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Dermatophytosis

Diagnosis13

No one test is considered a gold standard. Dermatophytosis is diagnosed by utilizing a number of complementary tests:
  • Wood’s lamp
  • Diagnosis Mackenzie toothbrush technique
  • Biopsy with special fungal stains for nodular or atypical infections
  • PCR detection of dermatophyte DNA
  • Dead fungal organisms from a successfully treated infection will still be detected on PCR, as will dead organisms from noninfected fomite carriers.
Considerations that can make dermatophytosis rank higher on the differential list12:
  • Indoor/outdoor cat
  • Recently adopted kitten
  • Older immunocompromised cat
  • Persians and other long-haired cats
  • Some cases such as miliary dermatitis and self-induced alopecia

Treatment13

Topical and systemic antifungal therapy should always be combined.

Topical Treatment

  • Decreases the infectious material on the hair coat and minimizes environmental contamination.
  • Twice-weekly application of lime sulfur, enilconazole or a miconazole/chlorhexidine shampoo (Malaseb® product information) is recommended as effective topical therapy.
  • Chlorhexidine as monotherapy is not recommended due to poor efficacy.

Systemic Treatment

  • Itraconazole and terbinafine are the most effective and safe treatments for dermatophytosis.

Monitoring

  • Negative PCR in a treated cat is compatible with cure.
  • Negative fungal culture from a cat with no lesions and a negative Wood’s lamp (except for glowing tips) is compatible with cure.
  • The decision to stop treatment should be based on two consecutive negative fungal cultures, taken 2 weeks apart.

Environmental disinfection

  • Minimizing contamination of the environment involves clipping of affected lesions, topical therapy, and routine cleaning of the environment and objects that are in contact with the affected animal.
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