Hypotrichosis, also called regional alopecia, is presence of less than normal amount of hair. Both hypotrichosis and alopecia can be congenital or may occur later in the animal's life. Congenital hyptrichosis is the term used to describe animals born without their normal hair or who experience hair loss within the firt month of life. The disorder has been associated with abnormalities of the female reproductive organs, defects in other structures such as teeth, claws, and eyes, and skeletal defects.2 The hair loss is bilateral and usually affects temples, ears, abdomen, back; in some cases it can involve the whole body. Alopecia is later followed by darkening and thickening of the skin and seborrhea. Skin tests reveal normal hair follicle density although follicles are empty or contain keratin debris and fragments of hair shaft.
There may be a sex-linked inheritance as males are predominantly affected, although in young adult Chesapeake Bay Retrievers symmetrical hair loss affects the same areas of the body in male and female dogs. The most frequent causes are hormonal disturbances (increased thyroid function and hyperadrenocorticism), seborrhea, and certain inherited diseases. Genetically-linked hypotrichosis has been reported in the German Shepherd Dog, Dachshund, Cocker Spaniel, Basset Hound, Beagle, Belgian Shepherd, Bichon Frise, French Bulldog, Labrador Retriever, Lhasa Apso, Rottweiler, Toy and Miniature Poodles, Whippet, and Yorkshire Terrier breeds. There is no treatment, but selective breeding might reduce the occurrence of this condition.
- R. Cerundolo, E. A. Mauldin, M. H. Goldschidt, S. L. Beyerlein, K. R. refsal, J. W. Oliver. Adult-onset hair loss in Chesapeake Bay retrievers: a clinical and histological study Veterinary Dermatology 16 (1), 39-46
- Danny W. Scott, D.V.M, William H. Miller, V.M.D, Graig E. Griffin, D.V.M. Small Animal Dermatology