Eosinophilic Granuloma Complex (EGC) is a cat skin condition characterized by a group of skin lesions. Eosinophils are white blood cells that are part of the allergic response. When the cat's body comes into contact with an allergen, these busy little cells are sent to the area to try and fight the allergen. In EGC, eosinophils are like lingering house-guests in that they continue to stay in the area and eventually cause problems long after the allergen is gone. Cats being cats will usually over-groom the area, and the constant licking will exacerbate inflammation. Allergens can be anything including but not restricted to flea saliva, various foods, grasses and pollens. Essentially, EGC is an extreme form of an allergy.