What Causes Vaginal Discharge to Have a Fishy Odor?
Dec 05, 2021
Source: Cainiu Health
Dr. Yan Ying
Introduction
What Causes Vaginal Discharge to Have a Fishy Odor?
A fishy odor in vaginal discharge may be caused by bacterial vaginosis or trichomoniasis. It may also result from gynecological tumors or vulvovaginal candidiasis. Typically, the fishy odor arises from increased vaginal discharge—often yellowish and malodorous—due to bacterial or fungal infection. Women are advised to undergo vaginal secretion testing for accurate diagnosis, followed by targeted treatment.
Normal vaginal discharge (leukorrhea) in women is typically colorless, odorless, and appears either milky white or clear and viscous—resembling egg whites. If the discharge develops an unusual odor or changes in color or consistency, it is often indicative of a gynecological infection. So, what causes vaginal discharge to have a fishy odor? Let’s explore this together.
Causes of Fishy-Smelling Vaginal Discharge
1. Bacterial Vaginosis
Symptoms include increased vaginal discharge with a distinct fishy odor, which often intensifies during or after sexual intercourse due to elevated ammonia levels in the discharge. The discharge is typically thin, homogeneous, or watery in consistency, appearing grayish-white, grayish-yellow, or creamy yellow, and emits a characteristic fishy odor. This odor may also worsen during or immediately following menstruation.
2. Candidal (Yeast) Vaginitis
Discharge may be white or yellowish, usually thick and sticky but occasionally thin. Classic presentations include curd-like or cottage cheese–like discharge. The discharge is typically thick, white, and clumpy—resembling yogurt or coagulated milk. The vaginal walls appear diffusely erythematous, with some areas covered by diphtheritic membrane-like patches. Upon removal of these white plaques, underlying rough, erythematous, eroded surfaces become visible—commonly caused by fungal (Candida) infection. Laboratory examination of the discharge confirms the diagnosis.
3. Trichomonas Vaginitis
Discharge is typically purulent, yellowish, frothy, or resembling rice-water, with a foul, fishy odor. It appears as thin, yellow or yellow-green purulent fluid, sometimes frothy. In addition to generalized vaginal erythema, punctate or strawberry-like hemorrhagic spots are commonly observed on the cervix and vaginal walls. Diagnosis is confirmed via microscopic examination or culture of vaginal secretions. As Trichomonas infection rarely extends beyond the external cervical os, cervical canal secretions typically lack purulent mucus plugs.
4. Gynecologic Malignancies
Vaginal discharge associated with gynecologic tumors may also emit a fishy or even putrid odor. A particularly foul-smelling discharge often signals an underlying malignancy—most commonly cancers of the genital tract (e.g., cervical or endometrial cancer), severe cervical ectropion (formerly termed “cervical erosion”), or advanced endometritis. Especially in postmenopausal women, foul-smelling discharge warrants immediate evaluation for possible malignancy. Women experiencing such symptoms should seek prompt evaluation at a reputable medical facility to rule out tumor-related disease and initiate timely treatment.
The above outlines the primary causes of fishy-smelling vaginal discharge. If a woman experiences abnormal vaginal discharge, it is recommended that she undergo vaginal secretion testing to identify the underlying cause and guide appropriate treatment—often including oral cephalosporin antibiotics. We hope this information is helpful to you.
