Trichomoniasis: Symptoms, Treatment and Causes

Trichomoniasis: Symptoms, Treatment and Causes


Trichomoniasis is a sexually transmitted infection caused by a protozoan parasite and affects more than 8 million people in the US every year.

The infection is passed from partner to partner during sex. However, the incubation period for the infection is not entirely clear; incubation times are thought to range anywhere from 3-28 days after exposure to the parasite.


While trichomoniasis is highly curable, it can cause complications, especially in pregnant women. Woman infected during pregnancy are at risk for premature labor, low birthweight babies and infection transmission during birth.

In addition to pregnant women, the general population of women seems to be at a higher risk of contracting HIV when they have a trichomoniasis infection.

Fast facts on trichomoniasis

Here are some key points about trichomoniasis. More detail and supporting information is in the main article.

  • Trichomoniasis is a sexually transmitted infection often referred to as “trich”
  • Reinfection is common – around 1 in 5 people will be reinfected 3 months following completion of treatment
  • To prevent reinfection, patients and their sexual partners need to complete treatment
  • Vaginitis (inflammation of the vagina) is commonly caused by trichomoniasis
  • Only 30% of those infected with trichomoniasis develop symptoms
  • Trichomoniasis typically affects the vagina, vulva and urethra
  • Women affected with trichomoniasis during pregnancy are at a higher risk for premature labor.

Trichomoniasis, also referred to as “trich,” is a sexually transmitted infection caused by a microscopic, single-cell protozoan parasite called Trichomonas vaginalis. The parasite is spread from person to person via sexual intercourse.

In women, the area of the body that is affected by trichomoniasis most frequently is lower genital tract. In men, it is the urethra. The parasite does not typically infect other parts of the body such as the anus, hands or mouth.

According to the Centers for Disease Control and Prevention (CDC), trichomoniasis is the most common curable sexually transmitted disease (STD).

Risk factors for trichomoniasis

Those at an increased risk of being infected with trichomoniasis include:

  • Women, with older women more likely than younger women to become infected
  • People who have more than one sexual partner
  • People with a history of trichomoniasis or other sexually transmitted infections
  • People who have unprotected sex.

Symptoms of trichomoniasis

Up to 70% of people do not display any symptoms with a trichomoniasis infection. In particular, men with trichomoniasis are often asymptomatic.

When symptoms are present, trichomoniasis can affect men and women differently. These symptoms range in severity from minor cases of irritation to more extreme cases of inflammation involving discharge.

Symptoms of trichomoniasis for women include:

  • Frothy, foul-smelling vaginal discharge (clear, white, gray, yellow or green)
  • Blood in vaginal discharge
  • Genital irritation
  • Burning sensations in the genital region or during urination
  • Groin swelling
  • Painful intercourse (dyspareunia)
  • Urinary frequency
  • Painful urination (dysuria).

Symptoms of trichomoniasis for men include:

  • Urethral or penile discharge
  • Penile itching
  • Burning sensations after ejaculation or urination
  • Urinary frequency
  • Painful urination (dysuria).

trichomoniasis infection can increase the risk of an individual becoming infected with HIV, along with other sexually transmitted infections. This increased risk is attributed to the inflammation caused by trichomoniasis.

Trichomoniasis is linked to a number of complications for pregnant women:

  • Preterm birth
  • Premature membrane rupture
  • Low birth weight for babies (less than 5.5 pounds)
  • Potential transmission of infection to baby during birth.

Fortunately, trichomoniasis can be treated safely with antibioticsduring pregnancy.

Diagnosis of trichomoniasis

In order to diagnose a trichomoniasis infection, your health care provider will need to take a sample of vaginal or penile discharge or urine. They can either examine the sample under a microscope or send it to a laboratory for additional testing.

There are a number of steps that women can take to make the process of diagnosis easier for health care practitioners:

  • Do not douche for at least 24 hours before an appointment as this washes away discharge
  • Avoid using deodorant on the vulva – this masks smells and can cause irritation
  • Do not have vaginal intercourse or insert any object (including tampons) into the vagina for 24-48 hours prior to an appointment
  • If possible, schedule an appointment for when you are not on your period.

Previously, trichomoniasis would be diagnosed by growing a culture from a sample. Nowadays, diagnosis is much quicker, with health care providers able to utilize quicker tests such as rapid antigen tests and nucleic acid amplification.

Treatment for trichomoniasis

Trichomoniasis is easily treated in men and women, including those who are pregnant. Most commonly, treatment consists of a single dose of either metronidazole (Flagyl) or tinidazole (Tindamax), forms of antibiotic medication that kill parasites. This medication comes in pill form and is taken orally.

It is important that you and your sexual partners are treated following a diagnosis of trichomoniasis. You should also avoid having sex for a week following treatment. These measures help prevent reinfection.1-3

You can prevent infection with trichomoniasis by using condoms or practicing abstinence.

If you think you have been exposed to trichomoniasis or think that you have the symptoms of an infection, speak with your health care provider for evaluation and treatment.

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