Trichomoniasis
Trichomoniasis is caused by Trichomonas vaginalis, a single-celled parasite that lives in the genital and urinary tract and is passed on during sex.
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Medicines commonly prescribed for Trichomoniasis
For informational purposes only. Always consult a doctor before using any medicine.
Dosage form: TABLET, 250 mgActive substance: metronidazoleManufacturer: Laboratorios Normon S.A.Prescription requiredDosage form: TABLET, 250 mgActive substance: metronidazoleManufacturer: Aurovitas Spain, S.A.U.Prescription required
Trichomoniasis is caused by Trichomonas vaginalis, a single-celled parasite that lives in the genital and urinary tract and is passed on during sex. It is one of the commonest curable sexually transmitted infections and also one of the quietest: roughly half of infected people have no discharge, no pain and no itching at all. A short course of antibiotics clears it, but treatment always involves two people. If only one partner is treated, the parasite simply travels back and forth between them and the infection returns again and again.
Why "nothing is bothering me" means nothing
Having no symptoms is not unusual and not a stroke of luck — it is the ordinary way this infection behaves. About half of infected people notice absolutely nothing and only find out about the parasite when a test picks it up or when a partner falls ill. Someone with no symptoms passes it on exactly as readily as someone with heavy discharge.
Two practical points follow. First, feeling well is not a substitute for a test: if a regular partner has been diagnosed with trichomoniasis, you need testing whether or not anything is troubling you. Second, symptoms can be slow to arrive. It usually takes anywhere from a few days to a month from infection to the first signs, and sometimes the infection sits quietly for months before it announces itself. So "I haven't had any new partners for ages" is not an argument against testing either.
The parasite is passed on through vaginal sex without a condom, through shared sex toys and through close genital contact. It is not passed on by towels, toilet seats, swimming pools or shared crockery — worth knowing, if only so that nobody goes looking for blame where there is none.
What women notice and what men notice
In women trichomoniasis usually produces a visible picture. There is heavy discharge, characteristically yellow-green, sometimes frothy, with an unpleasant strong smell. Alongside it come itching, soreness, redness and swelling around the vaginal opening, discomfort when passing urine and during sex, and sometimes a dull ache low in the abdomen. Symptoms often flare just after a period.
In men things are usually far more discreet. Most often there is nothing at all, and when there is something, it amounts to mild burning or stinging when passing urine, needing to go more often, a scanty discharge from the urethra, or discomfort after ejaculating. These sensations are easy to put down to tiredness or passing irritation, which is exactly why men are so often the ones who carry the infection for years and pass it on without suspecting a thing.
None of these signs belongs to trichomoniasis alone. The same discharge and itching turn up in bacterial vaginosis, thrush, chlamydia and gonorrhoea, and burning on passing urine in men accompanies urethritis of any cause. They cannot be told apart by eye, so treating "by symptoms" here is pointless.
Which test confirms the diagnosis
The diagnosis is made in the laboratory, not by examination. In women a swab is taken from the vagina; in men, a swab from the urethra or a first-catch urine sample. The most sensitive method is a molecular test (PCR): it finds the parasite even when there is very little of it and when there are no complaints at all. Microscopy of a smear is simpler and cheaper, but it misses a proportion of cases, particularly in men, so a negative microscopy result does not rule out the infection when suspicion is strong.
You can be tested without any symptoms whatsoever, simply because there was unprotected sex with a new partner. Taking the sample is not usually painful, and in many settings you can take the swab yourself.
It is worth being checked for other sexually transmitted infections at the same time. Trichomoniasis rarely comes alone: it often sits alongside chlamydia, gonorrhoea or mycoplasma infection, and testing for HIV and syphilis is sensible in this situation in any case. That is one round of samples rather than five separate trips, and it settles a whole cluster of questions at once.
