Trichomoniasis

Definition

The spectrum of sexually transmitted diseases includes the classic venereal diseases – gonorrhea, syphilis, chancroid, lymphogranuloma venereum, and granuloma inguinale – as well as a variety of other pathogens known to be spread by sexual contact (Table Sexually Transmitted Diseases). Common clinical syndromes associated with sexually transmitted diseases are listed in Table Selected Syndromes Associated with Common Sexually Transmitted Pathogens. The most current information on epidemiology, diagnosis, and treatment of sexually transmitted diseases provided by the Centers for Disease Control and Prevention can be found at http://www.cdc.gov.

TABLE. Sexually Transmitted Diseases

Disease	Associated Pathogens
Bacterial
Gonorrhea	Neisseria gonorrhoeae
Syphilis	Treponema pallidum
Chancroid	Hemophilus ducreyi
Granuloma inguinale	Calymmatobacterium granulomatis
Enteric disease	Salmonella spp., Shigella spp., Campylobacter fetus
Campylobacter infection	Campylobacter jejuni
Bacterial vaginosis	Gardnerella vaginalis, Mycoplasma hominis, Bacteroides spp., Mobiluncus spp.
Group B streptococcal infections	Group B Streptococcus
Chlamydial
Nongonococcal urethritis	Chlamydia trachomatis
Lymphogranuloma venereum	Chlamydia trachomatis, type L
Viral
Acquired immune-deficiency syndrome (AIDS)	Human immunodeficiency virus
Herpes genitalis	Herpes simplex virus, types I and II
Viral hepatitis	Hepatitis A, B, C, and D viruses
Condylomata acuminata	Human papillomavirus
Molluscum contagiosum	Poxvirus
Cytomegalovirus infection Mycoplasmal	Cytomegalovirus
Nongonococcal urethritis Protozoal	Ureaplasma urealyticum
Trichomoniasis	Trichomonas vaginalis
Amebiasis	Entamoeba histolytica
Giardiasis Fungal	Giardia lamblia
Vaginal candidiasis Parasitic	Candida albicans
Scabies	Sarcoptes scabiei
Pediculosis pubis	Phthirus pubis
Enterobiasis	Enterobius vermicularis

TABLE. Selected Syndromes Associated with Common Sexually Transmitted Pathogens

Syndrome	Commonly Implicated Pathogens	Common Clinical Manifestations^a
Urethritis	Chlamydia trachomatis, herpes simplex virus, Neisseria gonorrhoeae, Trichomonas vaginalis, Ureaplasma urealyticum	Urethral discharge, dysuria
Epididymitis	C. trachomatis, N. gonorrhoeae	Scrotal pain, inguinal pain, flank pain, urethral discharge
Cervicitis/vulvovaginitis	C. trachomatis, Gardnerella vaginalis, herpes simplex virus, human papillomavirus, N. gonorrhoeae, T. vaginalis	Abnormal vaginal discharge, vulvar itching/irritation, dysuria, dyspareunia
Genital ulcers (painful)	Hemophilus ducreyi, herpes simplex virus	Usually multiple vesicular/pustular (herpes) or papular/pustular (H. ducreyi) lesions that may coalesce; painful, tender lymphadenopathy^b
Genital ulcers (painless)	Treponema pallidum	Usually single papular lesion
Genital/anal warts	Human papillomavirus	Multiple lesions ranging in size from small papular warts to large exophytic condylomas
Pharyngitis	C. trachomatis (?), herpes simplex virus, N. gonorrhoeae	Symptoms of acute pharyngitis, cervical lymphadenopathy, fever^c
Proctitis	C. trachomatis, herpes simplex virus N. gonorrhoeae, T. pallidum	Constipation, anorectal discomfort, tenesmus, mucopurulent rectal discharge
Salpingitis	C. trachomatis, N. gonorrhoeae	Lower abdominal pain, purulent cervical or vaginal discharge, adnexal swelling, fever^d
^aFor some syndromes, clinical manifestations may be minimal or absent. ^bRecurrent herpes infection may manifest as a single lesion. ^cMost cases of pharyngeal gonococcal infection are asymptomatic. ^dSalpingitis increases the risk of subsequent ectopic pregnancy and infertility.

