Trichomoniasis
Trichomoniasis - Summary
Trichomonas vaginalis is a protozoal parasite that is sexually transmitted.
In 2007, a new diagnosis of trichomoniasis was made in 5592 women and 437 men by sexual health clinics in the UK.
There is evidence that trichomoniasis is associated with perinatal complications (preterm delivery and low birthweight) in pregnant women.
Up to half of infected women have no symptoms. The most common symptoms include vaginal discharge, vulval itching, dysuria, and offensive odour. Inflammation of the vulva and vagina, or cervix may be seen.
Of men with trichomoniasis, 15–50% are asymptomatic and usually present as sexual partners of infected women. The most common presenting symptoms are urethral discharge and/or dysuria. Other clinical features include balanitis, urethral irritation, and increased urinary frequency.
The diagnosis of trichomoniasis should ideally be confirmed by a sexual health specialist (i.e. a sexual health clinic or a general practice providing an enhanced sexual health service). If referral is not possible the person can be tested in primary care, but the results may not be as reliable.
For women, a high vaginal swab (from the posterior fornix) should be sent for laboratory testing.
For men, a urethral swab should be sent for laboratory testing.
Treatment for confirmed trichomoniasis should ideally be commenced by a sexual health specialist. If this is not possible the person should be managed in primary care. Management of trichomoniasis includes:
Providing information on trichomoniasis.
Advising sexual abstinence until treatment is completed and any partners have also been treated and followed up.
Giving advice on the importance of safer sexual practices in reducing the risk of further infection and exposure to other STIs.
Screening for coexisting STIs and advising on contact tracing.
Antibiotic treatment.
For non-pregnant symptomatic women, metronidazole should be prescribed. If metronidazole is not tolerated tinidazole should be offered.
For pregnant symptomatic women, a course of metronidazole should be prescribed. If metronidazole treatment is declined clotrimazole pessaries should be offered.
For pregnant asymptomatic women, treatment options should be discussed with their obstetrician or a sexual health specialist.
For men, metronidazole should be prescribed. If metronidazole is not tolerated tinidazole should be offered.
After completion of treatment, the person should be followed up to review symptoms, confirm that contact tracing has been carried out, and discuss the results of the STI screen.
Test to confirm cure should not be routinely done. Repeat testing for trichomoniasis is only recommended if symptoms persist after treatment or recur after treatment is completed.
Have I got the right topic?
This CKS topic covers the diagnosis and management of trichomoniasis in men and women (including pregnant women).
This CKS topic does not cover the management of other sexually transmitted infections.
There are separate CKS topics on Bacterial vaginosis, Candida - female genital, Chlamydia - uncomplicated genital, Pelvic inflammatory disease, Pruritus vulvae, and Vaginal discharge.
The target audience for this CKS topic is healthcare professionals working within the NHS in the UK, and providing first contact or primary health care.
How up-to-date is this topic?
How up-to-date is this topic?
Changes
August 2009 — minor update. Advice from the National Institute for Health and Clinical Excellence guideline on when to suspect child maltreatment has been added to this topic [NICE, 2009]. Issued in August 2009.
February to June 2009 — converted from CKS guidance to CKS topic structure. The evidence-base has been reviewed in detail, and recommendations are more clearly justified and transparently linked to the supporting evidence.
There are no major changes to the recommendations.
Previous changes
January 2008 — minor update. Text changed in line with the National Guideline on the Management of Trichomonas vaginalis (2007) from the British Association for Sexual Health and HIV. Issued in February 2008.
October–December 2005 — reviewed. Validated in March 2006 and issued in May 2006.
March 2002 — reviewed. Validated in June 2002 and issued in July 2002.
June 1999 — rewritten, replacing previous guidance called Trichomonas vaginalis infection. Validated in October 1999 and issued in January 2000.
Update
New evidence
Evidence-based guidelines
Guidelines published since the last revision of this topic:
BASHH (2010) United Kingdom national guideline on the management of sexually transmitted infection and related conditions in children and young people - 2010. British Association for Sexual Health and HIV. www.bashh.org [Free Full-text (pdf)]
FSRH and BASHH (2012) Management of vaginal discharge in non-genitourinary medicine settings. Faculty of Sexual and Reproductive Healthcare. www.fsrh.org.uk [Free Full-text (pdf)]
HTAs (Health Technology Assessments)
No new HTAs since 1 January 2009.
Economic appraisals
No new economic appraisals relevant to England since 1 January 2009.
Systematic reviews and meta-analyses
No new systematic review or meta-analysis since 1 January 2009.
Primary evidence
No new randomized controlled trials published in the major journals since 1 January 2009.
A prospective clinical comparative study has been published since the last revision of this topic:
Lowe, N.K., Neal, J.L., and Ryan-Wenger, N.A. (2009) Accuracy of the clinical diagnosis of vaginitis compared with a DNA probe laboratory standard. Obstetrics and Gynecology 113(1), 89-95. [Abstract] [Free Full-text]
New policies
No new national policies or guidelines since 1 January 2009.
New safety alerts
No new safety alerts since 1 January 2009.
Changes in product availability
No changes in product availability since 1 January 2009.
Goals and outcome measures
Goals
Early recognition of symptoms suggestive of trichomoniasis
Appropriate referral to secondary care or other specialist service if possible
Appropriate management in primary care if specialist referral is not possible
Making an accurate diagnosis
Screening for other sexually transmitted infections
Appropriate treatment in primary care settings
Ensuring contact tracing
Providing appropriate advice to patients
Background information
Definition
What is it?
