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What is trichomoniasis?

Trichomoniasis is a sexually transmitted disease caused by infection with the protozoan Trichomonas vaginalis. In women this parasite infects the vagina; in men the epididymis, prostate or bladder can be involved. In the United States, the highest number of cases occur in women between ages 16 and 35. The disease is quickly and easily treated if diagnosed early, but left untreated it can lead to serious complications. Trichomonas infection is very common, with up to 7.4 million new cases occurring yearly in the United States (Source: CDC).

Symptoms of trichomoniasis vary among individuals. For example, some men exhibit no symptoms at all, particularly in the early stages of the disease. As the disorder progresses, or in men with early symptoms, urethral irritation, penile discharge, and burning with urination or ejaculation can occur. Left untreated, infection can spread to other organs, such as the prostate, and can also potentially contribute to male infertility.

In some women, symptoms may not appear for up to 28 days after infection, while in others symptoms arise almost immediately. Symptoms in women include painful intercourse and an unusual, strong-smelling vaginal discharge that is frothy and may be yellow-green in color.

Seek prompt medical care if you are being treated for trichomoniasis but mild symptoms recur or are persistent, if you are pregnant and have trichomoniasis, if you exhibit signs of bacterial infection such as frothy urine, anorectal pain, pain or burning with urination or ejaculation, pain during sexual intercourse in women, or discharge from the penis in men and abnormal vaginal discharge in women.

What are the symptoms of trichomoniasis?

The symptoms of trichomoniasis are largely confined to the genital areas and urinary tract in both men and women. In both men and women, it is possible to be infected with Trichomonas vaginalis and have no symptoms. Asymptomatic (symptom-free) trichomoniasis is particularly common in men.

Common symptoms of trichomoniasis in women

In women, trichomoniasis symptoms almost always consist of:

Common symptoms of trichomoniasis in men

Many men who have the infection exhibit no symptoms. As the disorder progresses, or in men who do exhibit symptoms, you can expect any combination of the following:

  • Burning with ejaculation
  • Itchy or irritated urethra (tube that carries urine from the bladder through the penis)
  • Pain or burning with urination
  • Urethral discharge

Symptoms that might indicate a serious condition

In some cases, trichomoniasis can co-occur with other sexually transmitted diseases that can be potentially serious. Seek immediate medical care (call 911) if you, or someone you are with, have any of these serious symptoms including:

What causes trichomoniasis?

Trichomoniasis is a sexually transmitted disease caused by infection with the protozoan Trichomonas vaginalis. It is spread through sexual contact, but the parasite does not survive in the mouth or rectum, nor does it survive for long on objects or surfaces. Women can get it from either men or women who are infected, but men usually get it from infected women. Also, in rare cases, a newborn can contract the disease from his or her mother.

If sexual partners are not treated at the same time, they can also end up passing the disease back and forth.

What are the risk factors for trichomoniasis?

Several factors increase the risk of developing trichomoniasis. Not all people with risk factors will get trichomoniasis. Risk factors for trichomoniasis include:

  • Bacterial vaginosis
  • Heritage of African descent
  • High vaginal pH levels
  • History of other sexually transmitted diseases
  • Lower socioeconomic status
  • Multiple sexual partners
  • Presence of another sexually transmitted disease
  • Unprotected sexual intercourse

Reducing your risk of trichomoniasis

You may be able to lower your risk of trichomoniasis by:

  • Abstaining from sex
  • Having sex only within a mutually monogamous relationship with an uninfected partner
  • Seeking regular medical care to be evaluated for trichomoniasis
  • Treating any current sexually transmitted diseases promptly
  • Using latex condoms (in most cases)

How is trichomoniasis treated?

Trichomoniasis is usually successfully treated with metronidazole (Flagyl), an antibiotic. Treatment may take several forms: the most effective are either a single-dose oral treatment or a series of smaller doses over one week. A newer drug called tinidazole (Tindamax) is also sometimes used in a single oral dose.

It is important that all sexual partners are treated at the same time, whether they all have symptoms or not, to avoid the spread of trichomoniasis. You and your partner should also abstain from sexual activity until the infection is cured completely. It is important to follow these rules of treatment and to take your full treatment.

What you can do to improve your trichomoniasis

In addition to carefully following instructions for your prescribed medication, you can also contribute to the improvement of your condition by:

  • Abstaining from sexual activity until the infection is cured completely
  • Treating all sexual partners at the same time, whether or not they have symptoms

What are the potential complications of trichomoniasis?

Complications of untreated or poorly controlled trichomoniasis can be serious and, in the case of ectopic pregnancy (life-threatening pregnancy growing outside the uterus), life threatening. In particular, women with trichomoniasis have an increased susceptibility to HIV infection. You can help minimize your risk of serious complications by following the treatment plan you and your health care professional design specifically for you. Complications of trichomoniasis include:

  • Fallopian tube inflammation in women
  • An increased risk for contracting HIV, which causes AIDS
  • Infertility
  • Permanent bladder tissue damage in men
  • Permanent cervical tissue damage in women
  • Possible low birth weight infant or premature delivery in pregnant women
  • Prostatitis
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Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2021 Jan 18
THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Never ignore professional medical advice in seeking treatment because of something you have read on the site. If you think you may have a medical emergency, immediately call your doctor or dial 911.
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  2. Trichomoniasis - CDC fact sheet. Centers for Disease Control and Prevention.
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  5. Tierney LM Jr., Saint S, Whooley MA (Eds.) Current Essentials of Medicine (4th ed.). New York: McGraw-Hill, 2011.