Trichomonas symptoms in women: recognising it and getting checked

In women, trichomonas classically causes yellow-green, sometimes frothy discharge with an unpleasant smell, itching and sometimes pain when peeing. That is the textbook picture. In practice a large share of women with trichomonas notice nothing, which is exactly why this STI is often found late.

Trichomonas vaginalis is a single-celled parasite, not a bacterium and not a fungus. That explains why it is treated differently from the infections it resembles.

Which complaints fit trichomonas?

The most described complaints are changed discharge with a yellow-green colour, a strong smell, itching or irritation around the vagina, and sometimes burning when peeing or pain during sex. Frothy discharge gets mentioned often but is far from always present.

Sutton and colleagues found in a US population study that a substantial share of women with trichomonas reported no complaints. Schwebke and Burgess reached the same conclusion in their review: symptoms are not a reliable guide.

Why does trichomonas resemble bacterial vaginosis so closely?

Because both raise vaginal acidity and both can produce a strong smell. In both the pH is often above 4.5, and in both the discharge changes character. The distinction that actually matters is not the colour but whether a parasite is involved.

Only a test can make that distinction.

Say you have already used self-care for a yeast infection 2 times and the complaints keep returning. That pattern, repetition despite treatment, is the moment the assumption itself becomes suspect. The overview bacterial vaginosis, thrush or trichomonas puts all three side by side.

How is trichomonas tested?

With a PCR test that detects the parasite genetic material. In women that usually runs through a vaginal swab you can take yourself. Microscopy of fresh material also exists, but misses a share of infections, while PCR is more sensitive.

A 2022 summary in Clinical Infectious Diseases, prepared during the revision of the US treatment guidelines, describes those sensitivity differences between microscopy and molecular techniques.

If you only want this parasite checked, a separate trichomonas test is enough. If chlamydia and gonorrhoea are also relevant, a chlamydia, gonorrhoea and trichomonas test covers all three at once.

What happens after a positive result?

Trichomonas responds well to medication, and that runs through your GP. The agent usually used is described in the Farmacotherapeutisch Kompas. A 2017 meta-analysis compared a single dose with a longer course in women and found a difference in effect, which is why your doctor makes a choice here.

Important: with trichomonas your partner is usually treated too. Otherwise passing it back and forth is only a matter of time.

That conversation often feels heavier than it is. In men the infection usually runs without complaints, so "I noticed nothing" is not evasion but the normal picture. Read about that in trichomonas in men, and about the question that usually follows in trichomonas without sexual contact.

What if your result is negative but the complaints stay?

Then trichomonas is ruled out and the question of what it actually is stays open. A negative PCR result means this parasite was not found, not that your complaints are imagined. Bacterial vaginosis and candida are not in an STI test, so those two were not assessed at all by the same result.

That is the moment for your GP, not for a fourth self-care product.

In the consulting room the acidity can be measured and material can be examined under a microscope. The NHG describes in its standard on vaginal complaints how that assessment runs. What you bring with you is useful: a negative STI result narrows the list of possibilities considerably.

Take someone who concludes after a negative result that there is nothing left to do. The opposite is true. With the STI side ticked off, the conversation with your GP is shorter and more focused than without it.

How common is trichomonas in the Netherlands?

Less common than chlamydia, but targeted investigation does find it. The RIVM tracks Dutch STI figures in its annual surveillance. Because trichomonas only turns up when someone looked for it, the reported number partly reflects how often testing happens.

For your own situation, a national average says little.

Every blood test result includes a professional assessment from a BIG-registered doctor. For treatment decisions, discuss your results with your GP.

References

• Sutton M, et al. The prevalence of Trichomonas vaginalis infection among reproductive-age women in the United States, 2001-2004. Clinical Infectious Diseases, 2007. PMID: 17968828
• Schwebke JR, Burgess D. Trichomoniasis. Clinical Microbiology Reviews, 2004. PMID: 15489349
• Kissinger PJ, et al. Diagnosis and Management of Trichomonas vaginalis: Summary of Evidence Reviewed for the 2021 Sexually Transmitted Infections Treatment Guidelines. Clinical Infectious Diseases, 2022. PMID: 35416973
• Howe K, Kissinger PJ. Single-Dose Compared With Multidose Metronidazole for the Treatment of Trichomoniasis in Women: A Meta-Analysis. Sexually Transmitted Diseases, 2017. PMID: 27898571
• RIVM, sexually transmitted infections in the Netherlands, annual surveillance report
• Farmacotherapeutisch Kompas, agents for trichomoniasis