Trichomonas vaginalis is a protozoal parasite that is sexually transmitted [Mabey et al, 2006].
Prevalence
How common is it?
Trichomoniasis accounts for about 2% of genitourinary medicine (GUM) clinic attendances [HPA, 2002].
In 2007, a new diagnosis of trichomoniasis was made in 5592 women and 437 men by GUM clinics in the UK [HPA, 2008].
From 2000–2007, the number of women diagnosed with trichomoniasis in GUM clinics in the UK remained fairly constant, but the number of men diagnosed decreased [HPA, 2008].
Complications
What are the complications?
There is evidence that trichomoniasis is associated with perinatal complications (preterm delivery and low birthweight) in pregnant women [Nanda et al, 2006].
Diagnosis
Diagnosis
Diagnosis - men
Diagnosis of trichomoniasis in men
Clinical features
What are the clinical features of trichomoniasis in men?
Of men with trichomoniasis, 15–50% are asymptomatic and usually present as sexual partners of infected women.
The most common presenting symptoms are urethral discharge or dysuria, or both.
Urethral discharge is present in 50–60% of men (usually only small or moderate amounts).
Rarely, the discharge can be copious.
Other clinical features include:
Balanitis.
Urethral irritation.
Increased urinary frequency.
Occasionally, men can present with prostatitis.
For more information, see the CKS topics on Balanitis, Prostatitis - acute, Prostatitis - chronic, and Urethritis - male.
Basis for recommendation
Basis for recommendation
This information is from guidelines developed by the British Association of Sexual Health and HIV and is based on expert opinion [BASHH, 2004; BASHH, 2007].
Diagnosis
How should I make a diagnosis of trichomoniasis in men?
Ideally, refer the man to a service specializing in sexual health or a general practice providing an enhanced sexual health service for diagnosis and treatment. If this is not possible it is reasonable to test him in primary care, but the results may not be as reliable.
In men with urethral symptoms, ensure that infection with Neisseria gonorrhoeae, Chlamydia trachomatis, and Mycoplasma genitalium has been excluded or treated. For more information, see the CKS topic on Urethritis - male.
For trichomoniasis, send a urethral swab for laboratory testing (usually microscopy) and state on the form that trichomoniasis is suspected.
The swab should be stored in transport medium (such as Amie's or Stuart's), should be refrigerated before transportation, and ideally should arrive at the laboratory within 6 hours.
Some laboratories may accept a first-void urine specimen, but it is advisable to check with local services first.
If the test is positive for trichomoniasis, or the man's partner has trichomoniasis, offer treatment. If the test is negative, refer the man to a service specializing in sexual health.
Laboratory testing
Laboratory testing
The motility of Trichomonas vaginalis diminishes with time, therefore swabs should arrive at the laboratory within 6 hours [BASHH, 2004; RCGP and BASHH, 2006; BASHH, 2007].
Diagnosing trichomoniasis in men is much more difficult than in women [Nanda et al, 2006].
Direct observation by wet-mount or staining will diagnose about 30% of infections in men [RCGP and BASHH, 2006].
Diagnosis by culture is considered to be the gold standard and increases the detection rate, but requires specific culture media, takes longer than microscopy, and is not routinely done by most laboratories [BASHH, 2006; Mabey et al, 2006; RCGP and BASHH, 2006; BASHH, 2007].
Urethral culture if a discharge is present, or culture of first-void urine, will diagnose 60–80% of infected men. Testing both samples increases the diagnostic rate [Nanda et al, 2006; BASHH, 2007].
Polymerase chain reaction tests are more sensitive and specific when compared with microscopy or culture, but are not currently in general use [Schwebke and Lawing, 2002; BASHH, 2007].
Basis for recommendation
Basis for recommendation
These recommendations are from guidelines developed by the British Association of Sexual Health and HIV and the Royal College of General Practitioners and are based on expert opinion [BASHH, 2004; BASHH, 2006; RCGP and BASHH, 2006] and an observational study [BASHH, 2007].
Referral to a service specializing in sexual health
Referral to a service specializing in sexual health or a general practice providing an enhanced sexual health service is advised to confirm the diagnosis by microscopy of a wet-mount preparation in which characteristic motile, flagellated protozoa can be seen [Mabey et al, 2006].
Testing in primary care is often impractical (for example, due to a lack of immediate access to microscopy) and reduces the chance of detecting trichomoniasis compared with a setting where microscopy is available on-site.
Diagnosis - women
Diagnosis of trichomoniasis in women
Clinical features
What are the clinical features of trichomoniasis in women?
Up to half of infected women have no symptoms.
The most common symptoms include vaginal discharge, vulval itching, dysuria, and offensive odour. Vulvovaginal soreness and dyspareunia may also be presenting features.
No abnormalities are found on examination in 5–15% of infected women.
Vaginal discharge is present in up to 70% of infected women.
The discharge varies in consistency from thin and scanty to profuse and thick.
The classic discharge is frothy and yellow–green, and occurs in 10–30% of women.
For other causes of vaginal discharge, see the CKS topic on Vaginal discharge.
Inflammation of the vulva and vagina, or more rarely a strawberry appearance of the cervix, may be seen.
Basis for recommendation
Basis for recommendation
This information is from guidelines developed by the British Association of Sexual Health and HIV and is based on expert opinion [BASHH, 2004; BASHH, 2007].
Diagnosis
How should I make a diagnosis of trichomoniasis in women?
Ideally, refer the woman to a service specializing in sexual health or a general practice providing an enhanced sexual health service to confirm the diagnosis if trichomoniasis is suspected.
