Faecal Occult Blood Test

Case of the Month (Emma Scurrell July 2011)

Alternaria spp. infection in an immunocompromised dog

 A 2-year-old male Labrador was being treated with immunosuppressive doses of prednisolone and azothioprine for immune-mediated panuveitis when he developed ulcerative cutaneous lesions. The following are H&E (x400) sections from the ulcerated skin which was biopsied and fixed in formalin for histopathology. 



 Fig 1. There is a pyogranulomatous dermatitis associated with numerous septate fungal hyphae with non-parallel walls and periodic constrictions (red arrows). 


Fig 2. The fungal organisms occasionally form globose dilatations producing yeast-like structures (red arrows).

 






Final Diagnosis

Pyogranulomatous dermatitis associated with intralesional fungi

Discussion

Fresh tissue was submitted for fungal culture and revealed a heavy growth of Alternaria spp which was sensitive to itraconazole. Alternaria spp. are ubiquitous molds and primary plant pathogens which can cause opportunistic infections in humans and animals, typically secondary to immunosuppression but also secondary to trauma. Case reports of opportunistic cutaneous fungal infections in dogs are scattered throughout the literature and is something to be aware of; the majority of cases are associated with the use of immunosuppressive drugs used to treat immune-mediated conditions e.g. immune-mediated haemolytic anaemia (IMHA). In this case, the dog recovered well following alleviation of the drug-induced immunosuppression and administration of itraconazole.

Previous Monthly Cases

Hypertensive Retinopathy January 2010
FIP in a cat - uncommon presentation February 2010
Phaeohyphomycosis    March 2010 
Scleral Rupture April 2010
Canine and feline epulides May 2010
Erythema multiforme in a labrador retreiver June 2010
Keloidal fibrosarcoma in a labrador retreiver July 2010
Cutaneous epitheliotropic lymphoma  August 2010 
Benign cutaneous histiocytoma  September 2010 
Iridociliary adenoma October 2010
Proliferative thrombovascular necrosis of the pinnae November 2010
Signet-ring cell carcinoma in the stomach of a dog December 2010
Cutaneous infiltrative lipoma in a labrador January 2011

Tonsillar squamous cell carcinoma February 2011
Canine orbital meningioma March 2011
"Lung-digit" syndrome in a cat April 2011
Hepatic amyloidosis in a cat May 2011
Haemophagocytic histiocytic sarcoma June 2011



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Faecal Occult Blood Test