Background: Sex hormone dermatoses are uncommon in dog and causes overproduction of one or more of the sex hormones or exogenous administration. Ovarian cyst-induced hyperestrogenemia increased cortisol, hypertestosteronemia, and skin lesions mostly underwent undiagnosed and untreated. This case was documented as clinical pathological changes, diagnosis, and treatment of sex hormone imbalance-induced dermatosis due to an ovarian follicular cyst in a Labrador Retriever bitch. Methods: This clinical investigation was carried out in the month of April’2022 at Veterinary Clinical Complex, Veterinary College and Research Institute, Tirunelveli with a history of prolonged proestrus bleeding, perineal pruritus with reddening, swelling, and enlargement of the vulva. Vaginal exfoliative cytology, hormonal assay, ultrasonography, histopathology of skin, and haemato-biochemistry were performed. Result: Physical examination revealed hyperpigmentation and hyperkeratinization of the skin. Vaginal exfoliative cytology and progesterone assay revealed cytological estrus. Ultrasonography revealed greater than 10 mm-sized anechoic structures in both ovaries along with uterine endometrial hyperplasia. Hormonal analysis revealed hyperestrogenemia and increased cortisol and testosterone. A biopsy of the perineal skin revealed hyperplasia and hyperkeratosis. The case was confirmed as sex hormone imbalance-induced dermatosis due to an ovarian follicular cyst. The animal was treated with two shots of Inj. hCG 500IU in 48 hrs interval followed by OHE after three months.