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Symptoms and Signs of Trichomoniasis

Doctor's Notes on Trichomoniasis

Trichomoniasis (commonly referred to as Trich) is a common sexually-transmitted disease. It is caused by an infection with the parasite known as Trichomonas vaginalis. In women it affects the vagina, vulva, urethra, or cervix. In men, trichomoniasis affects the urethra in the penis.

Trichomonas infection may not cause any symptoms or signs, but if a person has the infection, they can still spread it to other people even if they do not have symptoms themselves. When the condition does cause symptoms, the associated symptoms and signs include redness, burning, and itching of the genital areas, pain with urination (dysuria), and an abnormal vaginal or penile discharge that has been described as foul-smelling and gray, green, yellow or white in color.

Medical Author:
Medically Reviewed on 4/8/2019

Trichomoniasis Symptoms

About 70% of people who are infected do not show any symptoms. When people do have symptoms, they can range in severity from mild to severe. Symptoms develop anywhere from 5 to 28 days after being infected, but some people can develop symptoms even later. The symptoms may improve or even go away and then return in some people. If untreated, the infection can persist for months to years. The following are the typical symptoms in those who do develop symptoms of trichomoniasis:

Trichomoniasis Symptoms in Women

  • Smelly, itchy, and typically frothy or foamy vaginal discharge
  • Vaginal itching
  • Yellow or gray-green discharge
  • Pain with urination possible

Trichomoniasis Symptoms in Men

  • Urethral discharge
  • Pain with urination
  • Pain and swelling in the scrotum (from epididymitis)

Trichomoniasis Causes

Trichomoniasis is caused by Trichomonas vaginalis, a flagellated motile protozoan.

  • Approximately 174 million people worldwide are infected with this parasite each year, making it the most common curable sexually transmitted infection worldwide. In the U.S., it is estimated that about 3.7 million people have the infection. Only about 30% of these people will have any symptoms.
  • The average size of a trichomonad is 15 mm (they are not visible with the naked eye).
  • Reproduction of the parasites occurs every 8 to 12 hours.
  • Trichomonas vaginalis was isolated in 14% to 60% of male partners of infected women and in 67% to 100% of female partners of infected men. It is unclear why women are infected more often than men. One possibility is that prostatic fluid contains zinc and other substances that may be harmful to trichomonads.

STD Diagnosis, Images, Symptoms, Treatment Slideshow

STD Diagnosis, Images, Symptoms, Treatment Slideshow

It's not necessary to have sexual intercourse to get a sexually-transmitted disease (STD). The human papillomavirus (HPV) that causes genital warts can be transmitted by close skin-to-skin contact. Some types of HPVs cause cervical or anal cancer, and vaccines are available to protect against the most dangerous types. Other HPV types cause genital warts, which can be raised, flat, or cauliflower-shaped. HPV infection can occur in people who have no symptoms or visible warts.

HPV Symptoms

  • Genital warts can be big or small, flat or raised. They generally appear as a small bump or group of bumps in the genital region, and may be shaped like a cauliflower.

HPV Vaccine

  • A vaccine to prevent HPV is given in three shots. The second shot is given a month or two after the first shot. The third shot comes six months after the first shot.
  • The Centers for Disease Control recommends boys and girls be vaccinated at ages 11 or 12.
  • If they did not get the HPV vaccine as children, women can get the HPV vaccine through age 26. Men can get it through age 21. The CDC recommends HPV vaccination for men through age 26 for men who have sex with men or men with compromised immune systems, including HIV.


Kasper, D.L., et al., eds. Harrison's Principles of Internal Medicine, 19th Ed. United States: McGraw-Hill Education, 2015.