Clinical Manifestation, Dermoscopy, and Scanning Electron Microscopy in Two Cases of Contagious Ecthyma (Orf Nodule)

Orf is a highly contagious skin disease commonly seen in goats and sheep that can be transmitted to people who have direct contact with infected animals. Here, we report the clinical manifestation, dermoscopy, and scanning electron microscopy in two women who developed skin lesions on their hands after handling goats with wounds in the udders. Human orf is usually self-limiting and no specific treatment is needed.


Introduction
Contagious ecthyma also called contagious pustular dermatitis or scabby mouth is a zoonotic disease, called orf in humans, which is caused by a double-stranded DNA virus, ORFV, and usually affects sheep and goats [1,2]. Human infection occurs through inoculation of broken or abraded skin from infected animals or contaminated fomites [1,3].
The clinical manifestation, dermoscopy, and scanning electron microscopy in two women, who developed skin lesions on their hands after handling goats with wounds on the udders, are presented herein.

Case Report
A 63-year-old female came for consultation presenting with an erythematous violaceous plaque on the right index finger that had started 7 days previously. On examination a central necrotic area (Figure 1(a)) was observed. Fracture and acute vascular occlusion were excluded. Laboratory tests were unremarkable. A consultation with the dermatology department was then requested.
The patient raised goats on her farm. The animals had some udder lesions, so she needed to daily bottle-feed milk to the kids. She did not wear gloves while performing this task. During the evaluation of the patient, it was observed that the patient's daughter presented with a similar skin lesion on the left thumb, and she reported that she also helped to feed the little goats. Dermatology exam showed an indurated nodule with central umbilication covered by crust and surrounded by a reddish halo (Figure 1(b)). Dermoscopy of the finger nodule showed an erythematous area, central ulceration, yellow crust, brown dots, a white structureless area partially surrounding the lesion, and dotted vessels ( Figure 2). The diagnosis of orf was suspected.
Upon domiciliary visit to the patient's farm, goats with udder lesions (Figure 3(a)) were found. The electron microscope has been used for the diagnosis of orf. In this case, it showed ovoid particles with a crisscross appearance due to viral particles ( Figure 4); polymerase chain reaction was positive for the specific virus (ORFV) (Figure 4). The patient was advised to feed the kids using gloves ( Figure 5) and to commence local wound care for the lesions, because the disease was showing spontaneous regression.

Discussion
Orf is characterized by one or multiple nodules on the hands and fingers, but also on the feet, legs, neck, and face [1][2][3]. The disease passes through different phases. The first phase occurs after a brief incubation period of 3 to 5 days and presents with a small papule. Then, the lesions enlarge  and progress to nodules that ulcerate and form crusts. The disease usually does not require specific treatment, because the lesions show spontaneous regression within 4-8 weeks [1][2][3]. Besides dermatologic features, the patient may experience some systemic symptoms and signs, such as fever and, less commonly, lymphangitis, lymphadenitis, and ocular damage [2,3]. Orf may also trigger erythema multiforme [4]. The diagnosis is based on the history, physical examination, and some complementary investigations, such as dermoscopy, histopathology, PCR detection, and electron microscopy [1,[5][6][7].
Occupational skin diseases are particularly important in dermatology, because they can lead to high morbidity in workers and can also reduce their productivity. Moreover, they also represent a public health risk.
The case of orf nodules in relatives shows the importance of disseminating knowledge about this skin disease, because the patient was sent to the emergency room due to suspected necrosis of the finger, but actually she had a benign and selfresolving disease.
Although no person-to-person spread occurs, people in the same environment may be contaminated by the same source (infected animal). Differential diagnoses include, depending on the phase of the disease, anthrax, atypical mycobacteriosis, cowpox, pseudocowpox (Milker's nodule), pyoderma, herpetic whitlow, tularemia, keratoacanthoma, fish-tank granuloma, and sporotrichosis [1,2,8]. Dermoscopy is a very helpful tool to diagnose orf and Milker's nodule, but it cannot differentiate between them, so further diagnostic tools are required. We used both electron microscopy and PCR detection to confirm the orf virus diagnosis.
We emphasize the importance of using more specific techniques to confirm the diagnosis, especially when dealing with an occupational skin disease which has repercussions on public system.

Disclosure
All authors meet the criteria for authorship, including acceptance of responsibility for its scientific content. All authors have contributed to prepare and they approved the final manuscript.

Conflicts of Interest
The authors declare no conflicts of interest regarding this manuscript or the work described herein.