In 1953 Coffin and Munson gave an excellent review of the endocrine diseases of the dog associated with bilateral distribution of hair loss. These three endocrine conditions are (1) Sertoli cell tumor of the testis, (2) hypothyroidism and (3) an abnormal pituitary-adrenal state known as "canine Cushing's syndrome." The bilaterally symmetrical alopecia caused by these endocrine disturbances is seen infrequently.