If referral is not possible, confirm the diagnosis by sending a high vaginal swab (from the posterior fornix) for laboratory testing.
The swab should be stored in transport medium (such as Amie's or Stuart's), should be refrigerated before transportation, and ideally should arrive at the laboratory within 6 hours.
If trichomoniasis is detected incidentally on cervical cytology or by microscopy of a urine sample, and attendance at a specialist sexual health service is not possible, send a high vaginal swab to the laboratory to confirm the diagnosis, as the specificity and sensitivity of cytology is poor.
Laboratory testing
The motility of Trichomonas vaginalis diminishes with time, therefore swabs should arrive at the laboratory within 6 hours [BASHH, 2004; RCGP and BASHH, 2006; BASHH, 2007].
Sensitivity of testing varies depending on the test done. In women, wet-mount has a sensitivity of 40–80%, whereas culture has a sensitivity of up to 95% [RCGP and BASHH, 2006].
Diagnosis by culture is considered to be the gold standard and increases the detection rate, but requires specific culture media, takes longer than microscopy, and is not routinely carried out by most laboratories [BASHH, 2006; Mabey et al, 2006; Nanda et al, 2006; RCGP and BASHH, 2006; BASHH, 2007].
Polymerase chain reaction tests are more sensitive and specific when compared with microscopy or culture, but are not currently in general use [Schwebke and Lawing, 2002; BASHH, 2007].
Cervical cytology may detect Trichomonas vaginalis as an incidental finding, with a weighted mean sensitivity of 58%. However, the false-positive rate is around 30% with pap smears, and may be less with liquid-based cytology, so diagnosis should be confirmed by microscopic examination or culture of vaginal secretions [BASHH, 2007].
Basis for recommendation
Basis for recommendation
These recommendations are from guidelines developed by the British Association of Sexual Health and HIV and the Royal College of General Practitioners and are based on expert opinion and observational studies [BASHH, 2004; RCGP and BASHH, 2006; BASHH, 2007].
Referral to a service specializing in sexual health
Referral to a service specializing in sexual health or a general practice providing an enhanced sexual health service is advised to attempt to confirm the diagnosis by microscopy of a wet-mount preparation in which characteristic motile, flagellated protozoa can be seen [Mabey et al, 2006].
Testing in primary care is often impractical (for example, due to a lack of immediate access to microscopy) and reduces the chance of detecting trichomoniasis compared with a setting where microscopy is available on-site.
Management
Management
Ideally, people with suspected trichomoniasis should be assessed and treated by a service specializing in sexual health, or a general practice providing an enhanced sexual health service. However, CKS acknowledges that this may not always be possible, so the following advice for this situation is offered.
Diagnosis - women: covers the diagnosis of trichomoniasis in women.
Diagnosis - men: covers the diagnosis of trichomoniasis in men.
Scenario: Management - women: covers the management of trichomoniasis in women, including pregnant women, and their partners.
Scenario: Trichomoniasis - men: covers the management of trichomoniasis in men, and their partners.
Scenario: Management - women
Scenario: Management of trichomoniasis in women
Advice
What advice should I give to a woman with trichomoniasis?
Explain that trichomoniasis is a sexually transmitted infection (STI) and advise:
Sexual abstinence (including abstaining from oral sex) until treatment is completed and any partners have also been treated and followed up.
The use of condoms to reduce the risk of further infection and exposure to other STIs.
Basis for recommendation
Basis for recommendation
These recommendations are from guidelines developed by the British Association of Sexual Health and HIV and the Royal College of General Practitioners, and are based on expert opinion [RCGP and BASHH, 2006; BASHH, 2007].
Management (not pregnant)
How do I manage trichomoniasis in women who are not pregnant?
Ideally, treatment should be provided by a service specializing in sexual health or a general practice providing an enhanced sexual health service.
If this is not possible:
Offer metronidazole 400 mg twice a day for 5–7 days.
Alternative regimens (not recommended in pregnant or breastfeeding women) are:
Metronidazole 2 g as a single dose — if compliance is a problem.
Tinidazole 2 g orally in a single dose — if metronidazole is not tolerated.
Intravaginal metronidazole is not recommended.
Screen for coexisting sexually transmitted infections and advise contact tracing.
After completion of treatment, follow up to review symptoms, confirm that contact tracing has been carried out, and discuss the results of the sexually transmitted infection screen.
Do not routinely test to confirm cure.
Repeat testing for trichomoniasis is only recommended if symptoms persist after treatment or recur after treatment is completed.
Although rare, consider the possibility of sexual abuse in any child or young person with trichomoniasis, particularly in the following circumstances:
The child is younger than 13 years of age, unless there is clear evidence of mother-to-child transmission during birth, or of blood contamination.
The young person is 13 to 15 years of age, unless there is clear evidence of mother-to-child transmission during birth, blood contamination, or that the STI was acquired from consensual sexual activity with a peer.
The young person is 16 to 17 years of age and there is no clear evidence of blood contamination or that the STI was acquired from consensual sexual activity and there is a clear difference in power or mental capacity between the young person and their sexual partner, in particular when the relationship is incestuous or with a person in a position of trust (such as a teacher, sports coach, minister of religion) or there is concern that the young person is being exploited.
Follow appropriate child protection procedures and refer to a paediatrician if necessary.
Basis for recommendation
Basis for recommendation
These recommendations are from guidelines developed by the British Association of Sexual Health and HIV [BASHH, 2007] and the Health Protection Agency with the Association of Medical Microbiologists [HPA and Association of Medical Microbiologists, 2008]. The aim of treatment is to eradicate the organism, relieve symptoms, if present, and prevent transmission to partners.
