Fungal Disease - Candidiasis

Synonyms: candidosis, thrush


Candidiasis is an opportunistic cutaneous infection that results from overgrowth of Candida, a dimorphic fungus that is a normal mucosal inhabitant.

Cutaneous overgrowth is usually facilitated by an underlying factor, such as skin damage caused by chronic trauma or moisture, an immunosuppressive disease, or long term use of cytotoxic drugs or broad-spectrum antibiotics.

Candidiasis occurs only rarely in dogs and cats. Mucosal involvement is characterized by eroded or shallowly ulcerated mucocutaneous junctions, or by single to multiple non healing mucosal ulcers covered by grayish white plaques with erythematous margins.

Cutaneous involvement is characterized by non-healing, erythematous, moist, eroded, exudative, and crusty skin or nail bed lesions.

Differential diagnosis

Differentials include other fungal and bacterial infections and neoplasia.

  • » demodicosis,
  • » pyotraumatic dermatitis,
  • » superficial pyoderma,
  • » mucocutaneous pyoderma,
  • » other fungal infections,
  • » autoimmune disorders,
  • » vasculitis,
  • » cutaneous drug reactions and
  • » Cutaneous lymphosarcoma.


Rule out other differentials.

Cytology (impression smear, exudate): suppurative inflammation with numerous budding yeasts and rare pseudo hyphae.

Dermatohistopathology: superficial epidermidis, parakeratolytic hyperkeratosis, and budding yeasts, along with occasional pseudohyphae or true hyphae in keratin.

Fungal culture: Candida spp. Because Candida is a normal mucosal inhabitant, positive fungal culture results should be confirmed histologically.

Treatment and Prognosis

Any underlying cause must be identified and corrected.

For localized cutaneous or mucocutaneous lesions, the affected area should be clipped and cleaned. The patient should be bathed every 2 to 3 days with shampoo that contains 2% ketoconazole, 1% ketoconazole/ 2% chlorhexidine, 2% miconazole, or 2% to 4% chlorhexidine. Shampoos that have two active ingredients provide better efficacy.

A topical antifungal product should be applied until lesions have healed (approximately 1–4 weeks). Effective topical therapies include the following:

  • » 1% to 2% miconazole cream, spray, or lotion q 12–24 hours
  • » 1% clotrimazole cream, lotion, or solution q 6–8 hours
  • » 2% ketoconazole cream q 12 hours

For oral or generalized lesions, systemic antifungal medications should be administered (minimum 4 weeks) and continued at least 1 week beyond complete clinical resolution. Effective therapies include the following:

  • » Ketoconazole 10 mg/kg PO with food q 24 hours
  • » Fluconazole 10 mg/kg PO q 24 hours
  • » Terbinafine 30–40 mg/kg PO q 24 hours
  • » Itraconazole (Sporanox) 5–10 mg/kg PO with food q 24 hours

Prognosis: is good to fair, depending on whether the underlying cause can be corrected. Candidiasis is not contagious to other animals or to humans.

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