This syndrome describes a group of skin conditions in cats. Most cases are caused by an underlying allergy and can be effectively resolved by treating the allergy. In a few cases more invasive or prolonged treatment is required. Whatever the cause, it is important to seek veterinary advice early to have the best chance of resolution. If your cat has any itchy or sore looking patches on their skin or ulcers on their lip which refuse to heal you should make an appointment with your vet immediately.
Eosinophilic granuloma syndrome is a term used to describe a group of skin conditions in cats which although looking quite different have a similar cause. You might be more familiar with the condition under one of its other names:
- Indolent ulcer or ‘rodent ulcer’: this is an ulceration on the lip – in most cases affecting the top lip. There is no pain or itching associated with the lesion but the ulcers can look quite dramatic.
- Eosinophilic plaque: is a thickened ‘raw’ looking patch of skin. These areas are usually very itchy and your cat may scratch and lick at it constantly. Often the area is wet as the damaged skin oozes a sticky serum. These can be found anywhere on the skin or lips but most often on the abdomen and hind legs. These may become very extensive (up to 7 cm in diameter).
- Eosinophilic granuloma or linear granuloma: these are thickened patches of skin which may be in strips or lumps and can be found anywhere on the skin or in the mouth. Sometimes these are associated with swelling of the chin. No pain or itching is seen with these lesions. This form of the disease is more often seen in adolescent cats.
Eosinophilic granuloma complex is usually the result of an allergic reaction. In most cases this is reaction to flea bites but other allergies such as food, insect (mosquito) bites or other parasitic infections e.g. lice or mange can also be involved. In some cases the underlying cause is a bacterial skin infection. In a few cases, despite extensive investigation no cause can be identified.
If your cat constantly licks at a particular area, check for any sore patches or lumps. If you find any, seek advice from your vet. If your cat has any combination of indolent ulcer, eosinophilic plaque or linear granuloma they are suffering from eosinophilic granuloma complex.
Your vet may well suspect that your cat has eosinophilic granuloma simply from the appearance of the skin changes. Your vet may also take a small sample of nodules (using a needle). This sample can be examined under a microscope and if there is a particularly high number of eosinophils (except in the case of indolent ulcers) present then this may confirm the diagnosis. A skin biopsy will provide the ultimate diagnosis. Some forms of cancer can appear very similar to eosinophilic granulomas.
It is important to identify where possible what is causing the condition. Since parasitic infestation is the most common cause of skin problems your vet will want to be sure that your cat does not have any such infestation. They may use a flea comb or skin scrape to check for fleas or other parasites. Intradermal skin tests can be used to identify allergic reactions to other parasites or environmental factors. To rule out a dietary allergy your vet may ask you to put your cat on a special diet for several weeks.
If an underlying cause is identified the first step in management is to control this problem. If a parasitic infestation (such as fleas) has been identified then initial treatment is directed at controlling the infection with ectoparasitides. Antibiotics can be used to treat any bacterial skin disease. Dietary changes, and insect control are other treatment routes depending on the cause of the eosinophilic granuloma complex.
If there is no response to the control of the underlying problems your vet may prescribe other drugs (such as steroids) to control the allergic reaction. If long-term steroid treatment is needed then your cat will need to be tested for side-effects.
There will usually be an improvement in clinical signs after 3-6 weeks but if the underlying cause cannot be identified and treated. However, long-term management of the symptoms may be required to control the condition if no specific cause is identified.