TABLE. Presentation of Gonorrhea Infections

	Males	Females
General	Incubation period 1-14 days Symptom onset in 2-8 days	Incubation period 1-14 days Symptom onset in 10 days
Site of infection	Most common – urethra Others – rectum (usually due to rectal intercourse in MSM), oropharynx, eye	Most common – endocervical canal Others – urethra, rectum (usually due to perineal contamination), oropharynx, eye
Symptoms	May be asymptomatic or minimally symptomatic Urethral infection – dysuria and urinary frequency Anorectal infection – asymptomatic to severe rectal pain Pharyngeal infection – asymptomatic to mild pharyngitis	May be asymptomatic or minimally symptomatic Endocervical infection – usually asymptomatic or mildly symptomatic Urethral infection – dysuria, urinary frequency Anorectal and pharyngeal infection – symptoms same as for men
Signs	Purulent urethral or rectal discharge can be scant to profuse Anorectal – pruritus, mucopurulent discharge, bleeding	Abnormal vaginal discharge or uterine bleeding; purulent urethral or rectal discharge can be scant to profuse
Complications	Rare (epididymitis, prostatitis, inguinal lymphadenopathy, urethral stricture) Disseminated gonorrhea	Pelvic inflammatory disease and associated complications (i.e., ectopic pregnancy, infertility) Disseminated gonorrhea (3 times more common than in men)

Gonorrhea

Syphilis

Chlamydia

Genital herpes

Trichomoniasis is caused by Trichomonas vaginalis, a flagellated, motile protozoan that is responsible for 3 to 5 million cases per year in the United States.
Coinfection with other sexually transmitted diseases (such as gonorrhea) is common in patients diagnosed with trichmoniasis.

Clinical presentation

The typical presentation of trichomoniasis in males and females is presented in Table Presentation of Trichomonas Infections.

TABLE. Treatment of Genital Herpes

Type of Infection	Recommended Regimens ^a^,b	Alternative Regimen
First clinical episode of genital herpes^c	Acyclovir 400 mg orally 3 times daily for 7-10 days, or Acyclovir 200 mg orally 5 times daily for 7-10 days, or Famciclovir 250 mg orally 3 times daily for 7-10 days, or Valacyclovir 1 g orally 2 times daily for 7-10 days	Acyclovir 5-10 mg/kg intravenous every 8 h for 2-7 days until clinical improvement occurs, followed by oral therapy to complete at least 10 days of total therapy^d
First clinical episode of herpes proctitis or oral infection including stomatitis or pharyngitis	Acyclovir 400 mg orally 5 times daily for 7-10 days^e	Acyclovir 5-10 mg/kg intravenous every 8 h for 2-7 days until clinical improvement occurs, followed by oral therapy to complete at least 10 days of total therapy^d
Recurrent infection
Episodic therapy	Acyclovir 400 mg orally 3 times daily for 5 days,^f or
	Acyclovir 800 mg orally 2 times daily for 5 days,^f or
	Famciclovir 125 mg orally 2 times daily for 5 days,^f or
	Valacyclovir 500 mg orally 2 times daily for 3-5 days,^f or
	Valacyclovir 1 g orally once daily for 5 days^f
	Acyclovir 400 mg orally twice daily,^g or
Suppressive therapy	Famciclovir 250 mg orally 2 times daily, or
Suppressive therapy	Valacyclovir 500 mg or 1000 mg orally once daily^h
^aRecommendations are those of the Centers for Disease Control. ^bHIV-infected patients may require more aggressive therapy. ^cPrimary or nonprimary first episode. ^dOnly for patients with severe symptoms or complications that necessitate hospitalization. ^eRecommendations based on studies utilizing this dosage regimen rather than the lower dosage regimens recommended for first clinical episodes of genital herpes. It is not clear whether lower dosage regimens would have comparable efficacy. Famciclovir and valacyclovir are probably also effective for proctitis and oral infection, but clinical experience is limited. ^fRequires initiation of therapy within 24 h of lesion onset or during the prodrome that precedes some outbreaks. ^gIndicated only for patients with frequent and/or severe recurrences; although safety and efficacy are documented in patients receiving acyclovir daily therapy for as long as 6 yr and valacyclovir and famciclovir therapy for 1 yr, it is recommended that therapy be discontinued periodically (e.g., once a year) to reassess the need for continued suppressive therapy. ^hValacyclovir 500 mg appears less effective than valacyclovir 1000 mg in patients with approximately 10 recurrences per year.