Metronidazole
There is evidence that metronidazole is more effective than placebo for treating trichomoniasis in women [Forna and Gülmezoglu, 2003].
There is evidence from two trials that oral treatment is more effective than intravaginal treatment [Forna and Gülmezoglu, 2003]. This is because of the high incidence of infection of the urethra and paraurethral glands [BASHH, 2007].
Single high-dose metronidazole treatment may improve compliance, but is offered as a second-line option because there is evidence of an increased risk of adverse effects [Forna and Gülmezoglu, 2003], and a higher failure rate, especially if partners are not treated at the same time [BASHH, 2007]. People treated over 5–7 days are protected from reinfection during the time they are taking metronidazole; this protection is not as reliable with single dose treatments making it more important that any sexual partners are treated simultaneously [Cudmore et al, 2004].
Tinidazole
Tinidazole 2 g as a single dose is usually reserved for people who cannot tolerate, or who have failed to respond to, metronidazole [BNF 56, 2008].
It is better tolerated than metronidazole [Nailor and Sobel, 2007].
There is methodologically weak evidence that tinidazole may be more effective compared with metronidazole at single high doses for treating trichomoniasis, but there is less experience of its use in UK practice.
Management in pregnancy
How do I manage trichomoniasis in pregnant women?
Ideally, treatment should be provided by a service specializing in sexual health or a general practice providing an enhanced sexual health service.
If this is not possible:
For women with symptoms, offer metronidazole 400 mg twice a day for 5–7 days. For more information about the use of metronidazole in pregnant and breastfeeding women, see Additional information.
If the woman declines to take metronidazole, offer clotrimazole pessaries (unlicensed for this indication) at a dose of one 100 mg pessary daily for 6 days, but discuss with the woman that, although clotrimazole may help symptoms, it is unlikely to cure trichomoniasis.
Intravaginal metronidazole is not recommended.
If a pregnant woman without symptoms is incidentally found to have trichomoniasis, discuss promptly with the woman's obstetrician or a genitourinary medicine specialist to decide whether to treat.
Screen for coexisting sexually transmitted infections and advise contact tracing.
After completion of treatment, follow up to review symptoms, confirm that contact tracing has been carried out, and discuss the results of the sexually transmitted infection screen.
Do not routinely test to confirm cure.
Repeat testing for trichomoniasis is only recommended if symptoms persist after treatment or recur after treatment is completed.
Additional information
Additional information
Pregnancy
The use of metronidazole during pregnancy has not been shown to increase the risk of congenital abnormalities in humans [NTIS, 2008; Micromedex, 2009].
Early case reports suggested that metronidazole may cause human fetal toxicity, however no pattern of abnormalities was evident.
More recent reports from more than 1300 births involving prenatal exposure to metronidazole suggest that it is not associated with an increase in birth defects.
Two meta-analyses involving a total of 2683 cases found no increase in teratogenic risk following exposure to metronidazole in early pregnancy.
A more recent cohort study found no increased risk of congenital malformations in 228 cases of exposure to metronidazole, 86% of which occurred in the first trimester.
Further large case series have also failed to demonstrate an increased teratogenic risk associated with metronidazole.
Breastfeeding
Metronidazole has not been associated with adverse effects in breastfed infants [Passmore et al, 1988; Weiner and Buhimschi, 2004].
The standard 5–7 day oral regimen is preferred in breastfeeding as there are more data to suggest it is safe to use.
There is no consistent recommendation from experts on the use of the single 2 g dose during breastfeeding.
The manufacturer advises that high-dose regimens are not recommended during breastfeeding.
If it is considered essential to use the 2 g single oral dose (for example due to poor compliance), a washout period is recommended before resumption of breastfeeding; this can reasonably be achieved by taking the dose of metronidazole after the last breastfeed of the evening.
Basis for recommendation
Basis for recommendation
These recommendations are from guidelines developed by the British Association of Sexual Health and HIV [BASHH, 2007] and the Health Protection Agency with the Association of Medical Microbiologists [HPA and Association of Medical Microbiologists, 2008]. The aim of treatment is to eradicate the organism, relieve symptoms, if present, and prevent transmission to partners.
Metronidazole
There is evidence from a randomized controlled trial that treatment with high-dose metronidazole produces a cure in over 90% of pregnant women compared with around 35% of untreated women [Ross, 1983].
However, evidence from one trial [Klebanoff et al, 2001] included in a Cochrane systematic review [Gülmezoglu, 2002] suggests that treatment with metronidazole does not improve the outcome of pregnancy in women with trichomoniasis and may be associated with preterm delivery and low birthweight. This needs to be balanced against evidence that infection with T. vaginalis is associated with preterm delivery and low birthweight [Cotch et al, 1997; Hay and Czeizel, 2007].
CKS found no evidence for the use of 5 day or 7 day courses of metronidazole in pregnancy, but there is evidence from two placebo-controlled studies that they have a higher cure rate and cause less adverse effects in women who are not pregnant than single high-dose regimens [Forna and Gülmezoglu, 2003]. There is no consistent recommendation from experts on the use of the single 2 g dose in pregnancy, but it is not recommended by the drug manufacturer [ABPI Medicines Compendium, 2008; BNF 56, 2008].
There is evidence from two trials comparing intravaginal with oral metronidazole treatment (not specifically in pregnant women) that oral treatment is more effective [Forna and Gülmezoglu, 2003]. This is because of the high incidence of infection of the urethra and paraurethral glands [BASHH, 2007].
