What Is Trichomoniasis?

Trichomoniasis is a parasitic sexually-transmitted infection (STI) that can affect people of any gender. The infection affects 2.1% of people assigned female at birth and 0.5% of people assigned male at birth. Millions of trichomoniasis cases have occurred in the United States.

Though it is common, trichomoniasis can present with no symptoms. However, signs of trichomoniasis may show up days after a person has been infected. Signs such as unusual discharge or irritation around the genitals can indicate a trichomoniasis infection.

For all individuals, trichomoniasis is diagnosed with different tests during a physical exam, which can include cultures and samples for microscopic review.

Antibiotics can help eliminate symptoms of those affected, and treatment must involve partners too to reduce the chance of getting the infection again. You can prevent the transmission of trichomoniasis by, for example, not engaging in sexual activity until symptoms have been resolved.

People can have trichomoniasis along with other STIs like chlamydia or gonorrhea, and it’s common for the infection to happen more than once after treatment. Though it is also one of the most prevalent STIs, it's also among the few that are curable.

Trichomoniasis Symptoms

Trichomoniasis, also known as “trich,” can present with no symptoms. In fact, around 70% of people with the infection do not show any signs.

If symptoms do occur, they may appear between five to 28 days after infection. A person may experience:

• Itchiness or irritation in and around the genital area
• Discomfort during sexual activity or when urinating
• Severe inflammation
• Vaginal discharge with a thin or frothy consistency and a foul odor. The discharge may be clear, white, gray, yellowish, or greenish.
• Penile discharge
• Red spots around genital area
• Pain in different areas, like the abdominal area, the testes, or the pelvis.

Trichomoniasis symptoms may disappear and return.

What Causes Trichomoniasis?

Trichomoniasis is caused by a parasitic organism called Trichomonas vaginalis. It is close to the size of a white blood cell, and Trichomonas vaginalis can live for hours in moist environments. The parasite can be found in the genitourinary tract of people assigned female at birth and the prostate and urethra of people assigned male at birth.

Risk Factors

A person may be at risk for spreading or getting trichomoniasis if they:

• Have a history of STIs
• Have a new sexual partner or multiple partners
• Come into sexual contact with a person who has trichomoniasis
• Misuse drugs that are administered intravenously (in the vein)
• Do not use barrier contraception (e.g., condoms)

Research has also suggested that other risk factors for trichomoniasis include having less than a high school diploma, living below the Federal Poverty Line, and smoking.

How Is Trichomoniasis Diagnosed?

If you think or know you have symptoms of trichomoniasis, you — and any partners you have engaged in sexual activity with — should seek medical attention.

When getting information about your medical history to confirm a trichomoniasis diagnosis, healthcare providers may ask about previous STI treatments and condom use. They might also use one of the following tests or methods:

• Nucleic acid amplification test (NAAT): This FDA-approved test, used for people assigned female at birth, is designed to test for Trichonomas vaginalis.
• Cotton swab sample: Healthcare providers may take a sample of discharge or cells as part of a physical exam, and a lab professional will observe the sample under a microscope to look for evidence of parasites.
• Urine sample: A provider may also ask you to provide a urine sample during a physical exam for analysis.

Microscopic exams are 40 to 60% sensitive when testing for Trichonomas vaginalis. However, NAATs have 90% sensitivity when testing for the parasite. Additionally, a NAAT can be used to confirm that the STI has been cured.

Additional testing will likely be included in order to rule out the presence of any other STIs. Also, a Pap test can also provide evidence of trichomoniasis, but it’s not used as part of the diagnostic process.

Treatments for Trichomoniasis

Providers who may play a role in your treatment plan can include a primary care physician, an infectious disease expert, and a gynecologist. Also, individuals and their partners should be treated if anyone has been diagnosed with trichomoniasis.

Treatment of trichomoniasis involves the use of oral antibiotics. There are two oral antibiotics available for treatment: metronidazole and tinidazole.

Depending on a person’s sex, treatment can vary. People assigned female at birth are prescribed 500 milligrams of metronidazole two times per day for seven days or 2 grams of tinidazole in one dose. People assigned male at birth are prescribed 2 grams of either antibiotic in one dose.

It is specifically recommended that pregnant individuals be treated due to potential outcomes such as an increased risk of delivering a baby early or the baby having a low birth weight. Of note, tinidazole is not prescribed for those who are pregnant, while metronidazole is contraindicated before the second trimester.

How to Prevent Trichomoniasis

Refraining from vaginal, anal, or oral sex can prevent trichomoniasis. Having sex with only one partner who has been tested for STIs and does not have trichomoniasis (or any STIs) can also reduce your risk of developing the STI. Another important action is making sure that you are using any condoms the right way to further reduce risk.

Comorbid Conditions

Trichomoniasis increases a person’s risk of developing additional STIs. As a result, trichomoniasis has comorbidity with other STIs. Possible comorbid STIs include ones such as:

• Chlamydia: The most common bacterial STI that often does not have symptoms
• Gonorrhea: The second most common bacterial STI 
• Herpes: A viral STI that affects the genitals
• Human immunodeficiency virus (HIV): A viral STI that attacks the immune system
• Human papillomavirus (HPV): A viral STI transmitted through genital or skin contact

Living With Trichomoniasis

Individuals can become infected with trichomoniasis again if they are sexually active. This recurring infection can happen to one in five people within three months following treatment.

People could potentially develop pelvic inflammatory disease (PID) — inflammation that can affect the uterus, Fallopian tubes, and ovaries — due to a trichomoniasis infections. Also, for individuals assigned male at birth, complications from trichomoniasis can include:

• Epididymitis (a condition where a person has an inflamed epididymis, the tube at the back of the testicle)
• Prostatitis (a prostate gland disorder)
• Infertility

Cases of trichomoniasis can be cured, however, as it is one of the four most common curable STIs. Cure rates are high for people who have used metronidazole as a treatment option and even higher when partners who have the STI are treated too.

Just remember to talk with potential partners about any possible STI risks and consult with a healthcare provider to determine if and when you need to get tested for STIs.