These two tables list diseases characterized by hair loss with few if any other signs. Hair loss can mean impaired growth of new hair. It may involve the entire coat, or you may see patches of hair loss on certain parts of the body. In general, hair loss caused by hormonal diseases is symmetric (the same on both sides of the body), while that caused by parasites and other causes is asymmetric.
Hormone-Related Diseases with Hair Loss
- 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 ChowChows, 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 withoutitching. 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.
- Acanthosis nigrans: Mainly in Dachshunds. Hair loss begins in armpit folds and on ears. Black, thick, greasy, rancid-smelling skin.
- Color mutant alopecia (blue Doberman syndrome):Loss of hair over the body, giving a moth-eaten look. Papules and pustules may appear in areas of hair loss. Also affects other breeds.
- Demodectic mange: Localized-Occursin puppies. Hair loss around eyelids, lips, and corners of mouth, occasionally on the legs or trunk, giving a moth-eaten look. Fewer than five patches, up to 1 inch (25 mm) in diameter. Generalized-Numerous patches that enlarge and coalesce. Severe skin problem complicated by pyoderma. Primarily affects young adults. Generalized form is associated with immune deficiencies.
- Nasal solar dermatitis (Collie nose):Loss of hair at junction of nose and muzzle. Can lead to severe ulceration. Affects dogs with lightly pigmented noses. May be part of an autoimmune problem.
- Pressure sore (Callus):Gray, hairless, thickened pad of wrinkled skin, usually over elbows but may involve other pressure points. Caused by lying on hard surfaces. Mostly seen in large and giant breeds.
- Ringworm: A fungal infection. Scaly, crusty circular patches 1⁄2 to 2 inches (12 to 50 mm) across. Patches show central hair loss with a red ring at the periphery. Some cases show widespread involvement.
- Sebaceous adenitis: Seen mainly in Standard Poodles, but does occur in other breeds, including Akitas. Symmetrical loss of hair over face, head, neck, and back. Dandrufflike scales and hair follicle infection can develop.
- Seborrhea: Dry type-Similar to heavy dandruff. Greasy type-Yellow-brown greasy scales that adhere to hair shafts; rancid odor. May occur secondary to other skin problems.
- Vitiligo: Some hair loss, but mostly pigment loss that causes hair to change color. Mostly seen on the face and head. Seen most often in Rottweilers and Belgian Tervuren.
- Zinc-responsive dermatosis: Crusty, scaly skin with hair loss over the face, nose, elbows, and hocks. Cracked feet. Caused by zinc deficiency. Arctic or Northern breeds are most susceptible.
