Auricular Chondritis, Rat

Abstract

The gross appearance of experimentally induced lesions resembles that of naturally occurring ones. The lesions are seen in both ears. In the early stages of the natural disease the affected ears show no clinically detectable abnormality. Slight focal nodular or diffuse swelling and thickening, with or without erythema, develops as the lesions progress. These signs may partially or completely disappear. Nodule size and thickening increase up to a certain point and then stop without further change. The thickness of the ears ranges up to many times normal (Fig. 131). Subsequently, the ears become irregularly thickened (Fig. 132), white, firm, nodular, and droopy (Fig. 133) or remarkably deformed and misshapen (Fig. 134), resembling “cauliflower” or “wrestler” ears in man. Generally, there is no apparent change on the surface of the skin of the affected pinnae but, in some rats, the skin may be scaly, alopercic, or ulcerated.