Trichomoniasis

This common sexually transmitted infection is caused by a parasite. Lower your risk by using condoms when you have sex.

Update Date: 01.07.2025

Overview
Symptoms
When to see a doctor
Causes
Risk factors
Complications
Prevention
Diagnosis
Treatment
Preparing for your appointment
Overview
Symptoms
When to see a doctor
Causes
Risk factors
Complications
Prevention
Diagnosis
Treatment
Preparing for your appointment

Overview

Trichomoniasis is a common sexually transmitted infection. A parasite causes it. The parasite can spread through genital touching and sex without a condom.

In women, trichomoniasis can cause a foul-smelling vaginal discharge, genital itching and painful urination. Men who have trichomoniasis often have no symptoms. But it's possible to spread the trichomoniasis parasite even when a person doesn't have symptoms.

Trichomoniasis can raise the risk of getting or spreading other sexually transmitted infections, including HIV. And pregnant people who have trichomoniasis might be at higher risk of having their babies early. This is called premature birth.

Treatment for trichomoniasis involves taking medicine called antibiotics. To prevent being infected again, all sexual partners should be treated at the same time.

You can lower your risk of trichomoniasis by using a new condom correctly each time you have sex. If you're in a new relationship, you and your partner should get tested for sexually transmitted infections. Then talk about your results.

Symptoms

Trichomoniasis symptoms may start about 5 to 28 days after you get the infection. Or they may start later.

Many people don't have symptoms. But when symptoms happen, they are different for men and women.

In women, trichomoniasis symptoms include:

  • Thin or frothy discharge from the vagina. This fluid has a foul smell. And it might be clear, white, yellow or green.
  • Genital burning, soreness, itching or change in skin color.
  • Pain with urination or sex.
  • Pain in the lower stomach area.

In men, trichomoniasis rarely causes symptoms. But when symptoms happen, they can include:

  • Itching or irritation inside the penis.
  • Burning with urination or after the penis releases semen.
  • Clear or pus-like discharge from the penis.

The parasite that causes trichomoniasis can be spread even if you don't have symptoms.

When to see a doctor

See your healthcare professional if you have any symptoms of trichomoniasis. Also talk with your healthcare professional if you become aware that a sexual partner has the infection.

Causes

Trichomoniasis is caused by a tiny parasite called Trichomonas vaginalis. The parasite passes between people during genital contact, including vaginal, oral or anal sex. The parasite often passes from a penis to a vagina, or from a vagina to a penis. It also can pass from a vagina to another vagina.

Most often, the parasite infects the lower genital tract. In women, this includes the:

  • Vagina.
  • Outer part of the genitals, called the vulva.
  • Opening of the uterus, called the cervix.
  • Urinary opening, called the urethra.

In men, the parasite infects the inside of the penis. This is called the urethra.

Risk factors

Risk factors for trichomoniasis include having:

  • Sex without a condom.
  • More than one sexual partner at a time.
  • A history of other sexually transmitted infections.
  • A past bout of trichomoniasis.
  • Washing or cleaning out the vagina with water or other mixtures of fluids. This is called douching.
  • Habits that can lead to risky behavior, such as drinking too much alcohol or using drugs.

Complications

Pregnant people who have trichomoniasis might:

  • Deliver their babies too early, also called premature birth.
  • Have a baby with a low birth weight.
  • Give the infection to the baby as the baby passes through the birth canal.

Having trichomoniasis causes swelling called inflammation in the genital area. This may make it easier for other sexually transmitted infections to enter the body or to pass them to others. Trichomoniasis also seems to make it easier to become infected with HIV. HIV is the virus that can lead to AIDS.

Trichomoniasis also is linked with higher risks of:

  • Cancer of the prostate or cervix.
  • Swelling, also called inflammation, of the prostate gland. This condition is known as prostatitis.
  • Swelling of the epididymis, the coiled tube above and behind the testicles that stores and transports sperm. This condition is called epididymitis.
  • Swelling of the bladder, also called cystitis.