Tinidazole
Tinidazole is not recommended because experts suggest that it should be avoided in pregnant women until further data regarding its safety are available [Nanda et al, 2006].
There is limited information regarding the safety of tinidazole in pregnancy, although there are no reports of adverse outcomes after inadvertent exposure. Tinidazole is contraindicated in the first trimester of pregnancy [Micromedex, 2005].
Topical clotrimazole
Expert opinion suggests that metronidazole is the preferable treatment in symptomatic pregnant women, but that clotrimazole pessaries may have a place for symptomatic relief in those women who decline, or are unable to take, metronidazole. The suggested dose is from guidance from the Health Protection Agency [HPA and Association of Medical Microbiologists, 2008].
An open-label trial of 168 symptomatic women (pregnant women were excluded) compared oral metronidazole with clotrimazole vaginal tablets and found oral metronidazole to be more effective at both eradicating T. vaginalis and relieving symptoms [duBouchet et al, 1997].
Management of partners
How should current partners of a woman with trichomoniasis be managed?
Ideally, the sexual contacts of people with trichomoniasis should be treated by a service specializing in sexual health or a general practice providing an enhanced sexual health service.
Current partners of people with known trichomoniasis should be screened for trichomoniasis and other sexually transmitted infections and offered treatment regardless of the results.
Offer metronidazole 400 mg twice a day for 5–7 days.
Alternative regimens (not recommended in pregnancy or breastfeeding) are:
Metronidazole 2 g as a single dose — if compliance is a problem.
Tinidazole 2 g orally in a single dose — if metronidazole is not tolerated.
Basis for recommendation
Basis for recommendation
The recommendation to screen and treat contacts of people with trichomoniasis is from guideline developed by the British Association of Sexual Health and HIV [BASHH, 2007] and is based on evidence from randomized controlled trials which showed that treatment of the partners of women with trichomoniasis reduced the relapse rate.
Treatment failure (not pregnant)
How should I manage treatment failure in women who are not pregnant?
If symptoms persist after treatment or if symptoms recur after the course of treatment has been completed, treatment should ideally be provided by a service specializing in sexual health or a general practice providing an enhanced sexual health service. If this is not possible:
Check compliance — ask if the metronidazole has caused vomiting.
Exclude the possibility of reinfection. Check that any partners have been treated appropriately and simultaneously.
Reconsider the diagnosis. Review the swab results and ensure that other causes of vaginal discharge have been excluded. For more information, see the CKS topic on Vaginal discharge.
Send a high vaginal swab (from the posterior fornix) for laboratory testing.
The swab should be stored in transport medium (such as Amie's or Stuart's), should be refrigerated before transportation, and ideally should arrive at the laboratory within 6 hours.
If culture is used by the laboratory, leave 48 hours after the end of treatment before testing.
If the swab results confirm persistent infection or reinfection with trichomoniasis:
If metronidazole was given as the initial treatment:
Offer a repeat course of oral metronidazole 400 mg twice a day for 7 days.
Tinidazole 2 g as a single dose is an alternative, particularly if resistance to metronidazole is suspected (when other causes of treatment failure have been ruled out).
If tinidazole was given as the initial treatment, offer a course of oral metronidazole 400 mg twice a day for 7 days (unless metronidazole is known not to be tolerated).
If a repeat course of metronidazole or a dose of tinidazole is unsuccessful, seek advice from a specialist in genito-urinary medicine.
Basis for recommendation
Basis for recommendation
These recommendations are based on expert opinion in a guideline developed by the British Association of Sexual Health and HIV [BASHH, 2007] and a review on the treatment of metronidazole-resistant cases [Cudmore et al, 2004].
Recommended treatments
A repeat course of oral metronidazole is often effective in people who fail to respond to the first course of treatment [BASHH, 2007]. There is no evidence to guide the dose and duration of metronidazole in treatment failure, but it would seem logical to use a 7 day course in preference to a 5 day course or a single high dose.
There is methodologically weak evidence from small trials that tinidazole may be more effective compared with metronidazole at single high doses for treating trichomoniasis [Forna and Gülmezoglu, 2003], but it is usually reserved for use in treatment failure because there is less experience of its use in UK practice. Resistance to metronidazole is uncommon. Cross-resistance among nitroimidazoles does occur, but is incomplete [Cudmore et al, 2004].
Treatments not recommended
Other treatment options recommended by experts include high doses of metronidazole or tinidazole if initial treatment fails [BASHH, 2007]; as these are higher than the licensed doses, CKS does not recommend their use in primary or non-specialist care.
Intravaginal treatment is not recommended as there is limited evidence that oral treatment is more effective than topical treatment for trichomoniasis [Forna and Gülmezoglu, 2003].
Treatment failure in pregnancy
How should I manage treatment failure in pregnant women?
If symptoms persist after treatment or if symptoms recur after the course of treatment has been completed, treatment should ideally be provided by a service specializing in sexual health or a general practice providing an enhanced sexual health service. If this is not possible:
Check compliance — ask if the metronidazole has caused vomiting.
Exclude the possibility of reinfection. Check that any partners have been treated appropriately and simultaneously.
Reconsider the diagnosis. Review the swab results and ensure that other causes of vaginal discharge have been excluded. For more information, see the CKS topic on Vaginal discharge.
Send a high vaginal swab (from the posterior fornix) for laboratory testing.
The swab should be stored in transport medium (such as Amie's or Stuart's), should be refrigerated before transportation, and ideally should arrive at the laboratory within 6 hours.
If culture is used by the laboratory, leave 48 hours after the end of treatment before testing.
