Alison Laurie-Chalmers, Senior Consultant, Crown Vets Inverness.
Eosinophilic plaques, granulomas, and indolent ulcers are lesion types that make up the entity of: Feline Eosinophilic Granuloma complex. Eosinophilic plaques, granulomas, and indolent ulcers are specific lesion types that make up the entity of Feline Eosinophilic Granuloma complex. This group of inflammatory lesions is common in cats and they are usually associated with an underlying hypersensitivity, either to fleas (flea allergy), or certain food components (food allergies), or environmental allergens (atopic dermatitis).
The Eosinophilic skin plaques appear as one or few red, raised, eroded skin lesions. The area is usually very itchy and the cat is often observed licking and over grooming the area excessively. Skin plaques may occur anywhere on the body, but are usually found on the skin on the lower abdomen, chest, under the limbs and tail.
Eosinophilic granulomas appear as coalescing raised swollen, firm, linear skin plaques that may be nodular, red, and eroded. Granulomas are not typically itchy. They occur anywhere on the body, but are most often found on the inner thigh (linear granuloma), chin or lips. Granulomas can also occur inside the mouth on the tongue or on the hard palate.
Eosinophilic ulcers (indolent ulcers) appear as small ulcers with raised outer edges on the lips. These ulcers may enlarge and swell and so distort the lip tissues. They are generally not itchy but do cause a visible lip swelling.
To diagnose this problem your Vet will consider the history and findings on a physical examination. Further diagnostics that may be recommended by your Vet are: Cytology to look for the characteristic cells called Eosinophils and also any evidence of secondary infection; Skin scrapings and hair plucks to look for any evidence of ectoparasites or ringworm, and possibly also Skin Biopsies to confirm the diagnosis and to rule out other causes of similar type skin lesions like some skin tumours.
Secondary bacterial infections that are identified are treated with appropriate systemic antibiotics. Treating secondary infections may often decrease the severity of the lesions by 50% or more. Modified Cyclosporine, or systemic glucocorticoids are additional anti-inflammatory medications often used to get these lesions into remission. Antihistamines and oral essential fatty acids may also be prescribed.
Glucocorticoids are often used initially after any secondary infection is resolved and to bring the lesions under control. Cyclosporine or antihistamines also may be prescribed to decrease the likelihood of recurrence whilst the possible underlying allergic cause of the lesions is still pursued. Underlying hypersensitivities and allergies should always be considered as an underlying cause here. These can hopefully be identified and managed and so the symptoms controlled.
Often along with the advised treatments for the active lesion, a strict flea control program for all pets in the home and household treatment to control for fleas is always advised. Also advised would be a strict food trial using a recommended hypoallergenic diet only. If flea allergy and food allergy are then ruled out as the underlying cause, then feline atopic dermatitis due to environmental allergens should be considered as the primary allergy causing the presenting granulomatous lesions.
Sometimes though, frustratingly, the underlying cause of eosinophilic granuloma complex is never determined and is termed idiopathic of no known cause.
The prognosis for eosinophilic granuloma complex is variable, depending on the underlying cause. If an underlying hypersensitivity is identified and controlled, successful treatment and control is more likely. If though an underlying cause is not determined, cats will require life-long anti-inflammatory treatment to control this chronic skin disease, which will require regular check-ups and monitoring by your Vet.