Overview of Feline Eosinophilic Granuloma Complex
The term eosinophilic granuloma complex (EGC) refers to a group of skin lesions that represent an allergic reaction in the cat’s skin. These occur in three forms, and your cat may have any or all of them. These forms include:
On microscopic examination of skin biopsy specimens, all of these forms of the disease are characterized by accumulation of large numbers of eosinophils, a type of white blood cell found in allergic and parasitic inflammatory disorders.
A common cause is thought to be flea allergy, but atopy, a form of allergy triggered by inhaled environmental allergens such as pollens and dust, and food allergies also can cause EGC lesions in cats. An allergic response to mosquitoes is also suspected.
Female cats may be more likely to be affected than male cats, but only rarely is it found in dogs, such as Siberian huskies.
Diagnosis of Eosinophilic Granuloma Complex in Cats
Diagnostic tests may be needed to diagnose eosinophilic granuloma complex and assess the extent of the disorder and its effects on the cat. Often, a presumptive diagnosis is made based on the clinical appearance of the lesions and their response to treatment. Tests may include:
Treatment of Eosinophilic Granuloma Complex in Cats
Treatment for eosinophilic granuloma complex may include one or more of the following:
Home Care and Prevention
At home, administer as directed all medications prescribed by your veterinarian, and contact your veterinarian if you are having difficulty medicating your pet or if the condition has worsened.
Follow-up appointments are very important because the lesions of eosinophilic granuloma complex often require more than one treatment for complete success.
Preventative measures include flea control, elimination diets to identify food allergens and treatment for inhaled allergens.
In-depth Information on Eosinophilic Granuloma Complex in Cats
Eosinophilic granuloma complex refers to a characteristic allergic skin reaction in cats. Flea allergy is thought to be the most common cause of this type of allergic skin reaction. Allergic reactions to food components, which are allergens that are inhaled into the respiratory system (atopy), and allergic reactions to other insects such as mosquitoes also can result in eosinophilic skin lesions. In unusual cases, an allergic cause cannot be found and a hereditary disorder is suspected.
Eosinophilic plaques usually are found on the abdomen or the inner thighs. They are raised, red lesions that may be glistening in appearance or oozing serum. Eosinophilic plaque lesions are extremely itchy (pruritic) and often are surrounded by broken hairs from constant licking of the area by the cat with its barbed tongue. Other skin diseases that can produce similar lesions include bacterial or fungal infections and some types of skin cancer including mast cell tumors and cutaneous forms of lymphosarcoma.
Eosinophilic granulomas often are found on the backs of the legs, on the roof of the mouth or on the tongue, and on the lower lip causing the cat to have a pouting expression. Lesions on the back of the legs usually are raised, round, and pink or yellow in color. More than one lesion may be present and they tend to occur in a linear distribution along the leg. As with eosinophilic plaques, bacterial and fungal infections and certain types of skin cancer such as mast cell tumor and cutaneous lymphosarcoma can have a similar appearance.
Indolent ulcers, also called rodent ulcers almost always are found on the upper lip and usually are confined to one side. Occasionally, they may be found on both sides of the lip or inside of the mouth. The lesions most often are raised and ulcerated, causing a dramatic change in the appearance of the lip. Indolent ulcers may represent a precancerous lesion and, if untreated, eventually may develop into a malignant skin tumor called squamous cell carcinoma. Once again, bacterial and fungal infections and skin tumors (including mast cell tumor, cutaneous lymphosarcoma and squamous cell carcinoma) are diseases that may result in a similar appearance.
In some cats, more than one type of eosinophilic skin disease can occur simultaneously.
Diagnostic tests may be performed to identify underlying diseases, especially certain types of skin cancer) that may be confused with eosinophilic granuloma complex. Your veterinarian may recommend the following:
Optimal therapy of any serious or persistent medical condition depends on establishing the correct diagnosis. Eosinophilic granuloma complex occurs in several forms and may have several potential underlying causes. If possible, the underlying cause should be identified before specific treatment is recommended. Medication with anti-inflammatory drugs likely will be recommended for affected cats. Your veterinarian will determine if treatment is warranted, and if so which specific medication is indicated.
Methylprednisolone acetate is given every two weeks until lesions are healed. Adverse effects of corticosteroids can occur in cats but are less common and less severe than observed in dogs. Identification and treatment of underlying allergic conditions may be necessary to prevent recurrence of the eosinophilic granuloma complex lesions. Other drugs that suppress eosinophil function may be necessary if corticosteroids are not effective or cannot be tolerated.
Optimal treatment for your cat requires a combination of home and professional veterinary care. Follow–up can be crucial, especially if your cat does not improve as expected. Administer as directed all medications prescribed by your veterinarian. Therapy must be continued until lesions have completely resolved. Alert your veterinarian if you are having difficulty treating your pet.
Recheck appointments are important to the long-term success of treatment. A diagnostic evaluation for underlying allergic disease like atopy or food allergy may be necessary if lesions recur.
Continue a complete flea control program as prescribed by your veterinarian even after the skin lesions have healed, especially in outdoor cats. Observe your cat’s skin and mouth closely. Lesions are more easily treated if treatment is begun early in the disease process.
As most of these cases are related to allergies, especially flea allergy, aggressive flea control is recommended to prevent the occurrence of a granuloma. Other allergies cannot be avoided.