Vaginal or vulvar symptoms — discharge, itching, odor, burning, or pain — most often trace back to one of a handful of causes: the STIs chlamydia, gonorrhea, and trichomoniasis, and the non-STI conditions bacterial vaginosis and a vaginal yeast infection. They overlap too much to tell apart by sight. A test is what names which one it is, if any.
Chlamydia trachomatis
Neisseria gonorrhoeae
Trichomonas vaginalis
Vaginal bacterial imbalance
| Item | Value |
|---|---|
| Chlamydia | curable — Chlamydia trachomatis |
| Gonorrhea | curable — Neisseria gonorrhoeae |
| Trichomoniasis | curable — Trichomonas vaginalis |
| Bacterial vaginosis (BV) | curable — Vaginal bacterial imbalance |
Which STIs cause vaginal or vulvar symptoms
Several sexually transmitted infections produce vulvovaginal symptoms, and the ones searchers worry about most are often the quietest. A normal-looking exam doesn't rule them out. So get screened instead of relying on what you can see.
Chlamydia
Chlamydia is caused by the bacterium Chlamydia trachomatis, and it's notoriously silent — roughly three quarters of infected women have no symptoms at all CDC chlamydia. When symptoms do appear, they usually show up within one to three weeks of exposure as abnormal vaginal discharge and burning on urination. If the infection climbs upward into the uterus and fallopian tubes, it can cause lower abdominal or low-back pain, fever, pain during intercourse, and bleeding between periods, a pattern that signals possible pelvic inflammatory disease, which can damage fertility. Because it hides so well, chlamydia is a strong argument for routine screening even when you feel fine.
Gonorrhea
Gonorrhea, caused by the bacterium Neisseria gonorrhoeae, can infect the genitals, rectum, and throat. In women, most infections produce no symptoms CDC gonorrhea; when they do, you may have painful or burning urination, increased vaginal discharge, and bleeding between periods. The clinical picture overlaps almost completely with chlamydia, which is why labs frequently test for both from one sample. Untreated gonorrhea carries the same upward-spread risk to the reproductive organs, so a missed case can do harm even when it feels like nothing.
Trichomoniasis
Trichomoniasis is caused by the protozoan parasite Trichomonas vaginalis and is the most common curable STI. About 70% of infected people have no signs or symptoms CDC trich. When women do notice it, the pattern is fairly distinctive: itching, burning, redness or soreness of the genitals, discomfort urinating, and a clear, white, yellowish, or greenish discharge that may carry a fishy smell. Symptoms can appear roughly 5 to 28 days after infection, or much later. That fishy odor overlaps with BV, so you can't tell the two apart by smell alone; reviewing the full set of trichomoniasis symptoms helps, but a test confirms it.
Bacterial vaginosis (BV)
Bacterial vaginosis isn't an STI. It's an imbalance of the vaginal microbiome, where the protective Lactobacillus bacteria that keep the vagina acidic get crowded out by anaerobic species. It's the most common vaginal condition in women ages 15 to 44 CDC BV. The hallmark is a thin white or gray discharge with a strong fish-like odor, often most noticeable after sex, sometimes with itching or burning. Many people with BV have no symptoms at all. Sexual activity can disrupt the balance that triggers it, so understanding how to prevent bv is part of managing recurrences.
Vaginal yeast infection (candidiasis)
A vaginal yeast infection is a fungal overgrowth, usually of Candida albicans, and it's not typically acquired through sex, so it isn't an STI CDC candidiasis. The telltale combination is vaginal itching or soreness with a thick, white discharge often described as cottage-cheese-like, sometimes with pain during sex or burning when urinating. Mild cases stay subtle; severe ones bring redness, swelling, and small cracks in the vaginal wall CDC yeast signs. Antibiotics, pregnancy, and diabetes all tilt the odds toward yeast, so learning how to prevent yeast infections is worthwhile if you get them repeatedly.
When it's not an STI — and not an infection at all
Plenty of vulvar symptoms come from skin and not from a microbe. Eczema (an itchy, inflamed-skin condition) can affect the vulva. Lichen sclerosus (a chronic condition that produces thin, white, often itchy patches of skin) needs medical attention because it doesn't resolve on its own. Contact dermatitis — irritation from soaps, detergents, lubricants, or fragranced products — mimics infection with itching and redness but has no discharge or odor. When itching dominates and there's no abnormal discharge or smell, a skin cause moves up the list.
How to tell them apart
A few features point in useful directions, even though none is definitive. A strong fishy smell leans toward BV or trichomoniasis, while yeast usually has little or no odor. Discharge texture helps too: thick and white suggests yeast, thin and gray suggests BV, frothy or greenish suggests trichomoniasis. Itching with normal-looking discharge points toward yeast or a skin condition. Bleeding between periods or pain with sex raises concern for chlamydia or gonorrhea spreading upward. These patterns blur constantly, and the STIs are frequently silent, so the symptom narrows the list while a test closes it.
Side-by-side comparison
| Cause | STI? | Typical discharge | Odor | Other clues |
|---|---|---|---|---|
| Chlamydia | Yes | Abnormal; often none | Not typical | Usually silent; burning urination, bleeding between periods if it spreads |
| Gonorrhea | Yes | Increased; often none | Not typical | Mostly silent; painful urination, bleeding between periods |
| Trichomoniasis | Yes | Clear, white, yellow or green; can be frothy | Fishy possible | Itching, soreness, genital redness; ~70% have no symptoms |
| Bacterial vaginosis | No | Thin, white or gray | Strong fishy, worse after sex | Microbiome imbalance; many have no symptoms |
| Yeast infection | No | Thick, white, cottage-cheese-like | Little or none | Intense itching; normal vaginal pH |
How it's tested
Testing is what turns a guess into an answer. NAAT (nucleic acid amplification testing) is the preferred method for chlamydia, gonorrhea, and trichomoniasis — for gonorrhea its sensitivity is usually above 90% with specificity around 99% CDC gonorrhea testing, and the trichomoniasis assay runs about 95–100% sensitive CDC trich Tx. BV is diagnosed by Amsel criteria, a Nugent score on Gram stain, or molecular tests, and yeast is confirmed with a wet-prep microscope slide or culture, with a normal vaginal pH helping separate it from BV CDC STI Guidelines, 2021. In practice that means a urine sample, a self-collected swab, or a quick exam depending on what's suspected — free or low-cost at health departments, Planned Parenthood, and Title X clinics, with results usually back in a few days. See your options to get tested.
What to do next
Don't reach for a leftover antibiotic or treat a yeast infection blind. The conditions look alike, and the wrong treatment delays the right one. Get a test, then treat based on the result; chlamydia, gonorrhea, and trichomoniasis are all curable, and so are BV and yeast. If you tested soon after a possible exposure, check when to test after exposure to be sure you didn't test too early to catch it.
Red flags — when to get seen urgently
- Fever with lower abdominal or pelvic pain — a possible sign infection has spread to the reproductive organs.
- Severe pain, heavy bleeding, or bleeding that isn't your period.
- Symptoms during pregnancy, which need prompt evaluation.
- Open sores, ulcers, or rapidly worsening swelling and redness.
- Symptoms that don't improve after treatment, or that keep coming back.