What is trichomoniasis?
Trichomoniasis is an infection with a tiny parasite spread by sexual contact (sexually transmitted infection [STI]). It is sometimes called a Trichomonas infection or trich (say "trick").
Both men and women can get a trich infection, but it is more commonly detected in women. Trich in pregnant women can cause problems with the pregnancy.
What causes trich?
Trich is caused by a one-cell parasite.
- In women, the parasite usually infects the vagina and cervix, urethra and bladder, and glands in the genital area.
- In men, the parasite infects the urethra or under the foreskin of the penis if it isn't circumcised.
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 women, symptoms include:
- Changes in your vaginal discharge. You may notice a colour or odour that isn't 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 can range from 5 to 28 days.footnote 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 examination. 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 pelvic examination.
How is it treated?
Your doctor will prescribe medicine called metronidazole to treat trich. It kills the parasite that causes the infection. The medicine is usually taken by mouth as pills, tablets, or capsules. Medicine given in the vagina will not cure trich.
It is important to treat trich. Treatment can:
- Kill the parasite and get rid of the infection and the 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 STIs, especially HIV.
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 STI.
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 isn't 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:
Trichomoniasis (trich) is caused by a tiny parasite (a one-celled protozoan) that most commonly is sexually transmitted from an infected person.
In men, infections develop in the urethra or under the foreskin of an uncircumcised penis.
Many women and men infected with trichomoniasis (trich) do not have symptoms. If symptoms develop, they usually appear within 1 week after a person is infected. But symptoms can develop months later.
Symptoms may be worse during pregnancy or right before or after a menstrual period. Symptoms in women may include:
- Large amounts of pale yellow or grey-green, sometimes foamy discharge from the vagina.
- Vaginal itching or irritation.
- Abnormal musty or fishy odour.
- Pain with sexual intercourse even if you use a lubricant such as K-Y Jelly or Astroglide.
- Patchy red areas on the genitals or on the cervix (strawberry cervix).
- Painful urination (dysuria) or frequent urination.
- Discomfort in the lower abdomen. This isn't a common symptom of trich, and it may mean another problem is present.
Men rarely have symptoms but still need treatment. If symptoms are present, they may include:
- Abnormal discharge from the penis.
- A burning feeling after urination.
- Irritation and redness of the tip of the penis.
Trichomoniasis (trich) infection is spread when you have unprotected sex with an infected partner. Many women and most men do not have any symptoms of trich. If symptoms appear, they usually start within 1 week after a person is infected. But it may take up to a month for symptoms to appear. In most cases, trich should be treated to prevent transmitting this sexually transmitted infection (STI) to others and to prevent some problems that can happen if you are pregnant. You and your sex partner(s) should be treated for trich at the same time, to avoid reinfecting each other.
Trich during pregnancy raises the risk of premature rupture of membranes (PROM) and premature delivery. Treating the infection may not always reduce this risk, but it can relieve symptoms and prevent infection in the newborn. If you are pregnant and have trich, talk to your doctor about the pros and cons of treatment.
Trich may be transmitted from a mother to her baby during a vaginal delivery, but this is rare.
What Increases Your Risk
Those most affected by trichomoniasis (trich) are sexually active women ages 16 to 35. It is thought that 1 out of 5 women in this age group will become infected at some time.footnote 2
Behaviours that will increase your risk of getting trich include:
- Not using condoms when having sex with a new partner or a partner who may have been exposed to a sexually transmitted infection (STI). It is possible for a partner to transmit the trich parasite without having any symptoms of the infection.
- Having many sex partners, which increases your risk of being exposed to someone who has trich. Teenagers and young adults are at higher risk for getting trich and other STIs, because their sex partners often have had other recent partners who may carry an STI.
You can get other STIs, such as gonorrhea, chlamydia, HIV, and syphilis, at the same time you get a trich infection. If one STI is diagnosed, testing for other STIs should be done so that all infections can be treated at the same time.
Some infections that can be spread through sexual contact, such as the human immunodeficiency virus (HIV) infection, are life-threatening. Studies show that trich infection may increase the risk of transmitting HIV infection.footnote 1 Health professionals around the world are concerned about the increased risk of trichomoniasis and HIV.
