From January to March 2011, four related Sumatran tigers (sire and three juvenile littermates) simultaneously developed single to multiple well-demarcated, erythematous and ulcerated plaques on the skin of the back or at the tail base. Skin lesions were diagnosed histologically as eosinophilic plaques, characterized by chronic eosinophilic diffuse to perivascular dermatitis with acanthosis and ulceration. Due to marked ulceration, advanced cases of eosinophilic plaque, such as these, can resemble herpetic dermatitis and insect bite hypersensitivities. Eosinophilic plaque is distinguished (from the other feline eosinophilic skin diseases) by prominent acanthosis, spongiosis, and mucinosis and the absence of eosinophilic degranulation (“flame figures”), granulomatous inflammation, or intranuclear inclusions.1 Two of the four tigers also developed lip lesions consistent with indolent ulcers and one tiger developed an oral plaque suggestive of an eosinophilic granuloma. While eosinophilic plaques are often related to an underlying allergic hypersensitivity, indolent ulcer and eosinophilic granuloma often lack a direct association with clinically evident hypersensitivity. At the same time as the lesions developed, the keepers observed a significant increase in the biting stable fly (Stomoxys calcitrans) population. Therefore, treatment included oral prednisone, intralesional Depo-Medrol, topical hydrocortisone, and fly control (repellant and exhibit foliage removal). Near complete resolution was observed within three months, by late April to early May 2011. Previously published cases of oral eosinophilic granulomas in tigers have been treated with corticosteroids, surgical removal, cryotherapy, and antibiotics with variable resolution.2 The juvenile littermates were exported or are currently being prepared for exportation to other institutes without reports of further recurrence.
The authors thank Dr. Verena Affolter for her expertise.
1. Gross TL, Ihrke PJ, Walder EJ, et al. Skin Diseases of the Dog and Cat: Clinical and Histopathologic Diagnosis. 2nd ed. Oxford, UK: Blackwell Publishing Co.; 2005:121–122,352–353.
2. Sykes JM, Garner MM, Greer LL, et al. Oral eosinophilic granulomas in tigers (Panthera tigris)—a collection of 16 cases. J Zoo Wildl Med. 2007;38:300–308.