Quick answer. Three infections cause most vaginal symptoms in Singapore. Thrush (candida) gives thick, white, odourless discharge with itching; bacterial vaginosis (BV) gives thin, greyish discharge with a fishy smell; trichomoniasis gives frothy, yellow-green discharge and is sexually transmitted. Thrush and BV are not STIs, though they can be triggered by sex, antibiotics or hormonal changes. Antifungal pessaries or fluconazole treat thrush; metronidazole treats BV and trichomoniasis. You can try OTC antifungals for a first, typical thrush episode, but see a doctor if it is your first time, you are pregnant, symptoms persist or recur (4+ a year), or you may have an STI. A vaginal swab confirms the cause.
Vaginal discharge, itching and odour are among the commonest reasons women see a doctor, and the symptoms of different infections overlap a lot. Three conditions — vaginal thrush (candida), bacterial vaginosis (BV) and trichomoniasis — account for the great majority of cases.
This guide explains how to tell them apart, when an over-the-counter product is reasonable versus when you should be seen, what to do about recurrent infections, and why some — but not all — vaginal infections call for STI testing. It is general information and not a substitute for assessment by a doctor or pharmacist.
At a glance
| Feature | Thrush (candida) | BV / Trichomoniasis |
|---|---|---|
| Discharge | Thick, white, 'cottage cheese' | BV: thin grey-white | Trich: frothy yellow-green |
| Odour | Usually none | BV: fishy smell | Trich: often strong/foul |
| Itch / soreness | Prominent itching and soreness | Variable; trich can itch, many have no symptoms |
| Sexually transmitted? | No | BV: no | Trichomoniasis: yes |
| Typical treatment | Antifungal pessary or fluconazole | Metronidazole (oral or vaginal) |
| Partner treatment | Not usually needed | BV: no | Trichomoniasis: yes, partner must be treated |
Thrush (vaginal candidiasis)
Thrush is caused by overgrowth of a yeast, usually Candida albicans, which normally lives harmlessly on the skin and in the vagina. It typically causes thick, white, odourless discharge (often described as cottage-cheese-like) with itching, soreness, redness and discomfort during sex or when passing urine.
Common triggers include antibiotics, pregnancy, poorly controlled diabetes, a weakened immune system and some hormonal contraceptives. Thrush is not a sexually transmitted infection. Treatment is with antifungal pessaries or cream inserted into the vagina, or a single dose of oral fluconazole (not suitable in pregnancy or breastfeeding — use pessaries instead).
Bacterial vaginosis (BV)
BV is the most common cause of abnormal discharge in women of reproductive age. It happens when the normal protective Lactobacillus bacteria are replaced by an overgrowth of other bacteria. The classic sign is thin, greyish-white discharge with a fishy odour, which is often more noticeable after sex. Some women have no symptoms.
BV is not classed as an STI, although sexual activity can disturb the vaginal balance and trigger it. It is treated with metronidazole (or clindamycin), taken by mouth or used vaginally. Routine partner treatment is not usually needed. BV in pregnancy is treated because it can be associated with complications.
Trichomoniasis
Trichomoniasis is caused by a parasite, Trichomonas vaginalis, and is sexually transmitted. It can cause frothy, yellow-green, foul-smelling discharge, itching, soreness and discomfort passing urine — but many people have no symptoms at all and can pass it on unknowingly.
It is treated with oral metronidazole, and sexual partners must be tested and treated at the same time to prevent reinfection. Because it is an STI, a diagnosis of trichomoniasis is also a reason to consider testing for other sexually transmitted infections.
OTC vs. seeing a doctor
For a typical, recurring thrush episode that you have had diagnosed before, an over-the-counter antifungal (pessary, cream or tablet) from a pharmacy is reasonable, and a pharmacist can advise.
See a doctor instead if:
- It is your first ever episode, or you are not sure of the diagnosis
- You are pregnant or breastfeeding
- Symptoms do not settle after treatment, or come back quickly
- You have a fishy smell, frothy or coloured discharge (suggesting BV or trichomoniasis, which need antibiotics, not antifungals)
- You have pelvic pain, fever, bleeding, or could have an STI
- You are under 16 or over 60, diabetic, or have a weakened immune system
Recurrent infections and when STI testing matters
Recurrent thrush (four or more episodes in a year) deserves a doctor’s review to confirm the diagnosis, look for triggers such as diabetes, and consider a longer maintenance course of antifungals. Recurrent BV is common too and can be managed with repeat or longer courses.
Thrush and BV are not STIs, so a single typical episode does not by itself mean you need STI testing. However, STI testing is important if you have a new or multiple partners, symptoms suggesting trichomoniasis (which is sexually transmitted), unusual bleeding or pelvic pain, or if a partner has an STI. A vaginal swab in a clinic can confirm whether the cause is fungal, bacterial or parasitic, which ensures the right treatment and reduces recurrence.
Self-care and gentle prevention
Some everyday habits reduce irritation and may lower the chance of recurrent thrush and BV, though they are not a substitute for treatment when an infection is present. Wash the external area with water or a plain, unperfumed cleanser, and avoid douching or scented soaps, sprays and wipes, which disturb the natural balance. Choose breathable cotton underwear, change out of wet swimwear or sweaty clothing promptly, and wipe from front to back. There is no need to clean inside the vagina, which is self-cleaning. If you are prone to thrush after antibiotics or around your period, mention this to your doctor or pharmacist.
Special situations
In pregnancy, oral fluconazole is generally avoided, so thrush is treated with antifungal pessaries or cream instead; BV in pregnancy is treated because it can be associated with complications. Always tell the clinician or pharmacist if you are pregnant or breastfeeding. Recurrent symptoms, diabetes, a weakened immune system, or being under 16 or over 60 are reasons to be assessed by a doctor rather than self-treating.
Common questions
Can I just buy something from the pharmacy?
For a typical, previously diagnosed thrush episode, an over-the-counter antifungal is reasonable. See a doctor if it is your first episode, you are pregnant, symptoms persist or recur, or the discharge has a fishy smell or odd colour.
Do I need to treat my partner?
Not usually for thrush or BV. For trichomoniasis, which is sexually transmitted, partners must be tested and treated to prevent reinfection.
When should I have an STI test?
Consider testing if you have a new or multiple partners, symptoms suggesting trichomoniasis, unusual bleeding or pelvic pain, or if a partner has an STI.
Related guides
- Best Gynaecology Clinics in Singapore — our editorial shortlist
- gynaecology clinics directory
- Heavy & painful periods
- Ovarian cysts
- Contraception & birth control
Sources
- HealthHub (Singapore) – Vaginal Thrush
- SingHealth – Vaginitis
- World Health Organization – Trichomoniasis
- HealthXchange (SingHealth) – Women's Health
Part of our Women’s health & gynaecology guides · Browse all health topics