It's late, something's wrong, and the late-night pharmacy stocks one antifungal cream and a vaguely confident pharmacist. Knowing whether you have a yeast infection or bacterial vaginosis matters: they need different treatments, and using the wrong one can make the right one harder to recognise next time.
Both are extremely common. Both are often confused. Neither is a sign that you've done something wrong — they're both about the vaginal microbiome doing the very normal thing of slipping out of balance.
The fastest way to tell them apart
One simple distinction does most of the work: smell.
- Yeast infections usually don't smell. The discharge is white, thick, and sometimes described as cottage-cheese-like. The dominant feeling is itching, often intense.
- Bacterial vaginosis has a distinctive fishy or sour smell, often stronger after sex. The discharge is thinner, greyish-white, and itching is mild or absent. The dominant feature is smell, not itch.
If your main complaint is "it itches like crazy", lean yeast. If it's "something smells off", lean BV. If both, see a clinician — combination infections are real and need a stool that addresses both.
What's actually happening
The vagina's normal flora is dominated by Lactobacillus species, which keep the pH around 3.8-4.5 (acidic). When that balance shifts, opportunists move in.
Yeast infections (vulvovaginal candidiasis) are caused by overgrowth of Candida, usually Candida albicans. Candida lives quietly in healthy vaginas; it overgrows when conditions favour it — antibiotics that wiped out the bacteria, high blood sugar, hormonal shifts, immune dips.
BV is caused by overgrowth of anaerobic bacteria (commonly Gardnerella vaginalis) replacing the protective Lactobacilli. The pH rises above 4.5 and the bacteria release the volatile compounds responsible for the characteristic smell.
The symptom comparison table
| Symptom | Yeast Infection | BV |
|---|---|---|
| Itching | Often intense | Mild or none |
| Discharge consistency | Thick, white, clumpy | Thin, watery, greyish |
| Smell | Usually none | Fishy, especially after sex |
| Burning | Common | Less common |
| Pain with sex | Common | Sometimes |
| External redness | Often | Less common |
What sets each one off
Yeast infections often follow:
- A recent course of antibiotics
- Hormonal changes (pregnancy, certain contraceptives, the luteal phase)
- High blood sugar or uncontrolled diabetes
- Tight synthetic underwear in heat — Candida loves warm and moist
- Immune suppression (illness, steroid use)
BV often follows:
- New sexual partners (BV behaves a bit like an STI but isn't classified as one)
- Douching — a known disruptor of vaginal flora
- Strong-scented soaps or "feminine wash" products in the genital area
- Menstruation (blood raises pH transiently)
- Use of certain IUDs in some users
Treatment, briefly
Yeast infections respond to antifungal creams (clotrimazole, miconazole) — over the counter, applied for 3-7 nights — or a single oral fluconazole tablet, prescription-only in South Africa. The cream is usually enough for a first or occasional infection. Recurring yeast may need a longer maintenance course.
BV needs antibiotics — usually metronidazole (oral or vaginal gel) or clindamycin (cream). It does not respond to antifungal creams. This is the main reason getting the diagnosis right matters: a course of clotrimazole on BV does nothing while the smell hangs around.
Both treatments have caveats:
- Metronidazole + alcohol = very unpleasant. Don't drink during the course.
- Antifungal cream can weaken latex condoms and diaphragms. Use other contraception during treatment.
- Recurrent BV often comes back; some clinicians prescribe maintenance therapy.
When to skip the pharmacy and go to a doctor
Self-treating an obvious yeast infection is fine. Self-treating BV with the wrong cream isn't. See a clinician if:
- It's your first-ever episode and you're not sure what it is
- You've treated yourself and the symptoms haven't cleared in 3-4 days
- Symptoms are recurring (more than 4x a year)
- You have lower-belly pain, fever, or unusual bleeding
- You're pregnant — both BV and yeast are managed slightly differently in pregnancy
- You suspect an STI overlap (trichomoniasis can mimic both, and is sexually transmitted)
Trichomoniasis — the third option
If you're sure it isn't yeast and the symptoms don't quite match BV either, the third common culprit is trichomoniasis, a sexually transmitted parasitic infection. It can cause yellow-green frothy discharge, itching, and a smell that doesn't quite fit either pattern. It's diagnosed via a swab and treated with metronidazole. Both partners need treatment.
Prevention that actually works
The vaginal microbiome doesn't need much from you — it does its own job when left alone. The interventions with the best evidence:
- Don't douche. Ever. The vagina is self-cleaning. Douching strips protective bacteria and is a leading cause of recurrent BV.
- Skip "feminine wash" products in the vulva. Plain water is fine. Mild soap on the outside only is fine. Don't put anything inside.
- Cotton underwear and breathable clothing — especially if yeast is your recurring problem.
- Probiotics with Lactobacillus crispatus or rhamnosus — modest evidence, low risk, may help recurrent BV. Brand-specific.
- Condoms with new partners — semen is alkaline, and consistent condom use is associated with lower BV rates.
- Manage blood sugar if you're prone to recurrent yeast and have any insulin resistance.
The bottom line
Itch without smell, thick white discharge → most likely yeast → antifungal cream is fine.
Smell without much itch, thin grey discharge → likely BV → needs antibiotics, not antifungal.
Both at once, recurring, or anything that doesn't fit cleanly into one box → swab at a clinic. The right diagnosis upfront saves a week of guessing.
If you're pregnant or have any pelvic pain, fever, or bleeding, please see a clinician rather than self-treating.