Diagnosis

T. vaginalis produces nonspecific symptoms also consistent with bacterial vaginosis, and thus laboratory diagnosis is required.
The simplest and most reliable means of diagnosis is a wet-mount examination of the vaginal discharge. Trichomoniasis is confirmed if characteristic pear-shaped, flagellating organisms are observed. Newer diagnostic tests such as monoclonal antibody or DNA probe techniques, as well as Polymerase chain reaction tests are highly sensitive and specific.

TABLE. Presentation of Trichomonas Infections

	Males	Females
General	Incubation period 3-28 days	Incubation period 3-28 days
General	Organism may be detectable within 48 hours after exposure to infected partner	Incubation period 3-28 days
Site of infection	Most common – urethra	Most common – endocervical canal
Site of infection	Others – rectum (usually due to rectal intercourse in MSM), oropharynx, eye	Others – urethra, rectum (usually due to perineal contamination), oropharynx, eye
Symptoms	May be asymptomatic (more common in males than females) or minimally symptomatic	May be asymptomatic or minimally symptomatic
	Urethral discharge (clear to mucopurulent)	Scant to copious, typically malodorous vaginal discharge (50-75%) and pruritus (worsen during menses)
	Dysuria, prurius	Dysuria, dyspareunia
Signs	Urethral discharge	Vaginal discharge
		Vaginal pH 4.5-6
		Inflammation/erythema of vulva, vagina, and/or cervix
		Urethritis
Complications	Epididymitis and chronic prostatitis (uncommon)	Pelvic inflammatory disease and associated complications (i.e., ectopic pregnancy, infertility)
	Male infertility (decreased sperm motility and viability)	Premature labor, premature rupture of membranes, and low-birth-weight infants (risk of neonatal infections is low)
	Male infertility (decreased sperm motility and viability)	Cervical neoplasia

TABLE. Treatment of Trichomoniasis

Type	Recommended Regimen^a	Alternative Regimen
Symptomatic and asymptomatic infections	Metronidazole 2 g orally in a single dose^b	Metronidazole 500 mg orally 2 times daily for 7 days^c
Treatment in pregnancy	Metronidazole 2 g orally in a single dose^d
Neonatal infections^e	Metronidazole 10-30 mg/kg daily for 5-8 days
Note: Tinidazole was approved by the FDA in 2004 for for the treatment of trichomonasis. The recommended dosage is 2 g orally in a single dose. ^aRecommendations are those of the Centers for Disease Control. ^bTreatment failures should be treated with metronidazole 500 mg orally 2 times daily for 7 days. Persistent failures should be managed in consultation with an expert. Metronidazole 2 g orally daily for 3-5 days has been effective in patients infected with T. vaginalis strains mildly resistant to metronidazole, but experience is limited; higher doses also have been used. ^cMetronidazole labeling approved by the FDA does not include this regimen. Dosage regimens for treatment of trichomoniasis included in the product labeling are the single 2 g dose; 250 mg 3 times daily for 7 days; and 375 mg 2 times daily for 7 days. The 250 mg and 375 mg dosage regimens are currently not included in the Centers for Disease Control recommendations. ^dMetronidazole is contraindicated in the first trimester of pregnancy. While the Centers for Disease Control recommends a single 2-g dose for treatment during pregnancy, a 7-day regimen is preferred by some since it produces lower peak serum drug concentrations. ^eOnly infants with symptomatic trichomoniasis or with urogenital trichomonal colonization that persists beyond the fourth week of life.