If the swab results confirm persistent infection or reinfection with trichomoniasis, discuss with a genito-urinary medicine specialist or the woman's obstetrician before prescribing further treatment.
Basis for recommendation
Basis for recommendation
These recommendations are from a guideline developed by the British Association of Sexual Health and HIV and are based on expert opinion [BASHH, 2007].
There is evidence suggesting potential adverse pregnancy outcomes from metronidazole treatment, therefore CKS does not advise repeated courses of metronidazole without seeking specialist advice.
Scenario: Trichomoniasis - men
Scenario: Management of trichomoniasis in men
Advice
What advice should I give to a man with trichomoniasis?
Explain that trichomoniasis is a sexually transmitted infection (STI) and advise:
Sexual abstinence (including abstaining from oral sex) until treatment is completed and any partners have also been treated and followed up.
The use of condoms to reduce the risk of further infection and acquisition of other STIs.
Basis for recommendation
Basis for recommendation
These recommendations are from guidelines developed by the British Association of Sexual Health and HIV and the Royal College of General Practitioners, and are based on expert opinion [RCGP and BASHH, 2006; BASHH, 2007].
Management
How do I manage trichomoniasis in men?
Ideally, management should be provided in a service specializing in sexual health or a general practice providing an enhanced sexual health service.
If this is not possible:
Offer metronidazole 400 mg twice a day for 5–7 days.
Alternative regimens are:
Metronidazole 2 g as a single dose — if compliance is a problem.
Tinidazole 2 g orally in a single dose — if metronidazole is not tolerated.
Screen for coexisting sexually transmitted infections and advise contact tracing.
After completion of treatment, follow up people with trichomoniasis who have not been managed by a specialist service, to review symptoms, confirm contact tracing has been carried out, and discuss the results of the sexually transmitted infection screen.
Do not routinely test to confirm cure.
Repeat testing for trichomoniasis is only recommended if symptoms persist after treatment or recur after treatment is completed.
Although rare, consider the possibility of sexual abuse in any child or young person with trichomoniasis, particularly in the following circumstances:
The child is younger than 13 years of age, unless there is clear evidence of mother-to-child transmission during birth, or of blood contamination.
The young person is 13 to 15 years of age, unless there is clear evidence of mother-to-child transmission during birth, blood contamination, or that the STI was acquired from consensual sexual activity with a peer.
The young person is 16 to 17 years of age and there is no clear evidence of blood contamination or that the STI was acquired from consensual sexual activity and there is a clear difference in power or mental capacity between the young person and their sexual partner, in particular when the relationship is incestuous or with a person in a position of trust (such as a teacher, sports coach, minister of religion) or there is concern that the young person is being exploited.
Follow appropriate child protection procedures and refer to a paediatrician if necessary.
Basis for recommendation
Basis for recommendation
These recommendations are from guidelines developed by the British Association of Sexual Health and HIV [BASHH, 2007] and the Health Protection Agency with the Association of Medical Microbiologists [HPA and Association of Medical Microbiologists, 2008]. The aim of treatment is to eradicate the organism, relieve symptoms, if present, and prevent transmission to partners.
Metronidazole
There are no studies investigating the treatment of trichomoniasis in men, therefore recommendations were extrapolated from randomized controlled trial evidence in a Cochrane systematic review that found that metronidazole is effective for the treatment of trichomoniasis in women [Forna and Gülmezoglu, 2003].
A longer course of treatment has been recommended first-line because although single high-dose metronidazole treatment may improve compliance, there is evidence from two placebo-controlled studies in women of an increased risk of adverse effects with single high-dose metronidazole compared with a 5–7 day course [Forna and Gülmezoglu, 2003], and a higher failure rate, especially if partners are not treated at the same time [BASHH, 2007]. People treated over a 7-day period are protected from reinfection during the time they are taking metronidazole. This protection is not as reliable with single-dose treatments making it more important that any sexual partners are treated simultaneously [Cudmore et al, 2004].
Tinidazole
Tinidazole 2 g as a single dose is usually reserved for people who cannot tolerate, or who have failed to respond to, metronidazole [BNF 56, 2008]. For trichomoniasis, there is methodologically weak evidence from small trials that tinidazole may be more effective compared with metronidazole at single high doses in women [Forna and Gülmezoglu, 2003] but there is less experience of its use in UK practice.
Management of partners
How should current partners of men with trichomoniasis be managed?
Ideally, the sexual contacts of people with trichomoniasis should be treated by a service specializing in sexual health or a general practice providing an enhanced sexual health service.
Current partners of people with known trichomoniasis should be screened for trichomoniasis and other sexually transmitted infections, and offered treatment regardless of the results.
Offer metronidazole 400 mg twice a day for 5–7 days.
Alternative regimens (not recommended in pregnancy or breastfeeding) are:
Metronidazole 2 g as a single dose — if compliance is a problem.
Tinidazole 2 g orally in a single dose — if metronidazole is not tolerated.
Basis for recommendation
Basis for recommendation
The recommendation to screen and treat contacts of people with trichomoniasis is from guideline developed by the British Association of Sexual Health and HIV [BASHH, 2007] and is based on evidence from randomized controlled trials which showed that treatment of the partners of women with trichomoniasis reduced the relapse rate.
Treatment failure
How should I manage treatment failure in men?
If symptoms persist after treatment or if symptoms recur after the course of treatment has been completed, treatment should ideally be provided by a service specializing in sexual health or a general practice providing an enhanced sexual health service. If this is not possible:
Check compliance — ask if the metronidazole has caused vomiting.
