Differential Diagnosis for Vaginal Fishy Smells

• Single most likely diagnosis
  • Bacterial Vaginosis (BV): This is the most common cause of vaginal fishy smells. BV occurs when there is an imbalance in the normal vaginal flora, with an overgrowth of anaerobic bacteria. The fishy odor is due to the production of amines by these bacteria.
• Other Likely diagnoses
  • Trichomoniasis: A sexually transmitted infection caused by the parasite Trichomonas vaginalis. It can cause a foul-smelling vaginal discharge, which may be described as fishy.
  • Vulvovaginal Candidiasis: Although typically associated with a yeasty odor, some cases of candidiasis can produce a fishy smell, especially if there is a secondary bacterial infection.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
  • Cervical or Endometrial Cancer: Although rare, advanced cervical or endometrial cancer can cause a foul-smelling vaginal discharge. It is crucial to rule out these conditions, especially in postmenopausal women or those with risk factors.
  • Pelvic Inflammatory Disease (PID): PID is an infection of the female reproductive organs that can cause a foul-smelling discharge. If left untreated, PID can lead to serious complications, such as infertility and chronic pelvic pain.
• Rare diagnoses
  • Foreign Body: A retained foreign body, such as a forgotten tampon, can cause a foul-smelling vaginal discharge.
  • Desquamative Inflammatory Vaginitis (DIV): A rare condition characterized by a severe inflammatory response in the vagina, which can cause a foul-smelling discharge.
  • Fistula: A fistula between the vagina and the rectum or bladder can cause a foul-smelling vaginal discharge due to the presence of fecal or urinary matter in the vagina.