What Is Trichomoniasis? Transmission, Symptoms and Treatment

Trichomoniasis is a common sexually transmitted infection (STI). In fact, it is the most common STI in the world. And it is one of the most common reasons for vaginal complaints. Anyone who is sexually active is at risk for an STI, like trichomonas. But this STI is unique in that it’s most often seen in older adults and those who are near menopause.

Trichomoniasis affects almost 4 million people in the U.S. Although, infection rates may be higher than that. That’s because only about 30% of people with the infection develop any symptoms.

What causes trichomoniasis (trich)?

The Trichomonas vaginalis parasite causes trich infection. It is an infection passed from one person to another during sexual contact. And in some cases, it can occur without penetration. It can spread from:

• Penis to vagina

• Vagina to penis

• Vagina to vagina (skin-to-skin contact)

• Penis or vagina to the throat with oral sex (rare)

Trichomoniasis infections can also spread with sex toys if they are not washed or if a condom isn’t used. But it does not seem spread very often through anal sex. 

The trichomonas parasite can live on moist surfaces outside the body for a few hours. And there have been rare cases of transmission of trichomoniasis from swimming pools, shared bath water, and towels. 

Symptoms of trichomoniasis

Symptoms can start within 1 to 4 weeks after an infection. But many people get no symptoms at all. If present, symptoms are more common in those with a vagina, than in those with a penis. 

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Symptoms if you have a vagina are:

• Itching, burning, redness, or soreness of the vagina

• Pain with urination

• Vaginal discharge (may be yellow, green, or gray)

• Vaginal odor described as “fishy”

• Pain during sex

Symptoms if you have a penis are:

• Discharge from the penis

• Itching or irritation in the penis

• Burning sensation with urination or after ejaculation

How is trichomoniasis diagnosed?

The diagnosis of trichomonas infection can occur in a few different ways. These include:

• Taking a sample from the vagina or cervix during a pelvic exam

• Taking a sample from the vagina with self-collection

• Taking a sample from the penis

• Taking a urine sample

Sometimes, your provider will examine vaginal samples in the office under a microscope. Samples are otherwise sent to a lab and checked for the presence of the Trichomonas vaginalis parasite.On a physical exam, there may be an abnormal discharge coming from the penis or from the vagina. It is also possible to see small red spots of vaginal irritation. These may be more clues for your provider that there is a trichomonas infection. 

What is the treatment for trichomoniasis?

The treatment for trichomoniasis is a course of antibiotics. Common antibiotics used to treat the infection include:

• Metronidazole

• Tinidazole

• Secnidazole

If you’re diagnosed with trichomoniasis, all your sexual contacts will need treatment as well. This is because if you get treated and your sexual contacts don’t, you could become infected again. 

Your healthcare provider will also recommend a period of abstinence from sex. This will be until everyone has completed their treatment and has no symptoms. This period will usually last for at least 7 days from the last dose of antibiotics for each partner.

What happens if trichomoniasis is left untreated?

Although there are often no symptoms, it is very important to treat trichomoniasis. If not treated, this infection can raise your risk of STIs. This includes infections like chlamydia, gonorrhea, and even HIV. Trichomoniasis infections can cause damage and inflammation in the genital tract. This makes it more likely for other germs to cause an infection. 

Along with raising the risk of other STIs, untreated trichomoniasis can also raise the risk of several other health problems. These problems include:

• Infertility

• Cervical cancer

• Epididymitis

• Prostatitis

If you have the infection while pregnant, you are more likely to have a preterm baby or a baby of low birth weight (less than 6 lbs). It can cause other problems after delivery as well. Although it is rare, trichomoniasis can spread from mother to child during childbirth. When this happens, it can cause vaginal and respiratory infections in newborns.

If you’re infected and continue to have unprotected sex, you could pass the infection on to others. An untreated trichomonas infection may be detected for years in vaginal fluid. But if you have a penis, sometimes the infection may clear on its own within 10 days, resulting in a negative test. This can make tracing the infection difficult in some cases.

How can I prevent the spread of trichomoniasis?

You can prevent the spread of trichomoniasis by lowering your risk of exposure from sex. Some ways you can lower your risk include:

• Practicing abstinence: The best way to prevent trichomoniasis or its spread is to not to have sexual contact at all. 

• Having one sexual partner: Infection and spread can be avoided if you have one sexual partner, are their only sexual partner, and both test negative.

• Using condoms: Condoms are an effective method to protect against trichomoniasis. Condoms should be used every time there is sexual contact. 

• Getting tested regularly: Talk with your healthcare provider about how often you should get screened.

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Written by:

Shola Ezeokoli, MD

Shola Ezeokoli, MD, is a board-certified internal medicine physician with 20 years of experience in healthcare. She is also a certified life coach, speaker, and writer with over 25 years of experience.

Edited by:

Karla Robinson, MD

Karla Robinson, MD, is a medical editor for GoodRx. She is a licensed, board-certified family physician with almost 20 years of experience in health through varied clinical, administrative, and educational roles.

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