Trichomonas vaginitis (Trichomoniasis) - This type of vaginal infection is caused by a protozoan organism and is usually sexually transmitted. The discharge is typically yellow-green, frothy, and foul-smelling. The labia may appear swollen and red, and the vaginal walls may be red, rough, and covered with small red spots (or petechiae). This infection causes itching and urinary frequency in the client.