Download Case of the Month - Ross Bond

Facial alopecia,
scaling and erosions
in a Jack Russell terrier
Author: Ross Bond
Editor: David Lloyd
© European Society of Veterinary Dermatology
History - 1
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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
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History | Signs | Differentials | Tests | Therapy | Notes
History - 2
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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 | Signs | Differentials | Tests | Therapy | Notes
Clinical signs - 1
• Alopecia, scaling, erosions
• Nasal planum unaffected
• Severe skin disease;
lesion well-demarcated
• Smooth-silvery skin at
healing areas rostrally
History | Signs | Differentials | Tests | Therapy | Notes
How would you
approach this case?
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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
History | Signs | Differentials | Tests | Therapy | Notes
Tests - 1
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Principle differential diagnoses
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Dermatophytosis
Demodecosis
Deep pyoderma
Pemphigus foliaceus
History | Signs | Differentials | Tests | Therapy | Notes
Tests - 2
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Diagnostic tests
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Skin scrapings
Wood’s light examination
Fungal and bacterial cultures
(Skin biopsy)
History | Signs | Differentials | Tests | Therapy | Notes
Results - 1
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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
History | Signs | Differentials | Tests | Therapy | Notes
Results - 2
Fungal culture: Sabouraud’s dextrose agar, 5 days
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White colonies with granular
texture
Dark tan / brown reverse
pigment
On microscopy, numerous
microconidia and thin-walled
cigar-shaped macroconidia
Trichophyton mentagrophytes
(granular form)
History | Signs | Differentials | Tests | Therapy | Notes
What is your
diagnosis?
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Do the investigations permit a definitive diagnosis?
Are there any additional investigations which you
think may need to be done?
History | Signs | Differentials | Tests | Therapy | Notes
Diagnosis
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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
History | Signs | Differentials | Tests | Therapy | Notes
How would you deal
with this case?
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What is your prognosis?
How will you advise the owner?
What treatment would you consider?
History | Signs | Differentials | Tests | Therapy | Notes
Prognosis
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Prognosis is good
• However, lengthy antifungal therapy is often
needed with Trichophyton infections in dogs
History | Signs | Differentials | Tests | Therapy | Notes
Therapy
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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
History | Signs | Differentials | Tests | Therapy | Notes
Comment -1
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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
History | Signs | Differentials | Tests | Therapy | Notes
Comment -2
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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
History | Signs | Differentials | Tests | Therapy | Notes
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History | Signs | Differentials | Tests | Therapy | Notes