Causes of vaginal bleeding in prepubescent children differ substantially from the causes in adolescents and adults
Hormonal
Neonatal hormonal withdrawal bleeding
Maternal estrogen stimulates growth of fetus' endometrial lining
After birth, estrogen wanes leading to an endometrial slough that results in a few days of bloody mucoid discharge or light vaginal bleeding
Bleeding is self-limited and requires no treatment
Exogenous estrogen
Precocious puberty
Bleeding out of synchrony with other signs of pubertal development or in a patient under the age of eight years warrants evaluation
Hypothyroidism
Nonhormonal
Trauma
Mechanisms include MVCs, straddle injuries, coitus
Must consider sexual abuse
Tumor
Endodermal sinus tumors and rhabdomyosarcomas (including sarcoma botryoides)
Present almost exclusively in girls under the age of three years with vaginal bleeding
If no obvious cause of bleeding is found in the ED, refer to a pediatric gynecologist for a complete workup including vaginoscopy
Urethral prolapse
Genital warts
Lichen sclerosus
Chronic, mucocutaneous inflammatory disorder of unknown etiology
May have purpura, telangiectasias, and hematomas
Most common presenting symptoms are vulvar and perineal itching, soreness, and pain with defecation
Vulvovaginitis
Poor hygiene, nonspecific irritants
Bacterial infections
Most commonly group A beta-hemolytic streptococcus (Streptococcus pyogenes)
Vaginal foreign body
Neonatal hormonal withdrawal bleeding
Maternal estrogen stimulates growth of fetus' endometrial lining
After birth, estrogen wanes leading to an endometrial slough that results in a few days of bloody mucoid discharge or light vaginal bleeding
Bleeding is self-limited and requires no treatment
Exogenous estrogen
Precocious puberty
Bleeding out of synchrony with other signs of pubertal development or in a patient under the age of eight years warrants evaluation
Hypothyroidism
Maternal estrogen stimulates growth of fetus' endometrial lining
After birth, estrogen wanes leading to an endometrial slough that results in a few days of bloody mucoid discharge or light vaginal bleeding
Bleeding is self-limited and requires no treatment
Bleeding out of synchrony with other signs of pubertal development or in a patient under the age of eight years warrants evaluation
Mechanisms include MVCs, straddle injuries, coitus
Must consider sexual abuse
Endodermal sinus tumors and rhabdomyosarcomas (including sarcoma botryoides)
Present almost exclusively in girls under the age of three years with vaginal bleeding
If no obvious cause of bleeding is found in the ED, refer to a pediatric gynecologist for a complete workup including vaginoscopy
Chronic, mucocutaneous inflammatory disorder of unknown etiology
May have purpura, telangiectasias, and hematomas
Most common presenting symptoms are vulvar and perineal itching, soreness, and pain with defecation
Poor hygiene, nonspecific irritants
Bacterial infections
Most commonly group A beta-hemolytic streptococcus (Streptococcus pyogenes)
Most commonly group A beta-hemolytic streptococcus (Streptococcus pyogenes)
Prepubertal vaginal bleeding
Non-pregnant vaginal bleeding
Nonpregnant vaginal bleeding
Prepubertal pelvic pain
Pregnant
Headache during pregnancy
Vaginal bleeding in pregnancy 
Dysfunctional uterine bleeding