported for its occupational importance.
|How to cite this article:|
Kaviarasan P K, Yamini M, Prasad P, Viswanathan P. Milker's nodule.Indian J Dermatol 2009;54:78-79
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Kaviarasan P K, Yamini M, Prasad P, Viswanathan P. Milker's nodule. Indian J Dermatol [serial online] 2009 [cited 2020 Jun 7 ];54:78-79
Available from: http://www.e-ijd.org/text.asp?2009/54/5/78/45466
Milker's nodules are caused by infection with a pox virus that is endemic in cattle. The etiologic agent, paravaccinia virus is a DNA virus that duplicates in the cytoplasm of infected cells.  The virus produces mild infections of the teats of cows, i.e. "ring sores", and ulcers in the mouth of calves. This can produce lesion on the hands of milkers or veterinarians who examine the mouth of animals.  An indirect mode of transmission was suggested by the development of milker's nodules following burn injury in four patients who had not had direct contact with infected animals.  Once infected a person becomes immune to re-infection. The incubation period lasts from 5-14 days after which and papules develop on a digit or an extremity within a week. They develop into reddish-blue tender nodules, the center of which forms a small crust. A zone of erythema usually surrounds the nodule. Minimal symptoms are associated with the lesion and patients may develop lymphangitis.  A history of exposure to cattle limits the differential list and points the way to a correct diagnosis. Histopathological changes are not diagnostic and may vary from edematous keratinocytes, intracytoplamic eosinophilic inclusions and a granulomatous reaction in the upper dermis or mononuclear cell infiltration in the dermis. ,
Currently available serological and immunological tests for human parapox virus infection include virus identification by electron microscopy, cell culture and animal experiments. The diagnosis may be confirmed even after skin lesions have healed, by assays for agglutinating, complement fixing, neutralizing and flocculating antibodies in patient's serum. Immunofluorescence and enzyme assays (ELISA) are the most sensitive methods in current use. The three species of the genus of parapox virus may be differentiated by DNA-hybridization techniques or by surface structure analysis using immunoelectron microscopy. The diseases caused by the three parapox virus species are identical in humans. Hence the clinical entity should be called as 'farmyard pox' regardless of the species of virus isolated. Differential diagnosis from orf is not possible on morphological grounds. History of contact with sheep and goats and the presence of heamorrhagic bulla may sometimes help to differentiate.
A 53-year-old male, milker by occupation presented with painful swellings on both hands of one month duration. There was no history of constitutional symptoms. Cutaneous examination showed multiple nodules with central umblication and a surrounding rim of erythema. The nodules were tender and showed oozing and crusting [Figure 1],[Figure 2] Epitrochlear and axillary lymph nodes were enlarged bilaterally and were non tender. A skin biopsy was performed which showed hyperkeratosis with edema in the dermis and intra epidermal separation. Dermis revealed mononuclear cells composed of lymphocytes and infiltrate with histiocytes [Figure 3]. It also showed several thin walled vessels, some of them are congested. All of them are surrounded by chronic inflammatory cell infiltration. Culture could not be done for want of facilities. Other routine investigations including HIV were non contributory. The patient was treated with only prophylactic antibiotics and anti-inflammatory drugs. A review after two weeks revealed spontaneous regression of the nodules and decrease in tenderness. The lesions resolved with pigmentation.
Milker's nodules (pseudo cowpox) are harmless skin lesions most commonly seen in persons whose occupation regularly brings them into close contact with cattle.  In our patient the history and characteristic lesion were clinically suggestive of the diagnosis. Clinicopathological evaluation of cases of Milker's nodules and human Orf was carried out by Groves et al .  The authors also found endophytic strand-like proliferations and distended and edematous dermal papillae in their cases. In high power epidermal viral cytopathic changes with inclusion bodies, clumping of keratohyalin and cytoplasmic vacoulation that had a distinctive "spongiform" appearance within follicular structures were seen.  We also found evidence of viral damage to epidermis and dermis in our patient. Our patient was immuno competent. Milker's nodules may also rarely occur in immuno compromised patients. One such rare case was reported who developed complications like erythema multiforme and graft versus host disease.  As there was no specific treatment our patient was only treated with a course of prophylactic antibiotics. The lesions healed on their own in four weeks time with residual pigmentation. Awareness of their clinical and histopathologic features is important especially with today's threat of biologic warfare. We have to distinguish them from more worrisome entities such as tularemia and anthrax and hence we report this rare case.
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