TABLE. Treatment Regimens for Miscellaneous Sexually Transmitted Diseases

Infection	Recommended Regimen^a	Alternative Regimen
Chancroid (Haemophilus ducreyi)	Azithromycin 1 g orally in a single dose, or Ceftriaxone 250 mg intramuscularly in a single dose, or Ciprofloxacin 500 mg orally 2 times daily for 3 days,^b or Erythromycin base 500 mg orally 4 times daily for 7 days
Lymphogranuloma venereum	Doxycycline 100 mg orally 2 times daily for 21 days	Erythromycin base 500 mg orally 4 times daily for 21 days
Human Papillomavirus Infection:
External genital warts	Provider-Administered Therapies: Cryotherapy (e.g., liquid nitrogen or cryoprobe), or Podophyllin 10-25% in compound tincture of benzoin applied to lesions; repeat weekly if necessary,^c, ^d or Trichloroacetic acid (TCA) 80-90% or bichloroacetic acid (BCA) 80-90% applied to warts; repeat weekly if necessary, or Surgical removal (tangential scissor excision, tangential shave excision, curettage, or electrosurgery) Patient-Applied Therapies: Podofilox 0.5% solution or gel applied 2 times daily for 3 days, followed by 4 days of no therapy; cycle is repeated as necessary for a total of 4 cycles,^d or Imiquimod 5% cream applied at bedtime 3 times weekly for up to 16 wk^d	Intralesional interferon or laser surgery
Human Papillomavirus Infection:
Vaginal, urethral meatus, and anal warts	Cryotherapy with liquid nitrogen, or TCA or BCA 80-90% as for external HPV warts; repeat weekly as necessary (not for urethral meatus warts), or Podophyllin 10-25% in compound tincture of benzoin applied at weekly intervals (not for vaginal or anal warts),^d or Surgical removal (not for vaginal or urethral meatus warts)
^aRecommendations are those of the Centers for Disease Control. ^cSome experts recommended washing podophyllin off after 1-4 h to minimize local irritation. ^bCiprofloxacin is contraindicated for pregnant and lactating women and for persons aged <18 yr. ^dSafety during pregnancy is not established.

Treatment

Metronidazole is the only antimicrobial agent available in the United States that is consistently effective in T. vaginalis infections.
Gastrointestinal complaints (e.g., anorexia, nausea, vomiting, diarrhea) are the most common adverse effects, with the single 2-g dose of metronidazole, occurring in 5% to 10% of treated patients. Some patients complain of a bitter metallic taste in the mouth.
Patients intolerant of the single 2-g dose because of gastrointestinal adverse effects usually tolerate the multidose regimen.
To achieve maximal cure rates and prevent relapse with the single 2-g dose of metronidazole, simultaneous treatment of infected sexual partners is necessary.
Patients who fail to respond to an initial course usually respond to a second course of metronidazole therapy.
Patients taking metronidazole should be instructed to avoid alcohol ingestion during therapy and for 1 to 2 days after completion of therapy because of a possible disulfiram-like effect.
At present, no satisfactory treatment is available for pregnant women with Trichomonas infections.

Evaluation of therapeutic outcomes

Follow-up is considered unnecessary in patients who become asymptomatic after treatment with metronidazole.
When patients remain symptomatic, it is important to determine if reinfection has occurred. In these cases, a repeat course of therapy, as well as identification and treatment or retreatment of infected sexual partners, is recommended.

Other sexually transmitted diseases

Several sexually transmitted diseases other than those previously discussed occur with varying frequency in the United States and throughout the world.