Junctional epidermolysis bullosa in a calf

Abstract

Epidermolysis bullosa (EB) is a hereditary mechanobullous skin disease of animals and human beings, characterized by marked skin and mucous membrane fragility, which triggers the formation of blisters and ulcers in response to minor trauma. The lesions occur due to insufficient connections at the dermis-epidermis junction, due to defects at the basement membrane zone. 4,6 In addition to the formation of blisters, there is a loss of nails, claws, or hooves, and detachment of the epithelium of the oral mucosa. 7,8 The different EB types in domestic animals follow human classification, based on the ultrastructural lesion at the skin basement membrane zone. There are 3 types of EB: epidermolysis bullosa simplex (EBS), characterized by cytolysis of basal keratinocytes producing intraepidermal clefts; junctional epidermolysis bullosa (JEB), in which the separation occurs in the lamina lucida; and dystrophic epidermolysis bullosa (DEB) with cleavage within or below the lamina densa.3 Most types of EB are caused by autosomal recessive genes and appear with low frequency. It is estimated that, in human beings, the disease affects 1 in 17,000 live births in the entire world population. 8In animals, the frequency of EB is not estimated, but there are few reports of the disease. The aim of the current study was to report the clinical, histological, and ultrastructural aspects of a case of EB in a 2-month-old calf, examined in April 2010, at the Veterinary Hospital of the Federal University of Campina Grande (HV/UFCG), Paraíba, Brazil. The calf belonged to a herd of 18 animals. It was descendent from a Gir bull and a Gir crossbreed cow. According to the farmer, a male calf (sired by the same bull) with similar lesions died previously on the farm.The calf had exungulation of all hooves, widespread erosions, and crusts on the skin (Fig. 1A, 1B) and ulcers in the oral cavity (Fig. 1C). The epidermis loosened easily when a little pressure was exerted on the intact skin (positive Nikolsky sign 8 ). Due to the severity of clinical signs and unfavorable prognosis, the animal was euthanized and necropsied. Varying degrees of alopecia, erosions, and crusts were observed on the skin of the metacarpal and metatarsal regions, elbows, knees, ventral thorax, and abdomen and gluteal region. There were also multifocal ulcers on the gums, hard and soft palates, mucosa of the lips, cheek mucosa, and dorsum of the tongue. The other organs showed no significant lesions.Tissue samples from liver, spleen, kidney, adrenal, lymph nodes, thymus, lung, heart, skeletal muscles, thyroid, central nervous system, esophagus, fore stomachs, abomasum, large and small intestine, oral mucosa, tongue, and skin were fixed in 10% buffered formalin, embedded in paraffin, and stained with hematoxylin and eosin, periodic acid-Schiff, and Gomori trichome. Histologically, there was subepidermal separation (Fig. 2), forming blisters filled occasionally with clear eosinophilic fluid, cellular debris, or neutrophils. Epidermal cells showed degeneration evolving to necro...

Epidermolysis bullosa in animals: a review

“…Histopathological findings in skin (Figure b) and oral mucosa are similar to those observed in EBS with separation in the basal layer. In cattle, areas of a total loss of the oral and lingual epithelium are observed, leading to necrosis, extensive ulceration, infiltration by neutrophils and haemorrhages . Similar changes are observed in the vaginal and anal mucosa in horses …”

“…The same pattern is observed in dogs, cats (Figure ), rats and mice with JEB, although the lesions are somewhat less severe. In all animal species with JEB, oral multifocal ulcers are observed (Figure a) . Enamel hypoplasia is a common finding in humans with JEB; in animals, it has only been sporadically observed in horses and dogs .…”

“…In JEB, the clinical signs are due to defects and changes in the hemidesmosomes, the plasma membrane, the sub‐basal dense plate and the anchoring fibrils. In cattle (Figure ), horses, and sheep affected by Herlitz type of JEB, the skin lesions are more severe than in the other types of EB, are distributed throughout the body with all hooves affected at the same time (Figure a,b), and most animals die in the first week of life. The same pattern is observed in dogs, cats (Figure ), rats and mice with JEB, although the lesions are somewhat less severe.…”

“…Abnormalities in the hemidesmosome–anchoring filament complex can cause extreme fragility in the dermo‐epidermal junction . In cattle, horses and rats, abnormalities in this complex include reduced anchoring filaments, small hemidesmosomes without clear demarcation (Figure c) and an attenuated or absent sub‐basal dense plate. In contrast, dogs affected by JEB, with severe fragility of the skin and mucosa caused by mutations in the LAMA3 gene, do not present abnormalities in hemidesmosomes .…”

A COL7A1 Mutation Causes Dystrophic Epidermolysis Bullosa in Rotes Höhenvieh Cattle

“…Inherited forms of EB are well known in humans and in several domestic animal species. Various forms of EB have been described in sheep [4], [5], cattle [6], [7], [8], [9], horse [10], dog [11], [12], [13] and cat [14]. In only five EB cases in domestic animals the responsible gene mutation is known [5], [7], [10], [12], [13].…”