Without treatment, trichomoniasis infection can last for months to years.

Prevention

You can prevent trichomoniasis by not having sex. Or if you're sexually active, you can take the following steps to lower your risk:

  • Get tested for sexually transmitted infections. Ask any sexual partners to get tested too. Then talk about your results.
  • Think about choosing to be in a long-term relationship with a partner who also doesn't have trichomoniasis.
  • Use condoms correctly each time you have sex.
  • Put a condom on before the penis touches the vagina, mouth or anus.
  • Don't douche. Douching removes some healthy bacteria in the vagina that help prevent infections.
  • Don't drink too much alcohol or use illegal drugs. Drinking a lot of alcohol or using drugs might lead to risky behavior. That, in turn, could raise your risk of a sexually transmitted infection.

Diagnosis

Your healthcare professional may find, also called diagnose, trichomoniasis with an exam of the genitals and lab tests.

Your healthcare professional may use a cotton swab to collect a sample of fluid from your vagina or penis. The sample is then checked under a microscope. If the parasite can be seen, no other tests are needed.

If the test doesn't show the parasite, your healthcare professional still may think you could have trichomoniasis. When this happens, other tests may be done. A lab can do genetic testing of your fluid sample. Or the lab can find out if the parasite can be grown in a sample of your genital discharge or urine. This is called a culture test.

If you have trichomoniasis, your healthcare professional likely will test you for other sexually transmitted infections as well. That way, you can get treatment for any other diseases that are found.

Treatment

Treatment of trichomoniasis involves taking medicine called an antibiotic. Antibiotics are best known for treating infections caused by bacteria. But certain antibiotics treat infections caused by the trichomoniasis parasite. Treatment can be given during pregnancy. Options may include:

  • One large dose. Your healthcare professional may have you take one dose of medicine by mouth. Antibiotics that treat trichomoniasis include metronidazole (Flagyl), tinidazole (Tindamax, Tinidazole) and secnidazole (Solosec).

    Metronidazole can be taken during pregnancy. Tinidazole and secnidazole usually are not given to pregnant people. More research is needed on their safety during pregnancy.

  • More than dose. Your healthcare professional may recommend a few lower doses of metronidazole or tinidazole. You take the pills two times a day for seven days.

    To help gid rid of the infection, keep taking this medicine for the full time that your healthcare professional prescribed the drug. Take it as exactly as prescribed even if you start to feel better after a few days. If you stop using this medicine too soon, your infection may not go away completely.

All sex partners that you have need treatment at the same time. This keeps you from getting the infection again, also called reinfection. Do not have sex until you and your partner have finished the treatment and the symptoms have gone away. Tell your healthcare professional if symptoms don't go away after treatment.

Drinking alcohol during and for a few days after treatment can cause upset stomach and vomiting. Don't drink alcohol for 72 hours after taking metronidazole or tinidazole, or 48 hours after taking secnidazole.

Your healthcare professional may test you for trichomoniasis once more after treatment. This is done to check whether the infection is gone and that you haven't gotten infected again. Women often are tested 3 weeks to 3 months after treatment. Men usually are not tested again unless they have trichomoniasis symptoms.

Even if you've had treatment that gets rid of trichomoniasis, it doesn't protect you for life. You can get trichomoniasis again if you're exposed to someone with the infection.

Preparing for your appointment

Your family healthcare professional or gynecologist can diagnose and prescribe treatment for trichomoniasis. So can a medical practitioner at an urgent care center.

What you can do

Before the appointment, make a list that includes:

  • A detailed description of your symptoms, including when they started.
  • Any sexually transmitted infections you've had.
  • The number of sexual partners you've had during the past few years.

What to expect from your doctor

Your healthcare professional may do a pelvic exam to check your lower genital tract, including your vagina. A sample of urine or other fluid may be collected from inside your vagina or penis for testing.

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