Cortisone excess: Symmetric hair loss over trunk and body. Abdomen is pot bellied and pendulous. Seen with Cushing’s syndrome. In some cases, the dog is taking steroids.
Growth hormone-responsive alopecia: Bilaterally symmetric hair loss, mainly in male dogs. Begins around puberty. More prevalent in certain breeds, including Chow Chows, Keeshonds, Pomeranians, Miniature Poodles, Airedales, and Boxers.
Hyperestrogenism (estrogen excess): Occurs in females and males. Bilateral symmetric hair loss in perineum and around genitals. Enlarged vulva and clitoris; in males, pendulous prepuce.
Hypoestrogenism (estrogen deficiency): Occurs in older spayed females. Scanty hair growth and thinning coat, initially around vulva and later over entire body. Skin is smooth and soft, like a baby’s.
Hypothyroidism: Most common cause of bilaterally symmetric hair loss without itching. Coat is thin, scanty, and falls out easily. Involves the neck beneath the chin to the brisket, sides of body, backs of thighs, and top of tail.