osinophilic granuloma complex (EGC) refers to a group of skin problems in cats. It involves inflammation with an over-representation of one type of the cats white blood cells called an eosinophil. It seems that EGC is a pattern of reaction seen in the skin of cats that has a number of potential causes, most cases are connected to an allergy.

The skin lesions seen with EGC are usually very itchy and made worse by a cat licking them.

There are several forms of the EGC

  • Eosinophilic ulcer or indolent ulcer
    • These occur on the upper lip of the cat, usually towards the front of the lip.
  • Eosinophlic plaque
    • These lesions occur anywhere on the body but are most commonly seen on the tummy and thighs. They are usually round to oval, raised, flat swellings of the skin and appear red. They often ulcerate and are very itchy
  • Eosinophilic granuloma
    • These lesions can occur anywhere on the body, most commonly on the tongue or roof of the mouth, hind legs and foot pads. There is usually an area of raised thickened skin that may be reddened. Hair loss and ulceration are common.


The lesions of EGC have to be differentiated from other skin diseases such as fungal, bacterial or viral infection, skin or oral tumours, abscesses and other causes of swellings. A biopsy should be submitted to the laboratory for microscopic examination. A full clinical examination is required and also a full history of the patient


Once a diagnosis is made it is important to search for underlying causes. Investigations may include flea eradication programs, food trials or trial treatments including medication. Some potential allergens include

  • flea bite
  • mosquito/insects
  • food
  • genetic predisposition
  • airborne substances such as pollen


Treatment depends on the underlying cause as discuss above.  However often a secondary bacterial infection will often be present and antibiotics to treat this infection will help improve the lesions. Corticosteroids are often used to control the symptoms and the duration and dose of steroids will depend on the condition being treated. Anti-histamines or immunosuppressive drugs may also be trialled.

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