Clinical Characteristics of Common Vaginal Infections
Comparative Symptom Table
| Infection | Discharge Color | Discharge Consistency | Odor | Pruritus (Itch) | Vaginal pH |
|---|---|---|---|---|---|
| Gonorrhea | Yellow-white to purulent | Mucopurulent | Minimal to none | Minimal | Variable |
| Chlamydia | Yellow-white to clear | Mucopurulent | Minimal to none | Minimal | Variable |
| Bacterial Vaginosis | White to gray | Thin, homogeneous | Fishy (especially after intercourse) | Minimal to absent | >4.5 |
| Mycoplasma genitalium | Yellow-white | Mucopurulent | Minimal | Minimal | Variable |
| Trichomoniasis | Yellow-green | Profuse, frothy | Malodorous/musty | Moderate to severe | >4.5 |
| Candidiasis | White | Thick, cottage cheese-like | Minimal to none | Severe | ≤4.5 |
Detailed Clinical Presentations
Gonorrhea and Chlamydia
- Both infections frequently present with mucopurulent cervicitis (MPC) characterized by yellow endocervical exudate visible in the endocervical canal 1
- Approximately 53% to 100% of extragenital infections are asymptomatic or minimally symptomatic 6
- When symptomatic, patients may experience abnormal vaginal bleeding (especially post-coital) and mild discharge 1
- Pruritus is not a prominent feature of either infection 1
Bacterial Vaginosis
- Characterized by thin, white to gray homogeneous discharge with a distinctive fishy odor that intensifies after intercourse or with alkaline exposure 1, 4
- The "whiff test" (fishy odor after KOH application) is positive 3
- Pruritus is typically minimal or absent, distinguishing it from candidiasis 1, 5
- Approximately 50% of women meeting clinical criteria are asymptomatic 1
Mycoplasma genitalium
- Presents similarly to chlamydia with mucopurulent cervical discharge 6
- Yellow-white discharge with minimal odor 6
- Pruritus is not a characteristic feature 6
- Often asymptomatic, making clinical diagnosis challenging 6
Trichomoniasis
- Profuse, yellow-green, frothy discharge is the hallmark presentation 1, 5
- Malodorous or musty odor is common 1, 5
- Moderate to severe vulvar irritation and pruritus occur frequently 4, 5
- Approximately 70% of infections are asymptomatic 6
- Vaginal pH is elevated (>4.5) 1, 3
Vulvovaginal Candidiasis
- White, thick discharge resembling cottage cheese is pathognomonic 2, 4, 5
- Severe vulvar pruritus and burning are the most prominent symptoms 1, 4
- Odor is minimal or absent 2, 4
- Vaginal pH remains normal (≤4.5), distinguishing it from BV and trichomoniasis 3, 4
- Vulvar erythema and edema are common on examination 1, 4
Diagnostic Pearls
The combination of vaginal pH testing and microscopic examination of discharge provides rapid, accurate diagnosis in most cases 1, 3:
- pH >4.5 with fishy odor and clue cells = Bacterial vaginosis 3
- pH >4.5 with motile trichomonads = Trichomoniasis 3
- pH ≤4.5 with yeast/pseudohyphae and severe pruritus = Candidiasis 3, 4
- Mucopurulent cervical discharge requires testing for gonorrhea and chlamydia regardless of pH 1
Critical Caveat
Multiple infections can coexist simultaneously—14% to 16% of women with BV or candidiasis harbor concurrent sexually transmitted organisms 7. Therefore, the presence of one infection does not exclude others, and comprehensive testing is warranted when risk factors are present 7.