The infection may coexist with gonorrhea and other STDs. In women, onset typically is accompanied by a copious, greenish yellow, frothy vaginal discharge associated with irritation and soreness of the vulva, perineum, and thighs and with dyspareunia and dysuria. Some women have only a slight discharge, and many are asymptomatic carriers for long periods, although symptoms may develop at any time. In severe cases, the vulva and perineum may be inflamed, with edema of the labia. The vaginal walls and surface of the cervix frequently are normal but may show punctate, red strawberry spots, or a small amount of discharge may be present in the vaginal fornices.
Men are generally asymptomatic.
Epididymitis and prostatitis are rare complications. In women, an immediate diagnosis can usually be made with an unstained saline suspension of vaginal secretion from the posterior fornix examined under ordinary light microscopy. The lashing movements of the flagella and striking motility of the oval-shaped organisms are readily observed. Cultures are more sensitive than direct examination. Trichomoniasis is also commonly diagnosed on a Papanicolaou smear.