White Smelly Vaginal Discharge After Sex: Causes (BV, Yeast, Trich, STIs) and Treatment

Post-Coital Vaginal Discharge: Differential Diagnosis

New or changed discharge after intercourse suggests infection or microbiome disruption. Key causes:

Bacterial Vaginosis (BV)

• Overgrowth of anaerobes (Gardnerella, Prevotella); ↓ lactobacilli.
• Thin, white/gray discharge; fishy odor (amine release) worsened by semen (alkaline).
• Rx: Metronidazole (oral/vaginal), clindamycin, secnidazole, tinidazole.

Vulvovaginal Candidiasis (Yeast)

• Candida albicans overgrowth.
• Thick, white, curdy discharge; intense pruritus, burning, erythema.
• Rx: Fluconazole 150 mg PO ×1; topical azoles (1–7 days).

Trichomoniasis

• Trichomonas vaginalis (protozoan).
• Frothy, yellow-green discharge; strawberry cervix; pruritus, dysuria.
• Rx: Metronidazole 2 g single dose (both partners); avoid alcohol.

Chlamydia / Gonorrhea

• Often asymptomatic; if symptoms: mucopurulent discharge, bleeding, pelvic pain.
• NAAT testing; treat per CDC guidelines (azithromycin/doxycycline + ceftriaxone).

Pelvic Inflammatory Disease (PID)

• Ascending infection → endometritis, salpingitis, peritonitis.
• Discharge + pelvic pain + fever + cervical motion tenderness.
• Empiric broad-spectrum antibiotics (ceftriaxone + doxycycline ± metronidazole).

Action

See clinician for speculum exam, pH, whiff test, microscopy, NAATs. Treat partners. Avoid douching.