Trichomoniasis

Trichomoniasis is a common sexually transmitted infection (STI) that affects both women and men, although symptoms are more common in women.

Trichomoniasis is caused by the single-celled parasite, Trichomonas vaginalis. The vagina is the most common infection site in women, and the urethra (urine canal) is the most common infection site in men.

The parasite is sexually transmitted through penis-to-vagina intercourse or vulva-to-vulva (the genital area outside the vagina) contact with an infected partner. Women can acquire the disease from infected men or women, but men usually contract it only from infected women.

Symptoms

• Vaginal discharge.
• Vaginal odor.
• Discomfort during intercourse.
• Painful urination.

Complications

The genital inflammation caused by trichomoniasis can:

• Increase a woman’s susceptibility to HIV infection.
• Increase the chance that an HIV-infected woman passes HIV to her sex partner(s).
• Cause inflammation of fallopian tubes.
• Cause premature or low-birth-weight babies.

Prevention

The best way to avoid transmission of sexually transmitted diseases is to abstain from sexual contact or to be in a long-term mutually monogamous relationship with a partner who is known to be uninfected.

Latex male condoms, when used consistently and correctly, can reduce the risk of trichomoniasis transmission.

Any genital symptom, such as discharge or burning during urination or an unusual sore or rash, should be a signal to stop having sex and to consult a healthcare provider immediately. A person diagnosed with trichomoniasis (or any STI) should receive treatment and notify all recent sex partners so partners can also be treated.

Treatment

Trichomoniasis can usually be cured with the prescription drug metronidazole, given by mouth in a single dose.

Symptoms in infected men may disappear within a few weeks without treatment. However, an infected man, even a man who has never had symptoms or whose symptoms have stopped, can continue to infect or reinfect a female partner until he’s been treated.

Therefore, partners should be treated at the same time. If you’re being treated for trichomoniasis, you should avoid sex until you and your sex partner(s) complete treatment and have no symptoms. Metronidazole can be used by pregnant women.

Having trichomoniasis once does not protect you from getting it again. Following successful treatment, you can still be susceptible to reinfection.

Last Reviewed: September 2019