What You Need to Know About Oral Eosinophilic Diseases in Dogs and Cats
There are many appearances to canine and feline oral eosinophilic disease, so know what to look for.
© John Lewis, University of Pennsylvania, 2008
Figure 1: Diffuse eosinophilic palatitis in an Italian greyhound.
Originally published in the July 2015 issue of Veterinary Practice News. Loved this article and want to see more like it? Then subscribe today!
I recently saw a 5-year-old, spayed Cavalier King Charles spaniel named Kaycee. Kaycee was presenting for a dental cleaning and possible extractions. Due to Kaycee’s signalment, I knew I should take a look at her soft palate during her conscious and anesthetized examinations. When I opened Kaycee’s mouth, I could see irregularity to the entire surface of the soft palate, with multiple areas of ulceration. Some of the areas of ulceration had areas of yellow punctate raised plaques. Cavaliers are commonly affected by a condition called eosinophilic stomatitis, which often manifests on the soft palate.1 This inflammatory condition is similar to eosinophilic granulomas in cats, but histologically, the disease in Cavaliers often lacks granuloma formation. Other dog breeds may be affected, including Alaskan malamutes, Siberian huskies, Labradors and Italian greyhounds (Figure 1). Soft palate lesions may also be solitary, circular, raised, yellow/pink lesions (Figure 2). Some dogs are presented with clinical signs of decreased appetite and drooling, but surprisingly, many dogs with significant changes to the soft palate show no overt signs at home.
© John Lewis, University of Pennsylvania, 2009
Figure 2: A single eosinophilic plaque on the soft palate of a Labrador retriever.
In cats, oral manifestations of eosinophilic disease can vary greatly. In addition to the classic “rodent ulcers” that commonly occur along the mucocutaneous junction of the upper lip (Figure 3), cats can show other manifestations of eosinophilic disease of the lips, including a non-ulcerated, swollen rostral lower lip and chin (Figure 4). Palate and tongue lesions are also common, having a characteristic raised pink appearance with punctate yellow areas within the affected sites (Figure 5). Less common manifestations include a smooth ranula-like appearance seen in the sublingual area of cats (Figure 6). Occasionally, eosinophilic stomatitis in cats can mimic lymphocytic-plasmacytic stomatitis, with a diffuse pattern of ulceration and inflammation.
© John Lewis, University of Pennsylvania, 2007
Figure 3: Classic “rodent ulcer” eosinophilic granuloma of the upper lip of a cat.
Diagnosis can sometimes be made with fine-needle aspirate and cytology. However, patients requiring diagnosis of an oral swelling often require sedation or anesthesia due to the challenges of obtaining a fine-needle aspirate in the conscious patient, and concerns for patient movement causing the needle to poke an undesired structure, such as the eye. If sedation or anesthesia is necessary, it may be best to forego cytology in lieu of an incisional biopsy to provide the pathologist with more tissue to make an accurate diagnosis. Histopathology may show infiltration of eosinophils, neutrophils and flame figures, which are aggregates of eosinophilic granules, nuclear debris and collagen.
© John Lewis, NorthStar VETS, 2015
Figure 4: Swollen, non-ulcerated, pink/yellow appearance of eosinophilic granuloma of the lower lip of a cat.
The etiology of eosinophilic oral diseases in dogs and cats may vary, but an allergic component seems to play a role in most cases. Allergies to external parasites, inhaled allergens or food allergens may play a role. Consultation with a veterinary dermatologist is helpful to devise a plan for identifying and removing the offending allergens whenever possible. Often, identification of the offending allergen is not possible.
John Lewis, University of Pennsylvania, 2009
Figure 5: Palate and tongue eosinophilic granulomas in the same cat. The punctate areas of yellow are a classic clinical appearance of eosinophilic granulomas.
© John Lewis, University of Pennsylvania, 2008
Figure 6: A pseudoranula in a cat caused by eosinophilic granuloma. Unlike a ranula, the swelling was firm and not fluctuant. This same cat had swelling of the rostral lower lip. Diagnosis of both sites was made via histopathology of an incisional biopsy, and the lesions resolved with steroid treatment.
In one of the earlier published case series of three Cavalier King Charles spaniels affected by eosinophilic stomatitis, treatment with corticosteroids led to resolution of one case and partial resolution of a second. A third case resolved spontaneously without therapy.1 The potential for spontaneous resolution makes it difficult for clinicians to know which therapies truly work, versus the waxing and waning nature of the disease. Treatment often revolves around removal of offending allergens. Strict external parasite control regimens and/or novel food diet trials for eight to 12 weeks may help.3 Patients showing significant clinical signs from their eosinophilic disease may benefit from oral steroids. Some cases appear to be refractory to steroids and other immunomodulators, result in control of the condition rather than a cure. I have used CO2 surgical laser to remove the proliferative portions of eosinophilic granulomas, such as the one seen in Figure 5. Diode laser has also been described for removal of a tongue granuloma in a cat.2 I have not had experience with use of therapeutic laser for treatment of eosinophilic oral disease, and peer-reviewed literature of its use is currently difficult to find. One practitioner told me her cat’s eosinophilic granuloma resolved after switching from plastic to glass food bowls. A randomized, double-blind prospective study compared treatment of feline eosinophilic plaques with amoxicillin-clavulanate versus placebo. The treated group had a 42 percent decrease in mean lesion size compared to a 37 percent increase in the placebo group.4 My personal experiences with use of amoxicillin-clavulanate or other antibiotics for eosinophilic diseases have not shown marked improvement.
There are many appearances to canine and feline oral eosinophilic disease. Hopefully, this column will serve as a reminder of the diverse appearances that you may encounter in practice!
- Joffe DJ, Allen AL. “Ulcerative eosinophilic stomatitis in three Cavalier King Charles spaniels.” J Am Anim Hosp Assoc. 1995; 31: 34-37.
- Kovács K, Jakab C, Szász AM. “Laser-assisted removal of a feline eosinophilic granuloma from the back of the tongue.” Acta Vet Hung. 2009; 57: 417-426.
- Jergler D. “Causes of feline skin allergies are elusive.” Vet Pract News. 2015; 27: 1.
- Wildermuth BE, Griffin CE, Rosenkrantz WS. “Response of feline eosinophilic plaques and lip ulcers to amoxicillin trihydrate-clavulanate potassium therapy: a randomized, double-blind placebo-controlled prospective study.” Vet Dermatol. 2012; 23(2):110-118.