Differential Diagnosis for Brown Vaginal Discharge
Single Most Likely Diagnosis
- Old blood or menstrual residue: This is often the most common cause of brown vaginal discharge, especially if it occurs around the time of menstruation or after sexual intercourse. The brown color is due to the oxidation of iron in the blood.
Other Likely Diagnoses
- Bacterial vaginosis (BV): BV is a common condition characterized by an imbalance of vaginal bacteria, leading to an overgrowth of harmful bacteria. It can cause a brown, gray, or white discharge with a fishy odor.
- Trichomoniasis: This is a sexually transmitted infection caused by the parasite Trichomonas vaginalis. It can lead to a greenish-yellow or brown discharge with an unpleasant odor.
- Yeast infection: Although typically associated with a white, cottage cheese-like discharge, some yeast infections can cause a brown discharge, especially if there is bleeding or if the infection is not fully treated.
Do Not Miss Diagnoses
- Cervical cancer: Although rare, cervical cancer can cause abnormal vaginal bleeding, including brown discharge, especially after intercourse or between periods. It's crucial to rule out this diagnosis with appropriate screening and testing.
- Endometrial cancer: Similar to cervical cancer, endometrial cancer can cause abnormal uterine bleeding, which may appear as brown discharge. This diagnosis is particularly important to consider in postmenopausal women.
- Pelvic inflammatory disease (PID): PID is an infection of the female reproductive organs that can cause a range of symptoms, including abnormal vaginal discharge. While not always brown, the discharge can be discolored, and PID is a critical diagnosis to consider due to its potential for long-term complications.
Rare Diagnoses
- Foreign body in the vagina: A forgotten tampon or other object in the vagina can cause a foul-smelling, brown discharge due to infection and tissue reaction.
- Vaginal atrophy: Thinning and drying of the vaginal walls, often due to hormonal changes during menopause, can lead to spotting or light brown discharge.
- Genital tuberculosis: A rare condition in many parts of the world, genital tuberculosis can cause a variety of symptoms, including abnormal vaginal discharge, which may be brown in color.