Facial alopecia, scaling and erosions in a Jack Russell terrier Author: Ross Bond Editor: David Lloyd © European Society of Veterinary Dermatology

History - 1 10 year-old entire male Jack Russell terrier Good general health Progressive facial skin disease of 4 months duration No response to ampicillin and prednisolone Click to reveal the text on this screen Click the forward arrow to jump to the next screen History

History - 2 Dog lives in rural environment Lesion began as focal area of erythema and scaling caudal to nasal planum Progressed caudally over face despite therapy History

Clinical signs - 1 Alopecia, scaling, erosions Nasal planum unaffected Severe skin disease; lesion well-demarcated Smooth-silvery skin at healing areas rostrally Signs

How would you approach this case? What are the next steps you would take? Make a list of your principle differential diagnoses List any samples you would collect List any tests you would perform to assist in making a definitive diagnosis Signs

Tests - 1 Principle differential diagnoses Dermatophytosis Demodecosis Deep pyoderma Pemphigus foliaceus Differentials

Tests - 2 Diagnostic tests Skin scrapings Wood’s light examination Fungal and bacterial cultures (Skin biopsy) Tests

Results - 1 No evidence of parasites & fungal elements on microscopy No fluorescence on Wood’s light examination Fungal growth evident on mycobiotic agar within 7 days of incubation Tests

Results - 2 Fungal culture: Sabouraud’s dextrose agar, 5 days White colonies with granular texture Dark tan / brown reverse pigment On microscopy, numerous microconidia and thin-walled cigar-shaped macroconidia Trichophyton mentagrophytes (granular form) Tests

What is your diagnosis? Do the investigations permit a definitive diagnosis? Are there any additional investigations which you think may need to be done? Tests

Diagnosis Dermatophytosis caused by T. mentagrophytes Historical and clinical features strongly suggestive, supported by culture results Skin biopsies confirmed hair shaft and follicle invasion by fungal elements Tests

How would you deal with this case? What is your prognosis? How will you advise the owner? What treatment would you consider? Tests

Prognosis Prognosis is good However, lengthy antifungal therapy is often needed with Trichophyton infections in dogs Tests

Therapy Griseofulvin orally at 50 mg/kg (divided twice daily) Enilconazole (Imaverol) emulsion applied every 4th day Good clinical response after 8 weeks of therapy, but repeat cultures still positive Cultures negative and complete clinical response after 12 weeks of treatment, which was withdrawn at this time No relapse over a 6 month follow-up period Therapy

Comment -1 Owner’s lesions were present in this case, illustrating the zoonotic potential of canine dermatophytosis Jack Russell terriers are predisposed to sylvatic dermatophytosis in the U.K. The peripherally expanding, well-demarcated lesions on the face were suggestive of dermatophytosis Notes

Comment -2 Lesions of dermatophytosis vary in appearance and severity Severely inflamed Trichophyton lesions on the face are misdiagnosed as pemphigus foliaceus Absence of focal crusted lesions (“footprints” of vesicopustules) and nasal planum involvement made PF much less likely in this case Notes

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