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.

• In women, the parasite usually infects the vagina, urethra, cervix, bladder, and glands in the genital area. See a picture of the female reproductive system .
• In men, the parasite infects the urethra or under the foreskin of the penis if it is not circumcised. See a picture of the male reproductive system .

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 can range from 4 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. 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 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

Cause

Trichomoniasis (trich) is caused by a tiny parasite (a one-celled protozoan) that most commonly is sexually transmitted from an infected person.

In women, trich organisms usually infect the vagina, urethra, cervix, bladder, and glands in the genital area, such as Bartholin's and Skene's glands. See a picture of the female reproductive system .

In men, infections develop in the urethra or under the foreskin of an uncircumcised penis. See a picture of the male reproductive system .

Symptoms

Up to 50% of women and men infected with trichomoniasis (trich) do not have symptoms.³ If symptoms develop, they usually appear within 1 week of being infected. But symptoms can develop months later.

In women

Symptoms may be worse during pregnancy or right before or after a menstrual period. If symptoms develop, they may include:

• Large amounts of pale yellow or gray-green, sometimes foamy discharge from the vagina.
• Vaginal itching or irritation.
• Abnormal musty or fishy odor.
• 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 is not a common symptom of trich and may mean another problem is present.

In men

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.

Trich can have symptoms similar to those of other sexually transmitted diseases such as gonorrhea or chlamydia.

What Happens

Trichomoniasis (trich) infection is spread by having 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 of being infected but can start from 1 to 6 months after being infected. In most cases, trich should be treated to prevent transmitting this STD 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.

In rare cases, it may be possible to get trich by coming in contact with an object (such as a wet towel) that a person who has trich has just used. The trich organism cannot live on objects for long, so trich is not usually spread this way.

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.

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

What Increases Your Risk

Sexually active women ages 16 to 35 are most affected by trichomoniasis (trich). It is thought that 1 in 5 women in this age group will become infected at some time.⁴

Behaviors 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 disease (STD). 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 STDs because their sex partners often have had other recent partners who may carry an STD.

You can get other STDs, such as gonorrhea, chlamydia, HIV, and syphilis, at the same time you get a trich infection. If one STD is diagnosed, testing for other STDs should be done so that all infections can be treated at the same time.

Some diseases 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.⁵ Health professionals around the world are concerned about the increased risk of trichomoniasis and HIV.

Women with trich may also be at risk for other vaginal infections. About 20% of women with trich also have a yeast infection and many also have bacterial vaginosis.⁶

When To Call a Doctor

Call your health professional immediately if you:

• Have lower abdominal pain and a fever higher than 101 °F (38.3 °C) along with an abnormal vaginal discharge.
• Are pregnant and have symptoms of a vaginal infection or a urinary tract infection (UTI).

Call your health professional 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

Watchful waiting is a period of time during which you and your health professional observe your symptoms or condition without using medical treatment. Watchful waiting is not appropriate if you think you have trichomoniasis (trich). In most cases, trich should be treated to prevent transmitting this sexually transmitted disease to others and to prevent some problems that can happen if you are pregnant.

Who To See

Health professionals who can diagnose and treat a trichomoniasis (trich) infection include:

• Physician assistants.
• Nurse practitioners.
• Family medicine doctors.
• Internists.
• Gynecologists.

To prepare for your appointment, see the topic Making the Most of Your Appointment.

Exams and Tests

Trichomoniasis (trich) is diagnosed by:

• Your medical history, which will include questions about your sexual history and practices.
• A physical examination.
  • For women, this will include a visual exam of the genitals, vagina, or cervix to detect patchy red spots that are caused by trich. Any vaginal discharge will be assessed for color, odor, and texture. A sample of discharge is taken for a wet mount test.
  • For men, this will include a visual exam of the penis and a sample of discharge from the urethra.
• Tests to identify the trich organism.
  • The most common test in women is a wet mount, a microscopic evaluation of fluid from the vagina. This test identifies trich 60% to 70% of the time.⁷
  • Other tests available but less commonly used include:
    • Culture. A culture identifies trich over 90% of the time and is especially useful for men.
    • Antigen detection test (immunochromatographic strip test) that detects trich over 83% of the time.⁸
    • DNA probe test, which detects genetic material (DNA) of the trich parasite.

People can get other sexually transmitted diseases (STDs) such as gonorrhea or syphilis at the same time they get a trich infection. If one STD is diagnosed, you will likely be tested for other STDs 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 exam. 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.

Treatment Overview

Trichomoniasis (trich) is treated with an oral antiprotozoal medicine, such as metronidazole or tinidazole. The medicine is taken either as a single dose (2 grams) or as multiple doses (250 to 500 mg) to equal a total of around 7 grams. The cure rate in treating trich using metronidazole is 90% to 95%. The cure rate using tinidazole is 86% to 100%.⁷

Sex partner(s) should be treated at the same time you are being treated to increase the cure rate and reduce the possibility of further transmission or reinfection. Sexual intercourse should be avoided during treatment until symptoms have gone away and until partners have been treated. Ideally, 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 does not appear to reduce this risk.² If you are pregnant and have trichomoniasis, talk to your doctor about the pros and cons of treatment.

Vaginal suppositories and creams are not effective in curing trich, but they may reduce discomfort and swelling in the genital area.

