POOR WELFARE DUE TO A RARE FUNGAL SKIN DISEASE

Among diseases caused by fungi (i.e. mycoses) dermatophytosis, cryptococcosis and aspergillosis are commonly reported in horses. Conversely, other mycoses are underestimated, often not suspected or diagnosed. This study presents a rare case of Geotricum spp dermatitis. After surgery and antibiotic treatment, a saddle horse (gelding, 11 year old) showed well-circumscribed areas of non-pruritic alopecia. The owner did not promptly call the veterinarian suspecting an allergic reaction. The horse lost more hair and weight; a veterinarian was consulted and corticosteroids were administered since an allergic reaction was suspected. At a different veterinarian examination (1 month later), the skin lesion had worsened with alopecia affecting the face, neck, circumferentially around the lower limbs and shoulders. Large white loosely adherent scale coated affected skin, with thick keratin-rich crusts adherent to the lower limbs. The horse was lethargic, pyretic (40 °C), heart and respiratory rates were increased, and hair was shedding/easily epilated, back legs were swollen, and yellow exudate could be expressed from a skin erosion on the knee. Examination of the blood revealed mild neutrophilia (leucocyte count 14.5 103/µl). Anti-inflammatory and antibiotics were administered. Hair, skin scraping and skin biopsy were collected. Routine diagnostic procedures for isolation of bacteria and ectoparasites were performed, but the sample was negative. A fungal infection was suspected and hair and skin scraping samples were examined microscopically using May Grunwald Giemsa method and cultured onto Sabouraud dextrose agar with chloramphenicol (0.4 mg/ mL), and cycloheximide (0.5 mg/mL). Identification was performed on the basis of macroscopic and microscopic features. Geotricum candidum was isolated. Impression smears were made from skin biopsy sample and hair samples and examined cytologically, after be fixed in methanol and stained with May Grunwald Giemsa. A clump of Geotrichum candidum was found; hyphae were branching, non-parallel walled, with septae. Stable disinfection and baths with local antifungal solution (Virkon S) were performed daily for three weeks, the diet was supplemented with vitamins C and E, the horse grazed at least 6 hours without a rug daily. At the 3 week follow up, the horse had gained weight, the alopecia was decreased, and clinical parameters were normal. The antifungal treatment was continued twice a week for three months. This study suggests G. candidum may cause skin lesions in horses after long-term use of corticosteroids or antibiotics. To ensure the principle of good health, in cases of dermatitis veterinarians should promptly be consulted, and appropriate diagnostic procedures should be carried out to reach a diagnosis.