Trichomoniasis

Topic Overview

What is trichomoniasis?

Trichomoniasis is an infection with a one-cell parasite spread by sexual contact (sexually transmitted disease or STD). It is sometimes called a Trichomonas infection or trich (say "trick").

Both men and women can get a trich infection, but it is more common in women. Trich in pregnant women can cause problems with the pregnancy.

What causes trich?

Trich is caused by a one-cell parasite.

What are the symptoms?

Many women and most men do not have any symptoms of trich. But when you do have symptoms, they usually start within 1 week after you were infected. In some cases, it can take 1 to 6 months for symptoms to start.

In women, symptoms include:

  • Changes in your vaginal discharge. You may notice a color or odor that is not normal.
  • Vaginal itching.
  • Pain during urination or sex.

In men, symptoms include:

  • An abnormal discharge from the penis.
  • Irritation of the tip of the penis.
  • A burning feeling when you urinate.

The time from contact with the trich parasite until you get symptoms is usually 5 to 28 days.1 This is called the incubation period. You can spread trich to others during this time and until you finish the prescribed medicine. You should avoid all sexual contact until you finish taking your medicine and the symptoms are gone.

How is trich diagnosed?

Your doctor can tell if you have trich by asking about your past health and doing a physical exam. He or she may order lab tests to find the parasite that causes trich. In women, the parasite may sometimes be found during a routine Pap test. This test is done as part of a regular pelvic exam.

How is it treated?

Your doctor will prescribe medicine called metronidazole or tinidazole to treat trich. These kill the parasite that causes the infection. The medicine is usually taken by mouth as pills, tablets, or capsules. No medicine given in the vagina will cure trich.

It is important to treat trich. Treatment will:

  • Reduce your symptoms.
  • Prevent you from spreading trich to others. Make sure that your sex partner(s) will be treated at the same time that you get treatment so that you don't get infected again. Avoid all sexual contact until you finish taking the medicine and until your symptoms are gone.
  • Reduce the risk of pelvic infections. These may lead to women not being able to get pregnant (infertility). Trich can also lead to infertility in men.
  • Reduce the risk of infection after any pelvic surgery.
  • Reduce the risk of getting other STDs, especially HIV.

Trich during pregnancy raises the risk of premature rupture of membranes (PROM) and premature delivery. Treating the infection does not appear to reduce this risk.2 If you are pregnant and have trich, talk to your doctor about the pros and cons of treatment.

How is trich spread, and how can it be prevented?

Trich is spread when a person has unprotected sex with an infected partner. Some people carry the parasite that causes trich, but they do not have symptoms. So it is important to practice safe sex to prevent getting trich. Using a condom each time you have sex may reduce your chance of getting an STD.

In rare cases, it may be possible to get trich from contact with personal items, such as a wet towel, that a person with trich has just used. The trich parasite cannot live on objects for long, so it is not usually spread this way.

Trich may be spread from a mother to her baby during a vaginal delivery, but this is also rare.

Symptoms of a trich infection in young children may be a sign of sexual abuse. They need to be checked by a doctor.

Frequently Asked Questions

Learning about trichomoniasis:

Being diagnosed:

Getting treatment:

Ongoing concerns:


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Author: Amy Fackler, MA
Debby Golonka, MPH
Last Updated: August 10, 2006
Medical Review: Renée M. Crichlow, MD - Family Medicine
Kathleen Romito, MD - Family Medicine
Jeanne Marrazzo, MD, MPH - Infectious Disease

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