Trichomonas vaginitis is usually sexually transmitted.
It can cause a green or yellow discharge, which may be profuse, smell fishy, and be accompanied by itching or irritation.
If symptoms suggest a vaginal infection, doctors examine a sample of the discharge and/or fluid from the cervix and test it for microorganisms that can cause infection.
Always using a condom can help prevent this infection.
One dose of metronidazole or tinidazole taken by mouth cures most women.
(See also Overview of Vaginal Infections Overview of Vaginal Infections In the United States, vaginal infections are one of the most common reasons women see their doctor, accounting for millions of visits each year. Vaginal infections are caused by microorganisms... read more .)
The protozoa Trichomonas vaginalis can cause symptoms soon after they enter the vagina, or the protozoa can remain in the vagina or on the cervix (the lower part of the uterus that opens into the vagina) for weeks or months without causing any symptoms. The bladder may also be infected. In men, the protozoa usually cause no symptoms and may remain in the urinary tract for a few days or weeks without causing symptoms. Thus, women and men may be unaware that they are infecting their sex partners.
Causes of Trichomonas Vaginitis
Trichomonas genital infections (trichomoniasis Trichomoniasis Trichomoniasis is a sexually transmitted infection of the vagina or urethra that is caused by the protozoa Trichomonas vaginalis and that causes vaginal irritation and discharge and sometimes... read more ) are almost always sexually transmitted. Women can be infected through sexual contact with men or women. But men can be infected through sexual contact only with women, not with men. Many people who have this infection also have gonorrhea Gonorrhea Gonorrhea is a sexually transmitted infection caused by the bacteria Neisseria gonorrhoeae, which infect the lining of the urethra, cervix, rectum, and throat or the membranes that cover... read more 
or another sexually transmitted infections.
Because the protozoa can remain in women for a long time without causing symptoms, determining when the infection was acquired and thus from whom can be difficult or impossible.
Trichomoniasis may occur in children. If it does, the cause may be sexual abuse Sexual abuse Child maltreatment includes all types of abuse and neglect of a child under the age of 18 by a parent, caregiver, or another person in a custodial role (for example, clergy, coach, or teacher)... read more 
.
Symptoms of Trichomonas Vaginitis
Women with Trichomonas vaginitis may have a green or yellow vaginal discharge that is sometimes frothy, profuse, or both. It may smell fishy. The genital area may itch, and the vagina may be red and tender (irritated). As a result, sexual intercourse may be painful. Urination may also be painful if the bladder becomes infected.
The infection can lead to pelvic inflammatory disease Pelvic Inflammatory Disease (PID) Pelvic inflammatory disease is an infection of the upper female reproductive organs (the cervix, uterus, fallopian tubes, and ovaries). Pelvic inflammatory disease is usually transmitted during... read more 
and, in pregnant women, preterm labor Preterm Labor Labor that occurs before 37 weeks of pregnancy is considered preterm. Babies born prematurely can have serious health problems. The diagnosis of preterm labor is usually obvious. Measures such... read more and delivery.
Diagnosis of Trichomonas Vaginitis
A doctor's evaluation
Examination of a sample of the discharge and/or fluid from the cervix
If girls or women have a vaginal discharge that is unusual or that lasts for more than a few days or have other vaginal symptoms, they should see a doctor.
Doctors suspect Trichomonas vaginitis based on symptoms, such as a green or yellow frothy discharge. They then ask questions about the discharge, other symptoms, and possible causes (such as sexually transmitted infections).
To confirm the diagnosis, doctors do a pelvic examination Gynecologic Examination For gynecologic care, a woman should choose a health care practitioner with whom she can comfortably discuss sensitive topics, such as sex, birth control, pregnancy, and problems related to... read more . While examining the vagina, the doctor takes a sample of the discharge with a cotton-tipped swab. The sample is examined under a microscope. With information from this examination, the doctor can usually identify the microorganism causing the symptoms.
Usually, the doctor also uses a swab to take a sample of fluid from the cervix to test for other sexually transmitted infections.
If children have Trichomonas vaginitis, doctors evaluate them to determine whether sexual abuse could be the cause.
Prevention of Trichomonas Vaginitis
Always using a condom correctly during sexual intercourse can help prevent this infection from being transmitted. However, Trichomonas vaginalis protozoa can infect areas that are not covered by a condom. So condoms do not fully protect people from being infected.
Treatment of Trichomonas Vaginitis
Metronidazole or tinidazole
A single dose of metronidazole or tinidazole (antibiotics) taken by mouth cures up to 95% of women with Trichomonas vaginitis if sex partners are treated at the same time. So sex partners should be treated at the same time. People should not drink alcohol for at least 72 hours after they take metronidazole or tinidazole. Drinking alcohol while taking either drug can cause nausea, vomiting, cramps, flushing, and headaches.
During sexual intercourse, condoms should be used until the infection resolves to help prevent transmission of the infection.
