Facial cutaneous phaeohyphomycosis associated with Alternaria infectoriae infection

Cutaneous nodular disease in the horse is relatively rare and usually associated with arthropod bites, dermal hyperplasia and inflammatory or neoplastic infiltrates. Equine phaeohyphomycosis, particularly alternariosis, has been previously described in the literature and is usually associated with Alternaria alternata. In this article we report a case of phaeohyphomycosis caused by a member of Alternaria section Infectoriae in a horse. To our knowledge this is the first time that this organism has been identified in equids. Despite A. Infectoriae being commonly isolated in individuals receiving immunosuppressive therapy and/or suffering from Cushing's syndrome, we could not determine a link between pituitary pars intermedia dysfunction and fungal infection in this case. The mare responded well to surgical excision of the cutaneous lesions and made a full recovery.