Exclude the possibility of reinfection. Check that any partners have been treated appropriately and simultaneously.
Reconsider the diagnosis. Review the swab results and ensure other causes of urethritis have been excluded. For more information, see the CKS topic on Urethritis - male.
Send a urethral swab for laboratory testing (usually microscopy) and state on the form that trichomoniasis is suspected.
The swab should be stored in transport medium (such as Amie's or Stuart's), should be refrigerated before transportation, and ideally should arrive at the laboratory within 6 hours.
If culture is used by the laboratory, leave 48 hours after the end of treatment before testing.
Some laboratories may accept a first-void urine specimen, but it is advisable to check with local services first.
If the swab results confirm persistent infection or reinfection with trichomoniasis:
If metronidazole was given as the initial treatment:
Offer a repeat course of oral metronidazole 400 mg twice a day for 7 days.
Tinidazole 2 g as a single dose is an alternative, particularly if resistance to metronidazole is suspected (when other causes of treatment failure have been ruled out).
If tinidazole was given as the initial treatment, offer a course of oral metronidazole 400 mg twice a day for 7 days (unless metronidazole is known to be not tolerated).
If a repeat course of metronidazole or a dose of tinidazole is unsuccessful, seek advice from a specialist in genito-urinary medicine.
Basis for recommendation
Basis for recommendation
These recommendations are based on expert opinion in a guideline developed by the British Association of Sexual Health and HIV [BASHH, 2007] and a review on the treatment of metronidazole-resistant cases [Cudmore et al, 2004].
Recommended treatments
Metronidazole: there is no evidence to guide dose and duration in treatment failure, but it is logical to use a 7-day course in preference to a 5-day course or a single high dose.
Tinidazole is a second-line option because resistance to metronidazole is uncommon. Cross-resistance among nitroimidazoles does occur, but is incomplete [Cudmore et al, 2004].
Treatments not recommended
Other treatment options recommended by experts include high doses of metronidazole or tinidazole if initial treatment fails [BASHH, 2007]; as these are higher than the licensed doses, CKS does not recommend their use in primary care.
Evidence
Evidence
Supporting evidence
Treatments in women
Evidence on treatments for trichomoniasis in women
Oral nitroimidazoles (metronidazole and tinidazole) are effective in the treatment of trichomoniasis. Intravaginal treatment is less effective than oral treatment. There is evidence to suggest that adverse effects are less likely with a longer treatment course rather than the single-dose treatment. There is insufficient comparative evidence between drugs.
A Cochrane systematic review (search date: 2002) studied interventions for treating trichomoniasis in women who were not pregnant [Forna and Gülmezoglu, 2003].
Metronidazole treatment compared with placebo:
One randomized controlled trial (n = 429) compared women who were given oral metronidazole (250 mg three times a day for 10 days), oral metronidazole at the same dose combined with vaginal metronidazole (500 mg daily for 10 days), and placebo (either oral alone, or oral and vaginal) over 10 days. After 6 weeks only 18 out of 287 (6%) women in the treatment groups still had trichomoniasis compared with 111 out of 142 (78%) of women in the placebo groups (risk ratio [RR] 0.08, 95% CI 0.05 to 0.13).
Short (single dose) compared with longer treatment courses:
Comparison of a single dose of metronidazole 2 g with a 5–7 day course of metronidazole in two double-blind, placebo-controlled studies (n = 294) showed an 88% cure rate in the women who had a short course, and a 92% cure rate in women with a long course of metronidazole. There were more adverse effects in the single-dose group (RR 2.7, 95% CI 1.62 to 4.49). Nausea and vomiting accounted for most of this difference.
Two randomized, blinded trials (n = 261) compared different doses of short-treatment metronidazole and found a lower dose (1 gram or less) to be less effective than a high dose (1.5 g or 2 g) at curing trichomoniasis (RR 2.97, 95% CI 1.92 to 4.59). Both doses had similar rates of adverse effects.
Oral compared with intravaginal treatment:
Two small randomized trials (n = 94) compared oral and intravaginal metronidazole treatment. Loss to follow up occurred in both trials, but oral treatment was better at achieving parasitological cure (RR 0.20, 95% CI 0.07 to 0.56).
Oral metronidazole compared with oral tinidazole:
Oral metronidazole was compared with tinidazole in eight studies (n = 595). All compared short regimens. However, the results from these studies should be interpreted with caution as there was a lack of blinding in the assessment of outcomes. The Cochrane meta-analysis showed metronidazole treatment had a statistically significant higher risk of:
Treatment failure (RR 3.24, 95% CI 1.66 to 6.32).
Clinical failure (RR 3.81, 95% CI 1.83 to 7.90).
Adverse effects (RR 1.65, 95% CI 1.35 to 2.02).
Treatments in pregnant women
Evidence on treatments for trichomoniasis in pregnant women
Metronidazole is effective for treating trichomoniasis in pregnancy. However, the effect of metronidazole on pregnancy outcomes is uncertain and it may increase the risk of preterm delivery and low birthweight babies. Further research is needed.
A Cochrane systematic review (search date: 2004) identified two randomized trials of treatment for trichomoniasis in pregnancy [Gülmezoglu, 2002].
One US randomized, placebo-controlled trial included only asymptomatic women (n = 617) between 16 and 23 weeks' gestation. The dose of metronidazole was double the usual recommended dose (two 2 g doses of metronidazole, 48 hours apart) and treatment was repeated at follow up (24–29 weeks' gestation) [Klebanoff et al, 2001].