When To Call a Doctor
Call your doctor immediately if you:
- Have lower belly pain and a fever higher than 38.3°C (101°F) along with an abnormal vaginal discharge.
- Are pregnant and have symptoms of a vaginal infection or a urinary tract infection (UTI), such as abnormal discharge from the vagina or pain or burning during urination.
Call your doctor for an appointment within 1 week if you:
- Have an abnormal vaginal discharge.
- Have unusual vaginal itching.
- Have pain during sex or urination.
- Find out that your sex partner has been diagnosed with or treated for trichomoniasis (trich).
Watchful waiting is a period of time during which you and your doctor observe your symptoms or condition without using medical treatment. Watchful waiting isn't appropriate if you think you have trichomoniasis (trich). In most cases, trich should be treated to prevent transmitting this sexually transmitted infection to others and to prevent some problems that can happen if you are pregnant.
Note: Trich during pregnancy raises the risk of premature rupture of membranes (PROM) and premature delivery. Treating the infection may not always reduce this risk, but it can relieve symptoms and prevent infection in the newborn. If you are pregnant and have trich, talk to your doctor about the pros and cons of treatment.
Who to see
To prepare for your appointment, see the topic Making the Most of Your Appointment.
Examinations and Tests
Trichomoniasis (trich) is diagnosed by using:
- Your medical history, which will include questions about your sexual history and practices.
- A physical examination.
- For women, this will include a visual examination of the genitals, vagina, or cervix to detect patchy red spots that are caused by trich. Any vaginal discharge will be assessed for colour, odour, and texture. A sample of discharge is taken for a wet mount test.
- For men, this will include a visual examination of the penis and a sample of discharge from the urethra or a urine sample.
- Tests to identify the trich organism.
People can get other sexually transmitted infections (STIs), such as gonorrhea or syphilis, at the same time they get a trich infection. If one STI is diagnosed, you will likely be tested for other STIs so that all infections can be treated at the same time.
In women, the trich parasite may also be identified by a routine Pap test done as part of a regular gynecologic examination. Expert opinions vary on the accuracy of a Pap test for diagnosing trich. But if a Pap test shows trich, your doctor will probably talk to you about treatment or maybe other tests.
Trichomoniasis (trich) is treated with an oral antiprotozoal medicine, such as metronidazole. The medicine is taken either as a single dose or as multiple doses.
Your sex partner(s) should be treated at the same time you are being treated. This increases the cure rate and reduces the possibility of further transmission or reinfection. Sexual intercourse should be avoided during treatment until symptoms are gone and until partners have been treated. It is best to avoid sex for 1 week after treatment with a single dose of metronidazole. Male partners may not have symptoms but still need treatment.
People who are infected with HIV receive the same treatment for trich as those who are HIV-negative.
Trichomoniasis in pregnant women
Trichomoniasis during pregnancy raises the risk of premature rupture of membranes (PROM) and premature delivery. Treating the infection may not always reduce this risk, but it can relieve symptoms and prevent infection in the newborn. If you are pregnant and have trichomoniasis, talk to your doctor about the pros and cons of treatment.
Vaginal suppositories and creams aren't effective in curing trich, but they may reduce discomfort and swelling in the genital area.
- No follow-up is needed if symptoms go away. It is possible to get trich again, so it is important to take measures to reduce your risk for trich and other sexually transmitted infections (STIs).
- If symptoms do not go away, you may need to take the medicine again.
- If treatment fails after this and you have not been reinfected, further testing may be done to find out the cause of your symptoms. It is possible to have a strain of trich that is resistant to antiprotozoal medicines. If this is the case, you may need to take a large dose of metronidazole. This will usually cure the infection.footnote 1
Take measures to reduce your risk of becoming infected with trichomoniasis (trich) or other sexually transmitted infections (STIs), such as gonorrhea, chlamydia, HIV, or syphilis. You can also reduce the risk of transmitting an STI to your sex partner(s).
Practice safer sex
Preventing an STI is easier than treating an infection after it occurs.
