Atrophic Vaginitis: This condition is the most common cause of vaginal bleeding in postmenopausal women, especially after a hysterectomy. The decrease in estrogen levels leads to thinning and drying of the vaginal walls, making them more susceptible to bleeding.

Vaginal or Cervical Polyps: These growths can cause bleeding, especially after intercourse or during pelvic exams. Although less common than atrophic vaginitis, they are still a plausible cause in this demographic.
Endometrial Stumps or Residual Endometrium: In cases where the hysterectomy was not a total hysterectomy (e.g., subtotal or supracervical), residual endometrial tissue can continue to bleed, especially if stimulated by estrogen.
Hormone Replacement Therapy (HRT) Side Effects: Women on HRT may experience vaginal bleeding due to the exogenous hormones, which can stimulate the endometrium or vaginal tissue.

Cancer (Vaginal, Cervical, or Uterine Stump): Although rare, any postmenopausal bleeding, including in women post-hysterectomy, warrants a thorough investigation to rule out malignancy. Vaginal, cervical, or uterine stump cancers can present with bleeding and must be considered to ensure timely diagnosis and treatment.
Infection: Certain infections, including those caused by herpes simplex virus or other sexually transmitted infections, can cause vaginal bleeding and must be considered, especially if other symptoms like discharge or pain are present.

Vaginal or Urethral Caruncles: These are benign growths that can cause bleeding, but they are less common and typically present with other symptoms like pain or discomfort.
Foreign Body: The presence of a foreign body in the vagina can cause bleeding, especially if it leads to infection or irritation of the vaginal walls.
Trauma: Accidental or non-accidental trauma to the vaginal area can result in bleeding and should be considered, especially if there are other signs of injury or if the patient's history suggests this possibility.