Follow-up swabs were available for 529 women. Parasitological cure was achieved in 249 out of 269 (93%) women treated with metronidazole and 92 out of 260 (35%) women in the placebo group.
Delivery before 37 weeks' gestation occurred in 60 out of 315 (19%) women in the metronidazole group and 31 out of 289 (11%) women in the placebo group (relative risk [RR] 1.8, 95% CI 1.2 to 2.7, p = 0.004).
Low birthweight (defined as < 2500 g) was more common in the metronidazole group (51 out of 315 [16%]) compared with the placebo group (34 out of 289 [12%]), but this was not statistically significant (RR 1.4, 95% CI 0.9 to 2.1).
It is not clear to what extent these results can be extrapolated to current UK practice. The women involved in this study were asymptomatic and the dose of metronidazole was higher than normal recommended doses.
The second study (n = 376) was randomized by alternate allocation and included both asymptomatic and symptomatic women [Ross, 1983]. They were given metronidazole 2 g as a single oral dose, or no treatment (no placebo was used). This study was of poor methodological quality therefore the results should be interpreted with caution.
Parasitological cure was achieved in 77 out of 83 (93%) women treated with metronidazole and 30 out of 91 (33%) women given no treatment.
There were no significant differences in mean birthweight or gestational age between the two groups.
Effect on pregnancy outcome
Evidence on the effect of trichomoniasis on pregnancy outcome
Pregnant women with trichomoniasis are more likely to have a low birthweight infant, preterm delivery, or preterm delivery of a low birthweight infant. It is uncertain whether trichomoniasis in pregnancy causes premature membrane rupture.
In a large prospective trial, 1736 of 13,914 (12.6%) women at 23–26 weeks of gestation tested positive for Trichomonas vaginalis by culture and were followed up until delivery [Cotch et al, 1997]. Vaginal infection with T. vaginalis at mid-gestation was significantly associated with:
Low birthweight (odds ratio [OR] 1.3, 95% CI 1.1 to 1.5).
Preterm delivery (OR 1.3, 95% CI 1.1 to 1.4).
Preterm delivery of a low birthweight infant (OR 1.4, 95% CI 1.1 to 1.6).
The study found no association with T. vaginalis colonization and premature membrane rupture.
However, the risks calculated may not be applicable to other populations of women. In this study, women testing positive for T. vaginalis were more likely to be black, never married, less educated, economically disadvantaged, and to be cigarette smokers.
A subsequent review also discussed several smaller studies published prior to this prospective trial [Hay and Czeizel, 2007]. The review suggested that T. vaginalis in pregnancy was associated with preterm delivery, low birthweight, and low birthweight with preterm delivery, and found one study which identified an association between T. vaginalis infection and premature membrane rupture.
Treatments in men
Evidence on treatments for trichomoniasis in men
CKS found no evidence on treatments for trichomoniasis in men. Therefore, evidence from trials in women has been extrapolated when making recommendations.
Search strategy
Scope of search
A literature search was conducted for guidelines, systematic reviews and randomized controlled trials on primary care management of trichomoniasis, with additional searches in the following areas:
diagnosis of trichomoniasis
treatment of trichomoniasis in non-pregnant, pregnant and breastfeeding women
treatment failure
clotrimazole pessaries for symptomatic treatment of trichomoniasis in pregnant women
Search dates
July 2005 – December 2008
Key search terms
Various combinations of searches were carried out. The terms listed below are the core search terms that were used for Medline and these were adapted for other databases. Further details are available on request.
exp Trichomonas Vaginitis/, exp Trichomonas Infections/, exp Trichomonas vaginalis/, trichomoniasis.tw.
exp Clotrimazole/, clotrimazole.tw
Table 1. Key to search terms.| Search commands | Explanation |
|---|---|
| / | indicates a MeSH subject heading with all subheadings selected |
| .tw | indicates a search for a term in the title or abstract |
| exp | indicates that the MeSH subject heading was exploded to include the narrower, more specific terms beneath it in the MeSH tree |
| $ | indicates that the search term was truncated (e.g. wart$ searches for wart and warts) |
Topic specific literature search sources
British Association for Health and HIV (BASHH)
RCOG (Faculty of Sexual and Reproductive Healthcare)
Sources of guidelines
National Institute for Health and Clinical Excellence (NICE)
Scottish Intercollegiate Guidelines Network (SIGN)
National Guidelines Clearinghouse
British Columbia Medical Association
Institute for Clinical Systems Improvement
Guidelines International Network
National Library of Guidelines
National Health and Medical Research Council (Australia)
University of Michigan Medical School
Michigan Quality Improvement Consortium
National Resource for Infection Control
NHS Scotland National Patient Pathways
Agency for Healthcare Research and Quality
UK Ambulance Service Clinical Practice Guidelines
RefHELP NHS Lothian Referral Guidelines
Medline (with guideline filter)
Sources of systematic reviews and meta-analyses
Systematic reviews
Protocols
Database of Abstracts of Reviews of Effects
Medline (with systematic review filter)
EMBASE (with systematic review filter)
Sources of health technology assessments and economic appraisals
NIHR Health Technology Assessment programme
NHS Economic Evaluations
Health Technology Assessments
Canadian Agency for Drugs and Technologies in Health
International Network of Agencies for Health Technology Assessment
Sources of randomized controlled trials
Central Register of Controlled Trials
Medline (with randomized controlled trial filter)
EMBASE (with randomized controlled trial filter)
Sources of evidence based reviews and evidence summaries
DynaMed
Central Services Agency COMPASS Therapeutic Notes
Sources of national policy
Health Management Information Consortium (HMIC)
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