Published: 18 Jun 2025

ICD9: 131.9      ICD10: A59.9      ICD11: 1A92

Trichomoniasis (or "trich") is a very common sexually transmitted infection (STI) caused by a microscopic parasite called *Trichomonas vaginalis*.


Here's a breakdown:

Cause: The parasite *Trichomonas vaginalis*.

Transmission: Spread through sexual contact (vaginal, anal, or oral sex) with someone who has the infection. It primarily infects the vagina, urethra, or both in women, and the urethra in men.

Symptoms: Many people with trichomoniasis don't have any symptoms. When symptoms do occur, they can range from mild irritation to severe inflammation.

Women:
Frothy, yellow-green vaginal discharge with a strong odor.
Painful urination.
Vaginal itching, burning, or redness.
Discomfort during sexual intercourse.
Lower abdominal pain (rare).

Men:
Itching or irritation inside the penis.
Painful urination.
Discharge from the penis.

Diagnosis: A health care provider can diagnose trichomoniasis by examining a sample of vaginal fluid (in women) or urine (in men) under a microscope or through other lab tests.

Treatment: Trichomoniasis is curable with antibiotics, usually metronidazole or tinidazole. It's important for both partners to be treated to prevent reinfection.

Importance of Treatment: If left untreated, trichomoniasis can increase the risk of:

For Women:
Pelvic inflammatory disease (PID).
Premature labor and low birth weight babies.
Increased susceptibility to HIV infection if exposed.
Increased risk of cervical cancer.

For Men:
Increased risk of prostate cancer.
Increased risk of HIV infection if exposed.

Prevention: The best ways to prevent trichomoniasis are:

Abstaining from sexual activity.
Having a long-term mutually monogamous relationship with an uninfected partner.
Using condoms correctly every time you have sex.

Key Takeaways:

Trichomoniasis is a common and curable STI.
Many people don't have symptoms, so regular STI testing is important, especially for sexually active individuals.
If you think you might have trichomoniasis or any other STI, see a doctor or other healthcare provider for testing and treatment.