Trichomoniasis causes symptoms like unusual vaginal discharge, genital itching, and burning during urination, though many people with the infection notice nothing at all. It’s one of the most common sexually transmitted infections worldwide, caused by a microscopic parasite called Trichomonas vaginalis that spreads through sexual contact. The tricky part is that symptoms can take anywhere from 5 to 28 days to appear after exposure, and they look different depending on your sex.
Symptoms in Women
The hallmark symptom is a profuse, yellow-green, frothy vaginal discharge with a strong, unpleasant odor. That combination of color, texture, and smell is fairly distinctive. Women with trichomoniasis are about 2.4 times more likely to report yellow discharge and 3 times more likely to experience vulvar itching compared to women with other vaginal infections.
Beyond discharge, common symptoms include burning or stinging during urination, soreness and redness around the vulva and inside the vagina, and discomfort during sex. Some women also notice general irritation or swelling in the genital area. During a pelvic exam, a clinician may spot what’s called a “strawberry cervix,” tiny red spots on the cervix caused by inflammation and small areas of bleeding. This sign is strongly associated with trichomoniasis and is rarely seen with other infections.
Symptoms can shift throughout the menstrual cycle. Research shows that the number of parasites in the vagina actually drops during menstruation, then rebounds within three to six days after bleeding stops. This means symptoms may temporarily ease during a period and flare up again afterward.
Symptoms in Men
Men tend to have milder or fewer noticeable symptoms. When symptoms do appear, they typically include itching or irritation inside the penis, burning after urination or ejaculation, and a thin discharge from the penis. These symptoms overlap heavily with other urethral infections, which is one reason trichomoniasis in men often goes undiagnosed.
Men are also more likely than women to clear the infection on their own without treatment, which further complicates detection. But even without symptoms, an infected person can still pass the parasite to sexual partners.
Many Infections Are Silent
A large proportion of people with trichomoniasis never develop symptoms. The infection can persist quietly for weeks, months, or even longer. Global data from 2021 estimated an incidence rate of roughly 4,100 cases per 100,000 people, yet the health burden falls disproportionately on women. While infection rates are similar between men and women, the disability and complications caused by trichomoniasis are roughly 28 times higher in women. That gap exists largely because asymptomatic infections in women can silently cause ongoing inflammation and lead to complications.
How It Differs From BV and Yeast Infections
Vaginal discharge is a symptom of several common conditions, so it helps to know how they compare. Bacterial vaginosis (BV) produces a thin, off-white discharge with a fishy odor but generally doesn’t cause much redness or irritation. A yeast infection typically shows up as thick, white, cottage cheese-like discharge with intense itching but little odor. Trichomoniasis sits apart with its yellow-green, frothy discharge, strong smell, and visible inflammation or redness of the vulva and vagina.
That said, these categories aren’t always neat. Some women have more than one infection at once, and mild cases of trichomoniasis can look a lot like BV. Testing is the only reliable way to tell them apart.
Risks During Pregnancy
Trichomoniasis during pregnancy raises the stakes. A large meta-analysis found that infected pregnant women are about 27% more likely to deliver preterm (before 37 weeks) compared to uninfected women. The risk of having a baby with low birth weight (under about 5.5 pounds) roughly doubles. The odds of membranes rupturing before labor begins are nearly twice as high as well. These aren’t dramatic increases in absolute terms for any one pregnancy, but they’re consistent enough across studies that screening and treatment during pregnancy matter.
What Treatment Looks Like
Trichomoniasis is curable with a course of oral antibiotics. Symptoms typically start improving within a few days of starting treatment. Both partners need to be treated at the same time to prevent passing the infection back and forth, and you should avoid sex until treatment is complete and symptoms have fully resolved. Reinfection is common, so follow-up testing about three months after treatment is generally recommended.
Left untreated, the infection doesn’t just linger. It increases vulnerability to other sexually transmitted infections and keeps the genital tissue in a state of chronic, low-grade inflammation that can cause ongoing discomfort even when obvious symptoms aren’t present.