Different causes of vaginitis for the USMLE Step 2 CK exam

by / Tuesday, 08 June 2010 / Published in OB/GYN


  • The most common presenting symptom is discharge
  • Always rule out chemical or allergic causes
  • 50% of cases are due to Gardnerella
  • 25% due to Trichomonas
  • 25% due to Candida

Differentiating between the different causes of vaginitis

  Candida Trichomonas Gardnerella
Vaginal pH 4-5 >6 >5
Odor NONE RANCID “Fishy” on KOH
Discharge Cottage Cheese-like Green, frothy Variable
Si/Sx Itching, burning, swollen Severe itching Variable, none
Microscopy Pseudohyphae Motile Organisms Clue cells
Treatment Fluconazole Metronidazole Metronidazole


Candida Albicans – note the pseudohyphae





 Trichomonas – Motile Organisms


Gardnerella – Clue Cells (large epithelial cells covered with small bacteria)


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