Trichomoniasis – Causes, Symptoms, Diagnosis, Treatment and Ongoing care
- Sexually transmitted urogenital infection caused by a pear-shaped, parasitic protozoan
- A cause of nongonococcal urethritis (NGU) in males
- System(s) affected: Genitourinary
- Synonym(s): Trich; Trichomonal urethritis
- Estimated 7.4 million new cases annually in the US in men and women
- 10–25% of vaginal infections
- 1–17% of cases of NGU; reported prevalence rates among men without urethritis have ranged from 0–8%.
- Predominant age: Young and middle-aged adults:
- Rare until onset of sexual activity
- Not uncommon in postmenopausal women; age is not protective, and long-term carriage is possible.
- Predominant sex: Male = Female, but women are more commonly symptomatic.
Rare in prepubertal children; confirmed diagnosis should raise concern of sexual abuse
- 2.3% of young adults:
- 2.8% of women
- 1.7% of men
- 3.1% of all US women
- Racial disparity exists (1):
- 1.3% of white, non-Hispanic women
- 1.8% of Mexican American women
- 13.3% of black, non-Hispanic women
- Multiple sexual partners
- Unprotected intercourse
- Lower socioeconomic status
- Other sexually transmitted infections (STIs)
- Untreated partner with previous infection
No known genetic considerations
- Use of male or female condoms
- Reducing exposure by limiting numbers of partners
- Male circumcision may be protective (2).
- Trichomonas vaginalis: A pear-shaped, flagellated, parasitic protozoan
- Grows best at 35–37°C in anaerobic conditions at pH of 5.5–6.0
- Sexually transmitted
- Transmission via a nonvenereal route is possible because the organism survives for several hours in a moist environment.
Commonly Associated Conditions
- Other sexually transmitted diseases, including HIV
- Bacterial vaginosis
- Yellow–green, malodorous vaginal discharge
- Vulvovaginal pruritus
- 50–75% are asymptomatic.
- Urethral discharge
- 80% are asymptomatic.
- Vaginal erythema
- Yellow–green, frothy, malodorous vaginal discharge
- Petechiae on cervix (strawberry cervix; seen in ∼10% of patients)
- Males: Penile discharge, spontaneous and with expression
Diagnostic Tests & Interpretation
Initial lab tests
- Wet mount of vaginal or urethral discharge (3)[A]: Direct visualization of motile trichomonads:
- Sensitivity of 60–70%
- Specificity of 99.8%
- Gram stain
- Detection on Pap smear (3)[A]:
- Sensitivity of 57–98%
- Specificity of 97%
- Culture: Sensitivity >95%; can take 4–7 days:
- Enzyme-linked immunosorbent assay and direct fluorescent antibody tests: Sensitivity 80–90%
- Rapid diagnostic kits using polymerase chain reaction DNA probes: Sensitivity 97%, specificity 98%
- Females (other vaginitides):
- Bacterial vaginosis
- Vaginal candidiasis
- Chlamydial infection
- Gonorrheal infection
- Mixed vaginitis
- Males (other urethritides):
- Chlamydial infection
- Gonorrheal infection
- Symptomatic individuals require treatment.
- Asymptomatic partners are also treated presumptively.
- Complete screening for other STIs should be considered part of required treatment.
- Metronidazole 2 g p.o., 1 dose (4)[A]
- Metronidazole 1.5 g p.o., 1 dose:
- Food and Drug Administration (FDA) pregnancy risk Category B
- American Association of Pediatrics recommends abstaining from breastfeeding during treatment and for 12–24 hours after last dose, but this is an old recommendation not supported by current evidence (5).
- Tinidazole 2 g p.o., 1 dose:
- FDA pregnancy risk Category C
- Abstain from breastfeeding during treatment and for 3 days after the dose.
- Only if still symptomatic after initial treatment
- Metronidazole 500 mg p.o. b.i.d. × 7 days (4)[A]
No evidence supports the use of metronidazole in asymptomatic patients because adverse outcomes are not prevented by treatment (6)[A].
If metronidazole resistance suspected, use tinidazole
Issues for Referral
- Multiresistant organism
- Patient allergy to metronidazole: Desensitization to metronidazole is possible.
- None currently available in the US
- Females (4)[A]:
- Clotrimazole 100 mg PV b.i.d. × 7 days
- Sulfanilamide-aminacrine-allantoin vaginal suppositories b.i.d. × 7 days
- Nonoxynol 9
- Povidone-iodine douche
Complementary and Alternative Medicine
None adequately investigated enough to be recommended
Admission may be necessary for resistant organisms because IV therapy provides higher tissue concentrations.
