Felis ISSN 2398-2950
Skin: dermatophytosis
Synonym(s): Ringworm
Contributor(s): Rosanna Marsella, Ian Mason, David Scarff, David Godfrey
Introduction
- Cause: infection with Microsporum canis most common Microsporum canis .
- Direct and indirect transmission.
- Common zoonosis
.
- Often self-limiting.
- Signs: variable.
- Treatment: responds to treatment with antifungal agents Therapeutics: non-bacterial infection.
Print off the owner factsheet on Ringworm Ringworm to give to your client.
Pathogenesis
Etiology
- Microsporum canis is the most common cause Microsporum canis .
- Trichophyton mentagrophytes Trichophyton spp.
- Microsporum gypseum Microsporum gypseum.
- Other dermatophytes are rare in the cat.
- M. canis: source is usually infected cat.
- T. mentagrophytes: source is rodents or their environment.
- M. gypseum: inhabits rich soil; exposure occurs during digging in contaminated areas.
Predisposing factors
General
- Immunosuppression.
- Breed: Persian, other long-haired breeds.
Pathophysiology
- Transmitted by contact with infected hair and scale, fungal elements in environment or on fomites.
- Mechanical disruption of stratum corneum facilitates infection.
- Fungal hyphae invade hair shaft and migrate downwards; they require actively growing hair to survive.
- Host immune response determines clinical signs; often self-limiting in healthy cats. However, chronic infections are common in long-haired cats.
- Arthrospores germinate within 6 hours of adherence to keratinocytes.
- Skin microtrauma is necessary for infection.
- Grooming eliminates arthrospores from skin.
- Fungal growth in hair → keratinolytic enzymes → penetration of cuticle and hair shaft.
- At keratogenous zone, fungus either reaches equilibrium with keratin production or is expelled.
- When hair enters telogen phase or inflammatory response mounted → spontaneous resolution.
- Toxins produced in stratum corneum → cutaneous inflammation.
- Deeper penetration of keratin surface of epidermis → furunculosis → scarring.
- Dermatophytic pseudomycetoma in Persian cats - sub-cutaneous nodules.
Epidemiology
- Arthrospores of Microsporum canis remain infective for 18-24 months.
- Infection may occur from direct contact with infected cats or via fomites.
Diagnosis
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Treatment
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Prevention
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Outcomes
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Further Reading
Publications
Refereed papers
- Recent references from PubMed and VetMedResource.
- Jacobson LS, McIntyre L, Mykusz J (2017) Comparison of real-time PCR with fungal culture for the diagnosis of Microsporum canis dermatophytosis in shelter cats: a field study. J Feline Med Surg 20 (2), 103-7 PubMed.
- Jacobson LS, McIntyre L, Mykusz J (2017) Assessment of real-time PCR cycle threshold values in Microsporum canis culture-positive and culture-negative cats in an animal shelter: a field study. J Feline Med Surg 20 (2), 108-118 PubMed.
- Moriello K A, Coyner K, Paterson S, Mignon B (2017) Diagnosis and treatment of dermatophytosis in dogs and cats: Clinical Consensus Guidelines of the World Association for Veterinary Dermatology. Vet Dermatol 28 (3), 266-e68 PubMed.
- Moriello K A, Leutenegger C M (2017) Use of a commercial qPCR assay in 52 high risk shelter cats for disease identification of dermatophytosis and mycological cure. Vet Dermatol 29 (1), 66-e26 PubMed.
- Frymus T, Gruffydd-Jones T, Pennisi M G et al (2013) Dermatophytosis in Cats: ABCD guidelines on prevention and management. J Feline Med Surg 15 (7), 598-604 PubMed.
- Garg J, Tilak R, Garg A et al (2009) Rapid detection of dermatophytes from skin and hair. BMC Res Notes 2, 60 PubMed.
- Patel A, Lloyd D H & Lamport A I (2005) Survey of dermatophytes on clinically normal cats in the southeast of England. JSAP 46 (9), 436-439 PubMed.
- Moriello K A (2004) Treatment of dermatophytosis in dogs and cats: review of published studies. Vet Dermatol 15 (2), 99-107 PubMed.
- Sparkes A H, Robinson A, MacKay A D, Shaw S E (2000) A study of the efficacy of topical and systemic therapy for the treatment of feline Microsporum canis infection. J Feline Med Surg 2 (3), 135-142 PubMed.
- Mancianti F, Pedonese F, Millanta F et al (1999) Efficacy of oral terbinafine in feline dermatophytosis due to Microsporum canis. J Feline Med Surg 1 (1), 37-41 PubMed.
- Paterson S (1999) Miconazole/chlorhexidine shampoo as an adjunct to systemic therapy in controlling dermatophytosis in cats. JSAP 40 (4), 163-166 PubMed.
- Greisen A (1998) Dermatophytosis - Incidence of subclinical dermatophytosis in cats living in households with human dermatophytosis. JSAP 8 (2), 43-48 VetMedResource.
Other sources of information
- Leutenegger C (2017) Validation of a qPCR Panel to aid in the diagnosis of dermatophytosis. Abstract presented at: European College of Veterinary Internal Medicine; September 14–16, 2017; St. Julian, Malta.
- Miller W H, Griffin C E & Campbell K L (2013) Dermatophytosis. In: Muller & Kirk's Small Animal Dermatology 7th edition, Elsevier, St Louis. pp 231-243.