Non-dermatophyte Dermatoses Mimicking Dermatophytoses in Animals

Dermatophytoses in animals are fungal diseases of the skin caused by dermatophyte fungi of the genus Microsporum or Trichophyton. Because the infection is generally follicular, the most common clinical sign is one or many circular areas of alopecia with variable erythema, scaling and crusting, and the primary differential diagnoses are follicular infections, such as bacterial folliculitis and demodicosis. Although dermatophyte folliculitis or ringworm is the most commonly observed lesion of dermatophytoses in animals, other presentations may be observed according to the host species and the dermatophyte involved: dermatophyte folliculitis or ringworm, scaling and crusting in dermatophytosis due to Microsporum persicolor, nodule in case of kerion or mycetoma, matted hairs, seborrheic dermatosis or miliary dermatitis in cats, generalized exfoliative dermatoses in dogs, cats and horses, superficial non-follicular pustules, papules and macules in the Devon Rex cat, pruritic dermatophytoses in dogs, cats and horses, and onychomycosis in dogs, cats and horses. Since manifestations of dermatophytosis are highly variable, particularly in the cat, dermatophytosis should be considered in case of any annular, papular, nodular or pustular dermatoses, alopecic or not, sometimes pruritic, and nodular dermatoses as well.