Clearance of infection
- If symptoms persist after initial treatment, reculture and/or repeat wet mount.
- No need for test of cure in asymptomatic individuals (4)[A].
Abstain from alcohol while being treated with 5-nitroimidazole derivatives due to disulfiramlike reaction.
Education about the sexually transmitted aspect of the infection:
- Inform partner so that partner can be treated.
- Discuss safe sex during health maintenance visits.
- Abstain from intercourse while undergoing treatment; use condoms if abstention is not feasible/possible.
- Avoid alcohol during treatment with metronidazole or tinidazole.
- Condom use can prevent recurrence.
- Usually treated after 1 course, but increasing number of metronidazole-resistant cases
Linked to low birth weight, preterm/premature rupture of membranes, preterm birth (6)
1. Sutton M, Sternberg M, Koumans EH, et al. The prevalence of Trichomonas vaginalis infection among reproductive-age women in the United States, 2001–2004. Clin Infect Dis. 2007;45:1319–26.
2. Sobngwi-Tambekou J, Taljaard D, Nieuwoudt M, et al. Male circumcision and Neisseria gonorrhoeae, Chlamydia trachomatis and Trichomonas vaginalis: observations after a randomised controlled trial for HIV prevention. Sex Transm Infect. 2009;85:116–20.
3. Wiese W, Patel SR, Patel SC, et al. A meta-analysis of the Papanicolaou smear and wet mount for the diagnosis of vaginal trichomoniasis. Am J Med. 2000;108:301–8.
4. Forna F, et al. Interventions for treating trichomoniasis in women. Cochrane Infectious Diseases Group. Cochrane Database Syst Rev. 2009;2.
5. Hale T. Medications and Mothers Milk: A Manual of Lactational Pharmacology (Medications and Mother’s Milk), 2009.
6. Gülmezoglu A. Interventions for trichomonas in pregnancy. Cochrane Pregnancy and Childbirth Group. Cochrane Database Syst Rev. 2010;1.
Allsworth JE, Ratner JA, Peipert JF, et al. Trichomoniasis and other sexually transmitted infections: results from the 2001–2004 National Health and Nutrition Examination Surveys. Sex Transm Dis. 2009;36:738–44.
Centers for Disease Control and Prevention, Workowski KA, Berman SM. Sexually transmitted diseases treatment guidelines, 2006. MMWR Recomm Rep. 2006;55:1–94.
Helms D, et al. Management of Trichomonas vaginalis in women with suspected metronidazole hypersensitivity. Am J Obstet Gynecol. 2008;198:370e1–370e7.
Klebanoff MA, Carey JC, Hauth JC, et al. Failure of metronidazole to prevent preterm delivery among pregnant women with asymptomatic Trichomonas vaginalis infection. N Engl J Med.2001;345:487–93.
McClelland RS, Sangare L, Hassan WM, et al. Infection with Trichomonas vaginalis increases the risk of HIV-1 acquisition. J Infect Dis. 2007;195:698–702.
Miller M, Liao Y, Gomez AM, et al. Factors associated with the prevalence and incidence of Trichomonas vaginalis infection among African American women in New York city who use drugs.J Infect Dis. 2008;197:503–9.
Saperstein AK, Firnhaber GC, et al. Clinical inquiries. Should you test or treat partners of patients with gonorrhea, chlamydia, or trichomoniasis? J Fam Pract. 2010;59:46–8.
Wendel KA, Workowski KA. Trichomoniasis: challenges to appropriate management. Clin Infect Dis. 2007;44(Suppl 3):S123–9.
- 131.00 Urogenital trichomoniasis, unspecified
- 131.01 Trichomonal vulvovaginitis
- 131.02 Trichomonal urethritis
- 131.03 Trichomonal prostatitis
- 131.09 Other urogenital trichomoniasis
- 131.8 Trichomoniasis of other specified sites
- 131.9 Trichomoniasis, unspecified
- 56335008 infection by Trichomonas (disorder)
- 35089004 urogenital infection by Trichomonas vaginalis (disorder)
- 81598001 trichomonal vulvovaginitis (disorder)
- 71590000 trichomonal prostatitis (disorder)
- 30116001 trichomonal urethritis (disorder)
- Both partners need to be treated for trichomoniasis.
- Test of cure is unnecessary.
- Avoid alcohol during treatment with standard agents.
- Treatment does not improve risk of adverse pregnancy outcomes.
- Male circumcision may be protective.