Follow-up

• 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 diseases (STDs).
• 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 determine the cause of your symptoms. It is possible to have a strain of trich that is resistant to antiprotozoal medicines. High-dose tinidazole may be used for metronidazole-resistant trich organisms and is as effective as metronidazole in curing trich.⁷

If trich goes untreated or is not properly treated, complications can develop, such as pelvic inflammatory disease (PID) in women or conditions that contribute to infertility in men.⁹

What To Think About

Metronidazole vaginal suppositories or creams are not recommended because oral metronidazole is much more effective. Vaginal medicines cure trich in less than 50% of cases.⁷

Metronidazole vaginal gel, which is used to treat bacterial vaginosis, is not recommended by the Centers for Disease Control and Prevention (CDC) for treatment of trich.⁷

Prevention

Take measures to reduce your risk of becoming infected with trichomoniasis (trich) or other sexually transmitted diseases (STDs), such as gonorrhea, chlamydia, HIV, or syphilis. You can also reduce the risk of transmitting an STD to your sex partner(s).

Practice safe sex

Preventing an STD is easier than treating an infection after it occurs.

• Talk with your partner about STDs before beginning a sexual relationship. Find out if he or she is at risk for an STD. Remember that it is quite possible to be infected with an STD without knowing it. It can take up to 6 months before some STDs, such as HIV, are detected in the blood.
• Be responsible.
  • Avoid sexual contact if you have symptoms of an STD or are being treated for an STD.
  • Avoid all intimate sexual contact with anyone who has symptoms of an STD.
• Don't have more than one sex partner at a time. Your risk of getting an STD increases if you have several sex partners at the same time.

Male condom use

Condom use may reduce the risk of becoming infected with an STD. 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 STD. Male or female condoms can be used. It is important that you use a condom properly to prevent the risk of trich infection. For more information, see how to use a condom.

Female condom use

Even if you are using a birth control method to prevent pregnancy, you may wish to use condoms to reduce your risk of getting an STD. Female condoms are available for women whose partners do not have or will not use a male condom. For more information, see how to use a female condom.

Home Treatment

There is no home treatment for trichomoniasis (trich). But you can lower your chances of getting trich or other sexually transmitted diseases (STDs) by making careful choices about sex. For example, you can make sure to always use condoms during sex. For more information, see the topic Safe Sex.

Trich is not usually transmitted by contact with objects, but it is important to avoid using objects such as washcloths 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.

Medications

Trichomoniasis (trich) is usually treated with a medicine called metronidazole. The cure rate in treating trich using metronidazole is 90% to 95%.⁷ Tinidazole has been shown to be this useful too.

Medication Choices

Antiprotozoals, such as metronidazole or tinidazole, are medicines that kill the tiny parasite that causes trich.

What To Think About

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.

Metronidazole vaginal suppositories or creams are not recommended because oral metronidazole is much more effective. Vaginal medicines cure trich in less than 50% of cases.⁷

Metronidazole vaginal gel, which is used to treat bacterial vaginosis, is not recommended for treatment of trich.⁷

Surgery

Surgery is not done to treat trichomoniasis.

Other Treatment

There is no other treatment for trichomoniasis at this time.

Other Places To Get Help

Organizations

Related Information

• Bacterial Vaginosis
• Chlamydia
• Exposure to Sexually Transmitted Diseases
• Gonorrhea
• Syphilis
• Vaginal Problems
• Vaginal Yeast Infections

References

Citations

1. American Academy of Pediatrics (2006). Trichomonas vaginalis infections (Trichomoniasis). In LK Pickering, et al., eds., American Academy of Pediatrics, 27th ed., pp. 673-674. Elk Grove Village, IL: American Academy of Pediatrics.

2. American College of Obstetricians and Gynecologists (2006). Vaginitis. ACOG Practice Bulletin No. 72. Obstetrics and Gynecology, 107(5): 1195-1206.

3. British Association of Sexual Health and HIV (2007). Management of Trichomonas Vaginalis Infection. Available online: http://www.bashh.org/guidelines.asp.

4. American Public Health Association (2004). Trichomoniasis. In DL Heymann, ed., Control of Communicable Diseases Manual, 18th ed., pp. 549-550. Washington, DC: American Public Health Association.

5. Forna F, Gülmezoglu AM (2003). Interventions for treating trichomoniasis in women. Cochrane Database of Systematic Reviews (2).

6. 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.

7. U.S. Department of Health and Human Services (2006). Sexually Transmitted Diseases Treatment Guidelines, 2006 (CDC Publication Vol. 55, No. RR-11), pp. 52-54. Atlanta: U.S. Department of Health and Human Services. Also available online: http://www.cdc.gov/STD/treatment/2006/rr5511.pdf.

8. Huppert JS, et al. (2005). Use of an immunochromatographic assay for rapid detection of Trichomonas vaginalis in vaginal specimens. Journal of Clinical Microbiology, 43(2): 684-687.

9. Soper D (2004). Trichomoniasis: Under control or undercontrolled? American Journal of Obstetrics and Gynecology, 190: 281-290.

Other Works Consulted

• American College of Obstetricians and Gynecologists (2006). Vaginitis. ACOG Practice Bulletin No. 72. Obstetrics and Gynecology, 107(5): 1195-1206.

• Anderson MR, et al. (2004). Evaluation of vaginal complaints. JAMA, 291(11): 1368-1379.

• McCormack WM (2005). Trichomoniasis section of Volvovaginitis and cervicitis. In GL Mandell et al., eds., Principles and Practices of Infectious Diseases, 6th ed., chap. 103, pp. 1361-1362. Philadelphia: Elsevier Churchill Livingstone.

• Schwebke, JR, Hook EW III (2003). High rates of trichomonas vaginalis among men attending a sexually transmitted diseases clinic: Implications for screening and urethritis management. Journal of Infectious Diseases, 188: 465-468.

Credits