Treatment: one course for two people
Trichomoniasis is treated with antibiotics from the nitroimidazole group, usually metronidazole or tinidazole. The regimen and its length are chosen by the doctor: it may be a short course over several days or a single larger dose. Finish the course even if the discharge and itching disappear on day two — symptoms settling means there are fewer parasites, not that none are left.
Both partners must be treated at the same time, even if the second has no complaints at all and has not been tested. This is not over-caution. Treat one person alone and the infection comes back with the first act of sex, and the second course starts from scratch. Recent partners need treating too; the doctor can explain how to let them know, including without naming you.
Two restrictions apply while treatment lasts. Alcohol is avoided completely for the whole course and for a few days afterwards: combining metronidazole or tinidazole with alcohol produces a severe reaction with nausea, vomiting, palpitations and sharp weakness. And sex is put on hold until both partners have finished the course and a week has passed since the last dose. A condom is not considered reliable protection during those days.
If symptoms are still there weeks later, that more often means reinfection from an untreated partner than a parasite resistant to the drug. A doctor should sort this out and will either repeat the course or switch to a different regimen.
What untreated trichomoniasis can lead to
An infection that causes no trouble is still not harmless. Over time, untreated trichomoniasis can contribute to pelvic inflammatory disease in women — pelvic pain, a raised risk of ectopic pregnancy and damage to the fallopian tubes that can end in infertility. In men the parasite keeps a low-grade urethritis going and sometimes inflammation of the prostate gland.
Two points deserve to be stated separately. Trichomoniasis noticeably raises the likelihood of bacterial vaginosis and of repeated vaginal inflammation. And it raises the risk of catching HIV or passing it on during sex: an inflamed, easily damaged lining lets the virus through more readily than a healthy one. That is one more reason to have the full set of tests and not to postpone treatment.
Trichomoniasis in pregnancy
In pregnancy this infection stops being merely a nuisance. Trichomoniasis in a pregnant woman is associated with a higher risk of premature birth and low birthweight, and with inflammatory complications after delivery. Occasionally the baby picks up the infection while passing through the birth canal.
Trichomoniasis is treated during pregnancy. The medicines used for it are given in pregnancy, and the doctor will choose the regimen with the stage of pregnancy in mind. Turning down treatment "so as not to harm the baby" is a decision that does more harm than protection. The partner is treated at the same time, otherwise the whole thing repeats itself. If you are pregnant or planning a pregnancy and there has been unprotected sex, say so plainly: testing for trichomoniasis and other sexually transmitted infections is best done in advance.
How to avoid catching it again
Having had trichomoniasis leaves no immunity: you can catch it again a month later. What genuinely lowers the risk:
- using an external or internal condom with new or casual partners;
- not passing sex toys between partners unwashed — clean them between uses and cover them with a fresh condom every time;
- having a sexual health screen once a year, and with every change of partner, whether or not anything is wrong;
- if an infection is found, being treated together with your partner and keeping to the break from sex until both of you have finished;
- not using leftovers of someone else's course and not picking medicines off the internet: an under-treated infection does not go away, it just stops being noticeable.
Online consultation
Plenty of people put off the conversation about sexually transmitted infections out of embarrassment, and that time is lost for nothing. An online consultation is convenient precisely here: the doctor will go through your situation calmly, say which tests are worth doing and how long after possible exposure to do them, explain how to prepare, and help you make sense of results you already have.
It is worth getting in touch remotely if unfamiliar discharge or burning has appeared, if a partner has been diagnosed with trichomoniasis or another sexually transmitted infection, if you are pregnant or planning a pregnancy, and also if symptoms have returned after a completed course. The doctor will tell you what to do next and arrange a face-to-face appointment where examination and a swab are needed.
This material is for information only and does not replace medical advice.
Consult with a doctor about Trichomoniasis
Discuss your symptoms and possible next steps with a doctor online.
Online doctors for Trichomoniasis
Discuss your symptoms and possible next steps for Trichomoniasis with a doctor online.
