Cushing's disease results from excessive production of cortisol, a hormone normally produced by the adrenal glands. This excessive cortisol production can result from abnormalities in the pituitary gland that cause excessive hormone secretion by the adrenal glands, by tumors within the adrenal glands themselves, or by a combination of these factors.
Initial signs include swelling of the face (eyelids, lips and muzzle) that progresses to draining pustules and crusts. The earflaps and ear canals are often swollen and ooze pus. The lymph nodes often become swollen, especially those behind the jaw. The lesions may be painful and some puppies are lethargic, have a fever and won’t eat.
Panniculitis often appears as deep nodules that can occur singly or affect multiple areas of the body. The nodules can be firm or soft and mobile. The lesions can eventually become cystic and ulcerate, often draining an oily, yellowish-brown to bloody discharge.
Symptoms usually begin in late puberty or young adulthood. Symmetrical thinning of hair or hair loss commonly occurs on the outer ear flaps, under the neck, on the chest, backs of the thighs, and behind the ears. There is no associated skin inflammation, itch, redness, or rash. In Dachshunds with hairloss on the outer ear flaps, complete hairloss usually occurs by 8-9 years of age and the exposed skin becomes dark/hyperpigmented.
Lesions typically begin along the nasal bridge, around the eyes, and ear pinnae. It is typical for the lesions to spread and occur along the trunk, feet, clawbeds, groin, and footpads.
Lesions occur most commonly on the trunk, the legs, the digits (toe), the scrotum, the lips, the anus, and the nose. The lesions are typically ulcerated or cauliflower-like in appearance, bleed easily and are typically solitary.