Christine Rees, DVM, DACVD
Eosinophilic granuloma complex is a dermatologic condition most commonly seen in cats. Allergies such as food allergy, atopy and insect hypersensitivities have been associated with this syndrome. If the allergic cause for this dermatitis is not found than the EGC is described as being idiopathic.
Draining tracts or fistulous tracts are tract lesions that connect with a central area or focus of inflammation to the skin's surface. Draining tracts are most commonly associated with nodules which are large (greater than 0.5 cm), firm, raised usually circular lesions that extend down into the dermis.
Etiology is a type I hypersensitivity predominantly but a type III and type IV reaction may also occur. Animals are predisposed to develop food allergy through undefined genetic factors.
Several different diagnostic and medical treatment options exist for treating otitis in dogs and cats. It is important that the veterinarian know all of the options that are available so that they can make recommendations to the pet owner.