- Talk with your partner about STIs before beginning a sexual relationship. Find out if he or she is at risk for an STI. Remember that it is quite possible to be infected with an STI without knowing it. It can take up to 6 months before some STIs, such as HIV, are detected in the blood.
- Be responsible.
- Avoid sexual contact if you have symptoms of an STI or are being treated for an STI.
- Avoid all intimate sexual contact with anyone who has symptoms of an STI.
- Don't have more than one sex partner at a time. Your risk of getting an STI increases if you have several sex partners at the same time.
Male condom use
Using condoms may reduce the risk of becoming infected with an STI. Condoms must be put on before beginning any sexual contact. Use condoms with a new partner until you are certain he or she does not have an STI. It is important that you use a condom properly to prevent the risk of trich infection.
Female condom use
Even if you are using a birth control method to prevent pregnancy, you may wish to use female condoms to reduce your risk of getting an STI.
There is no home treatment for trichomoniasis (trich). But you can lower your chances of getting trich or other sexually transmitted infections (STIs) by making careful choices about sex. For example, you can make sure to always use condoms during sex. For more information, see the topic Safer Sex.
Trich is not usually transmitted by contact with objects. But avoid using objects such as face cloths or wet towels that a person with trich may have used.
It is safe for a woman to use tampons while she has a trich infection, but it may be uncomfortable.
Avoid douching. It does not help relieve symptoms, and it can even make them worse.
Trichomoniasis (trich) is usually treated with a medicine called metronidazole.
Antiprotozoals, such as metronidazole, are medicines that kill the tiny parasite that causes trich.
What to think about
Metronidazole vaginal medicines aren't recommended because oral metronidazole works better.
Other Places To Get Help
- American Academy of Pediatrics (2015). Trichomonas vaginalis infections. In DW Kimberlin et al., eds., Red Book: 2015 Report of the Committee on Infectious Diseases, 30th ed., pp. 798–800. Elk Grove Village, IL: American Academy of Pediatrics.
- American Public Health Association (2008). Trichomoniasis. In DL Heymann, ed., Control of Communicable Diseases Manual, 19th ed., pp. 625–627. Washington, DC: American Public Health Association.
- Hobbs MM, et al. (2008). Trichomonas vaginalis and trichomoniasis. In KK Holmes et al., eds., Sexually Transmitted Diseases, 4th ed., pp. 771–793. New York: McGraw-Hill.
Other Works Consulted
- Expert Working Group on Canadian Guidelines for Sexually Transmitted Infections (2014). Canadian guidelines on sexually transmitted infections: Supplementary statement for recommendations related to the diagnosis, management, and follow-up of vaginal discharge. Public Health Agency of Canada. http://www.phac-aspc.gc.ca/std-mts/sti-its/cgsti-ldcits/disc-pert-eng.php. Accessed May 22, 2015.
- Grennan T (2016). Sexually transmitted infections. Compendium of Therapeutic Choices. Ottawa: Canadian Pharmacists Association. https://www.e-therapeutics.ca. Accessed August 1, 2016.
- McCormack WM, Augenbraun MH (2015). Vulvovaginitis and cervicitis. In JE Bennett et al., eds., Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases, 8th ed., vol. 1, pp. 1358–1371. Philadelphia: Saunders.
Primary Medical Reviewer Sarah Marshall, MD - Family Medicine
Brian D. O'Brien, MD - Internal Medicine
Kathleen Romito, MD - Family Medicine
Adam Husney, MD - Family Medicine
Martin J. Gabica, MD - Family Medicine
E. Gregory Thompson, MD - Internal Medicine
Specialist Medical Reviewer Jeanne Marrazzo, MD, MPH - Infectious Disease
Current as ofOctober 17, 2016
Current as of: October 17, 2016
Author: Healthwise Staff
Medical Review: Sarah Marshall, MD - Family Medicine & Brian D. O'Brien, MD - Internal Medicine & Kathleen Romito, MD - Family Medicine & Adam Husney, MD - Family Medicine & Martin J. Gabica, MD - Family Medicine & E. Gregory Thompson, MD - Internal Medicine & Jeanne Marrazzo, MD, MPH - Infectious Disease
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