FFinalistSouthampton · 2027
Sexual health
AKT · Sexual health/Vaginitis / discharge

Trichomoniasis

Trichomonas vaginalis — flagellated protozoan

Overview

A sexually transmitted protozoal infection causing vaginitis/urethritis. Notable for the frothy discharge and "strawberry cervix", and for raising HIV transmission risk.

Recognise

  • Women: frothy yellow-green offensive discharge, vulval itch/soreness, dysuria; "strawberry cervix" (punctate haemorrhages)
  • Men: often asymptomatic; urethritis
  • Raised vaginal pH (>4.5)

Red flags

  • Pregnancy (preterm birth, low birth weight association)

Differentials & how to tell them apart

Bacterial vaginosisgrey non-itchy discharge, clue cells, no motile organisms
Candidiasiswhite itchy discharge, NORMAL pH, no strawberry cervix
Gonorrhoea/chlamydia cervicitisNAAT

Investigations

Wet-mount microscopy — motile flagellated trichomonads; NAAT most sensitive. Raised pH. Test for other STIs incl. HIV.

Management

Metronidazole 400–500 mg BD orally for 7 days

  1. 1Refer to GUM. Metronidazole 400–500 mg BD for 7 days (or 2 g single dose).Gate: The 2 g single dose is NOT recommended in pregnancy/breastfeeding → use 400 mg BD ×7d
  2. 2Pregnant/breastfeeding: metronidazole 400 mg BD ×7d; specialist advice if metronidazole-allergic.
Metronidazole — first-line; 400–500 mg BD ×7d (or 2 g single dose, not in pregnancy)

Key points

Unlike BV/candida, trichomonas IS an STI → partner treatment essential. Avoid alcohol with metronidazole.

Monitor & prognosis

Symptom resolution; re-test if persistent.

Good with treatment + partner treatment.

Source: NICE CKS Trichomoniasis (2025); BASHH