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The term Eosinophilic Granuloma Complex (EGC) refers to a group of inflammatory skin conditions in cats. There are a number of different forms of this condition recognised and it appears that these are all reactive patterns initiated by a number of underlying causes. Most forms represent some form of underlying allergy disorder. The lesions are often very itchy and can be worsened by the cat excessively licking at them.

Different forms of EGC

Eosinophilic ulcer, indolent ulcer, rodent ulcer

These lesions occur on the edge of the upper lip of the cat on one or both sides, usually towards the front of the lip, and sometimes also inside the mouth on the hard palate. The lip develops a clearly demarcated ulcer that can have a raised border and there may be marked swelling of the lip in the region of the ulcerated area. Some cases can develop very large and extensive areas of ulceration. There may be enlargement of regional lymph nodes.

Eosinophilic plaque

These can be single or multiple lesions and can be found anywhere on the body with the most common sites including the belly (ventrum) and the inside of the thighs. The lesions are often very itchy with loss of overlying hair. Many plaques have an ulcerated surface and appear quite red and inflamed. They are uncommonly associated with lymph node enlargement.

Eosinophilic granuloma

These lesions can also occur anywhere on the body with the most common locations being the hind legs, foots pads and on the tongue and hard palate. These lesions can appear quite variable but usually consist of a raised area of thickened skin that is often reddened. There may be hair loss and ulceration over the lesion and they are sometimes itchy.

Causes

• Hypersensitivity disorders/allergies: flea allergy dermatitis, food allergy, atopy
• Reactions to ectoparasites (fleas, mites)
• Bacterial infections
• Foreign body reactions
• Irritant reactions
• Self-trauma
• Endoparasites
• Genetic predisposition

Diagnosis and Investigation

Suspected cases of EGC require a full dermatological work up to rule out all other possible causes. Your vet will recommend specific test for your cat which will depend on an evaluation of a full history and physical examination.

Tests may include:

• Coat brushing with a flea comb for fleas
• Superficial and deep skin scrapings
• Skin surface cytology
• Wood Lamp examination
• Fungal culture for dermatophytes 
• Treatment trial for fleas – often cats with flea allergies will not have a high burden of fleas due to over-grooming
• Food elimination diet for a minimum of 8 to 12 weeks
• Blood work such as a complete blood count, serum biochemistry and retroviral testing
• Skin biopsy – this is an essential step to rule out other serious diagnoses such as skin cancer, viral infections, autoimmune diseases
• Intradermal skin testing or Heska Allercept blood testing
• Specialist dermatologist referral

All of the above can be performed at our Hospital including specialist referral.

Treatment

If possible, the underlying allergy should be identified and addressed as the lesions will not resolve unless this is successful. All cases should undergo a comprehensive flea control program in addition to an elimination diet trial. Secondary fungal and bacterial infections also need to be treated with appropriate medications.

Symptomatic treatment of lesions is often necessary while investigations for an underlying cause is carried out and will be ongoing if an underlying cause is not identified. Glucocorticoids are the most common first line of symptomatic treatment and many cases will respond very well to these. The duration and dose will vary from case to case and some may require continuous or pulse treatments to control the disease. Supplementation of essential fatty acids in the form of fish oil may benefit some cases. Refractory cases may benefit from other immunosuppressive drugs such as cyclosporin or chlorambucil.

Disclaimer: Please note that the information provided on this page does not replace the advice of your veterinarian. If you are concerned about your cat’s health in any way, we strongly recommend you seek veterinary advice.