Straelensiosis in a dog in Spain

Abstract

We read with interest the case report by Seixas F, Travassos P, Pinto ML et al . Dermatitis in a dog induced by Straelensia cynotis ( Veterinary Dermatology 2006, 17, 81-84), 1 in which they described one dog with a highly pruritic, papular and crusted dermatitis induced by Straelensia cynotis in Portugal. The response to the treatment in that case with systemic ivermectins and oral antibiotic therapy was poor and the dog was euthanized. We are writing to document a similar case of dermatitis without pruritus in one dog with a good prognosis without treatment and long-term follow up. 2 In September 2002, a 4-year-old male wire-haired dachshund (9 kg) presented to Hospital Ars Veterinaria with a 2-week history of erythematous papules. These lesions measured less than 1 mm in diameter and were localized to the frontal, periocular, periauricular, cervical, dorsal and lumbar regions; they did not appear to bother the patient and were nonpruritic. The clinical examination was otherwise normal. The dog lived in the city of Barcelona but had visited a rural area in La Bisbal (north-east of Spain, approximately 40 km from the French border) 14 days before showing the first lesions. The initial treatment included a benzoyl peroxide shampoo once a day (Paxcutol, Virbac Laboratories SA, Carros, France) and amoxycillin/clavulanic acid (Synulox, Pfizer, Alcobendas, Spain) 12 mg kg − 1 twice a day per os for 1 week). After 45 days, the lesions had not improved with the treatment and these had become 2-3-mm-diameter papules (Fig. 1). The lesions were not associated with pruritus or discomfort for the dog. The histopathological examination of lesions from the occipital and dorsal areas showed a basophilic material surrounded by an intensely eosinophilic capsule, consistent with a parasitic structure. The epidermis showed mild hyperplasia with hyperkeratosis and mild inflammatory infiltrate by degenerate neutrophils, some macrophages and eosinophils without mast cells. The diagnosis was parasitic dermatitis caused by S. cynotis (Fig. 2).Our findings are consistent with the description of dermatitis induced by S. cynotis in the south of France by Le Net et al ., 3 although our case did not show discomfort or pruritus, and there were no crusts or suppuration as described by Le Net et al . 3 Our case was otherwise healthy and there was no appetite loss. The hypersensitivity reaction seen in trombiculidiasis is usually not described with S. cynotis , and therefore the lesions are rarely pruritic. 3 Seixas et al . 1 suggested that the pruritus was due to the severe perifollicular infiltration of mast cells, and they did not rule out a secondary bacterial infection. In contrast to Le Net et al . 3 the only case with pruritus was attributed to flea and lice infestation. Figure 1. Papular lesions in the dorsal region.Figure 2. Skin biopsy. Basophilic material with a intensely eosinophilic capsule, consistent with a parasitic structure, surrounded by a marked follicular epithelial hyperplasia. Haematoxylin and eosin.