Alternaria spp

From Dog
Alternaria spp viewed under light microscopy

Alternaria spp are an opportunistic fungal infection of dogs with immunocompromised states. They are normally considered a non-dermatophytic fungi that requires underlying dermatopathy to invade the skin[1]. The incidence of these infections is greater in warm and humid climate[2].

Species which are pathogenic include:

  • Alternaria infectoria[3]

Clinically affected dogs usually present with a history of immunocompromised states such as immune-mediated hemolytic anemia.

Generalized dermatopathy is common with this fungus, and dermal ulcerations, paronychia and fever are common.

A hypersensitivity to fungal hyphae appears to predominate as a cause of lesions.

Thick walled fungal hyphae are usually detected in impression smears from skin lesions. Staining with periodic acid-Schiff's stain is usually confirmatory[4].

Treatment with generalized phaeohyphomycosis usually requires parenteral itraconazole.


  1. Jand SK & Gupta MP (1989) Dermatomycosis in dogs. Mycoses 32(2):104-105
  2. Philpot CM & Berry AP (1984) The normal fungal flora of dogs. A preliminary report. Mycopathologia 87(3):155-157
  3. Caretta G et al (1989) Dermatophytes and keratinophilic fungi in cats and dogs. Mycoses 32(12):620-626
  4. Dedola C et al (2010) Cutaneous Alternaria infectoria infection in a dog in association with therapeutic immunosuppression for the management of immune-mediated haemolytic anaemia. Vet Dermatol 21(6):626-634