Overview

Trichomoniasis is a common sexually transmitted infection caused by a parasite. In women, trichomoniasis can cause a foul-smelling vaginal discharge, genital itching and painful urination.

Men who have trichomoniasis typically have no symptoms. Pregnant women who have trichomoniasis might be at higher risk of delivering their babies prematurely.

To prevent reinfection with the organism that causes trichomoniasis, both partners should be treated. The most common treatment for trichomoniasis involves taking one megadose of metronidazole (Flagyl) or tinidazole (Tindamax). You can reduce your risk of infection by using condoms correctly every time you have sex.

Symptoms

Many women and most men with trichomoniasis have no symptoms, at least not at first. Trichomoniasis signs and symptoms for women include:

  • An often foul-smelling vaginal discharge — which might be white, gray, yellow or green
  • Genital redness, burning and itching
  • Pain with urination or sexual intercourse

Trichomoniasis rarely causes symptoms in men. When men do have signs and symptoms, however, they might include:

  • Irritation inside the penis
  • Burning with urination or after ejaculation
  • Discharge from the penis

When to see a doctor

See your doctor if you have a foul-smelling vaginal discharge or if you have pain with urination or sexual intercourse.

Causes

Trichomoniasis is caused by a one-celled protozoan, a type of tiny parasite that travels between people during sexual intercourse. The incubation period between exposure and infection is unknown, but it's thought to range from five to 28 days.

Risk factors

Risk factors include having:

  • Multiple sexual partners
  • A history of other sexually transmitted infections
  • A previous episode of trichomoniasis
  • Having sex without a condom

Complications

Pregnant women who have trichomoniasis might: 

  • Deliver prematurely
  • Have a baby with a low birth weight
  • Transmit the infection to the baby as he or she passes through the birth canal

Having trichomoniasis also appears to make it easier for women to become infected with HIV, the virus that causes AIDS.

Prevention

As with other sexually transmitted infections, the only way to prevent trichomoniasis is to abstain from sex. To lower your risk, use condoms correctly every time you have sex.

May 04, 2018
References
  1. Sobel JD. Trichomoniasis. https://www.uptodate.com/contents/search. Accessed Feb. 8, 2018.
  2. Trichomoniasis — CDC fact sheet. Centers for Disease Control and Prevention. http://www.cdc.gov/STD/Trichomonas/STDFact-Trichomoniasis.htm. Accessed Feb. 8, 2018.
  3. Meites E, et al. A review of evidence-based care of symptomatic trichomoniasis and asymptomatic trichomonas vaginalis infection. Clinical Infectious Diseases. 2015;61:S837.
  4. Trichomoniasis. Office on Women's Health. https://www.womenshealth.gov/a-z-topics/trichomoniasis. Accessed Feb. 8, 2018.