Trichomoniasis: Definition, Causes, Symptoms, Diagnosis, Treatment and Prevention

It is an infection caused by a single-celled protozoan called Trichomonas.

Usually confined to the vagina, this organism can invade the urinary tract and cause cystitis (inflammation of the bladder). The Trichomonas can also be severe enough to trigger an abnormal Pap smear.

From which, the organism can be detected and reappeared; although it can cause small red lesions on the cervix and fallopian tubes although they do not affect fertility.

We are talking about a sexually transmitted disease (STD). It is one of the most common STDs and can be called “trich.”

Symptoms include itching, irritation, and discharge in women, and painful urination in men. It is caused by a parasite, can be diagnosed with a physical exam and microscopic analysis, and can be treated with Flagyl ( metronidazole ), an antimicrobial.

Symptoms of trichomoniasis

Trichomoniasis symptoms can begin several days to a month after the person becomes infected, and there may even be a delay of several months before symptoms appear.

In fact, many people have no symptoms at all, but they can still pass the infection to other people. Women are more likely than men to experience symptoms if they become infected with trichomoniasis.

Symptoms in women

Symptoms in women are generally more noticeable than symptoms in men. Women generally experience trichomoniasis symptoms within 1 to 4 weeks of the initial infection.

Symptoms of trichomoniasis in women include:

  • Irritation and itching of the vagina and the surrounding area.
  • Foamy and colored vaginal discharge.
  • Strong vaginal odor.
  • Pain during sexual intercourse.
  • Pain when urinating
  • Trichomoniasis can also negatively affect the outcome of a pregnancy. Pregnant women infected with the parasite are more likely to deliver preterm and are more likely to give birth to a low-birth-weight baby.

Symptoms in men

Most men with trichomoniasis do not have any symptoms. When they do, their symptoms are generally mild and include:

  • Pain when urinating
  • Pain when ejaculating.
  • Discomfort in the penis.

Trichomoniasis and HIV

If you have trichomoniasis, you are more susceptible to infection with HIV, the virus that causes AIDS. If you are HIV positive, trichomoniasis also makes it more likely that you will pass HIV on to your sexual partners.

There is a stronger association between trichomoniasis and HIV in women than in men.


Trichomoniasis affects both men and women and is caused by a single-celled parasitic organism known as Trichomonas vaginalis.

The infection is transmitted sexually and can be spread through sexual intercourse, as well as skin-to-skin contact with the vagina or penis.

The parasite can live in and around the vagina or inside the penis and is not normally associated with the effects of other areas of the body. It is not spread by holding hands, touching or kissing it.

How it spreads

The CDC estimates that more than 3 million people in the United States are infected with trichomoniasis. The more common and frequent it is, the greater the chance of contracting the infection.

If you have unprotected sex with someone who might be infected, this makes you more likely to get the infection yourself.

Effects on the body

In women, trichomoniasis causes a vaginal infection called vaginitis. In men, it infects the urethra, the tube inside the penis that carries sperm and urine.

The parasite invades the layer under the skin and produces an inflammatory reaction. The presence of the parasite and the resulting inflammation produce the characteristic itching, pain, discharge, and odor associated with trichomoniasis.

Diagnosis of trichomoniasis

The symptoms of trichomoniasis are somewhat vague and similar to the symptoms of skin conditions or other sexually transmitted diseases. A doctor’s appointment is necessary for a definitive diagnosis, especially since there is a prescription deworming treatment that can cure the infection.

How the organism is identified

For both men and women, samples can be tested for the parasite, which can be viewed under a microscope.

A polymerase chain reaction (PCR) test, which can detect the genetic components of the parasite, can also be used to diagnose infection.

Diagnosis in women

If you have trichomoniasis, your physical exam may show vaginal irritation and discharge, and there may also be a distinctive odor.

Trichomoniasis can also cause irritation of the cervix, which is inside the body and can only be visualized with a medical exam.

A sample from the vagina, urethra (urine tube), or cervix provides a small sample of vaginal discharge. Your doctors can see this sample under a microscope.

This diagnostic method is done using a wet mount. It can be used to visualize the parasite itself.

However, the parasite that causes trichomoniasis is not always visible.

Your doctors can also cultivate vaginal secretions in a special medium to allow the organism to grow, which increases the chances of identifying it. A urine test can also be used for diagnosis.

Diagnosis in men

The physical exam is rarely abnormal in men who have a trichomoniasis infection. If you have symptoms of infection, your doctor may examine the infection with a urine sample or a urethral swab.


Treatment for trichomoniasis is generally effective if you are otherwise in good health. It is usually treated with a single oral dose of Flagyl (metronidazole) 2 grams or Tindamax (tinidazole) 2 grams.

If you received treatment and the infection did not resolve, you may need a prescription for metronidazole 500 mg by mouth to take twice a day for seven days. These drugs are also used to treat bacterial vaginosis.

There are cream and gel forms of metronidazole, but it is not effective for treating trichomoniasis.

You should not drink alcohol for several days when using these medications, as the combination can induce a serious physical reaction characterized by high blood pressure, shortness of breath, nausea, and vomiting.

After using the medications, it is recommended that you abstain from unprotected sexual activity for a week and until your symptoms disappear completely.

This is because it takes about a week for the medicine to get rid of the infection. It is also important that your sexual partners receive treatment for trichomoniasis while reducing the risk of reinfection.

Prevention of trichomoniasis

Condoms have been shown to reduce the risk of trichomoniasis infection. They should be used consistently if either partner is infected or may be at risk of infection.

The parasite can also be spread on fingers, sex toys, or other objects.