Hyperestrogenism in dogs has several etiologies, among them, the result of the excessive production of estrogen by testicular or ovarian tumors. It is also described that it may have its origin due to an imbalance between the androgen and estrogen hormones. As a result of hyperestrogenism, clinical dermatoses are manifested, such as symmetrical bilateral alopecia, thinner coat, easily detachable, variable hyperpigmentation. The diagnosis is based on history, anamnesis, clinical signs, testicular ultrasound, hormonal measurement of serum estrogens and histopathological examination. The treatment of choice is orchiectomy. The aim of the present study is to report the occurrence of a dermatosis secondary to hyperestrogenism in a young dog.