Reproductive · PANCE / PANRE

Candidal Vulvovaginitis

Yeast infection of the vulva/vagina — thick white discharge, intense pruritus, normal pH.

Also known as: yeast infection, candidiasis, vulvovaginal candidiasis, VVC, monilial vaginitis

Overview

Symptomatic vulvar and vaginal inflammation caused by Candida species, most commonly Candida albicans (~85-90%), with C. glabrata, C. krusei, and C. tropicalis accounting for non-albicans cases that are often azole-resistant.

Epidemiology

Affects ~75% of women at least once; ~5-8% experience recurrent vulvovaginal candidiasis (RVVC, ≥3 episodes/year). Second most common cause of vaginitis after BV.

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Question 1ReproductiveEasy
A 32-year-old woman presents with 3 days of vulvar itching, burning, and thick white discharge. She was started on azithromycin 5 days ago for community-acquired pneumonia and takes quetiapine nightly for bipolar disorder. Pelvic exam reveals erythematous vulva with curd-like discharge; KOH prep shows pseudohyphae and budding yeast. ECG from her last admission showed a QTc of 470 ms. Which of the following is the most appropriate treatment?
  • AIntravaginal metronidazole
  • BIntravaginal clotrimazole
  • COral itraconazole
  • DOral fluconazole
Reveal answer & full explanation
Correct answer: B — Intravaginal clotrimazole
  • AIntravaginal metronidazole
  • BIntravaginal clotrimazole
  • COral itraconazole
  • DOral fluconazole

Why Intravaginal clotrimazole is correct

  • This patient has uncomplicated vulvovaginal candidiasis: vulvar itching and burning, curd-like discharge, and a KOH prep showing pseudohyphae and budding yeast
  • The decisive issue is medication-related QT risk — azithromycin and quetiapine both prolong the QT interval, and her baseline QTc is already borderline-prolonged at 470 ms
  • Intravaginal azoles (clotrimazole, miconazole, terconazole) are highly effective for uncomplicated candidiasis and have negligible systemic absorption, so they avoid additive QT prolongation
  • For uncomplicated disease, topical and oral azoles are equally effective, so safety is the tie-breaker and the topical agent is the most appropriate choice

Why the others are wrong

  • Intravaginal metronidazole — treats bacterial vaginosis and trichomoniasis and has no activity against Candida; buzzword-match trap, since 'vaginal discharge' pattern-matches to metronidazole but the KOH pseudohyphae and budding yeast identify yeast, not clue cells or motile trichomonads
  • Oral itraconazole — an oral azole that also prolongs QT and inhibits CYP3A4, carrying the same additive torsades risk as fluconazole, and it is not first-line for vaginal candidiasis; right-diagnosis-wrong-route trap
  • Oral fluconazole — the textbook single-dose first-line for uncomplicated candidiasis, but it prolongs QT via hERG blockade and would compound the risk from azithromycin, quetiapine, and the elevated baseline QTc; premature-closure trap
Question 2ReproductiveEasy
A 24-year-old woman who is not pregnant has thick, white, 'cottage cheese' vaginal discharge with vulvar pruritus and burning. There is no malodor. A potassium hydroxide (KOH) prep of the discharge shows pseudohyphae and budding yeast. Which of the following is the most appropriate treatment?
  • AFluconazole 150 mg weekly for 6 months
  • BMetronidazole 500 mg BID for 7 days
  • CBoric acid vaginally for 14 days
  • DFluconazole 150 mg PO single dose
Reveal answer & full explanation
Correct answer: D — Fluconazole 150 mg PO single dose
  • AFluconazole 150 mg weekly for 6 months
  • BMetronidazole 500 mg BID for 7 days
  • CBoric acid vaginally for 14 days
  • DFluconazole 150 mg PO single dose

Why Fluconazole 150 mg PO single dose is correct

  • Thick, white, curd-like discharge without odor, intense vulvar pruritus, and a KOH prep showing pseudohyphae and budding yeast identify uncomplicated vulvovaginal candidiasis (Candida albicans).
  • Uncomplicated disease in a non-pregnant patient is treated with a single 150 mg oral dose of fluconazole or a short course of a topical azole, per current CDC STI guidance.
  • Recurrent disease (>=4 episodes per year) is treated with induction followed by weekly fluconazole maintenance.

Why the others are wrong

  • Fluconazole 150 mg weekly for 6 months — the suppressive regimen for recurrent vulvovaginal candidiasis and only after induction dosing; this woman has a single uncomplicated episode that a one-time 150 mg dose clears. Sets the overtreatment trap.
  • Metronidazole 500 mg BID for 7 days — treats bacterial vaginosis and trichomoniasis, not candidiasis; the absence of clue cells and odor with the presence of yeast exclude it. Sets the premature-closure trap of defaulting to the most common vaginitis regimen.
  • Boric acid vaginally for 14 days — reserved for azole-refractory or non-albicans species such as C. glabrata, which do not form pseudohyphae; the KOH findings here are those of C. albicans. Sets the second-line-before-first-line trap.
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Risk factors

  • Recent antibiotic use
  • Diabetes mellitus (especially poorly controlled)
  • Pregnancy (elevated estrogen)
  • Immunosuppression (HIV, chemotherapy, high-dose steroids)
  • Oral contraceptives with higher estrogen (modest)
  • Tight synthetic clothing, occlusive perineum
  • SGLT2 inhibitors (canagliflozin, empagliflozin, dapagliflozin)

Pathophysiology

Candida is a normal vaginal commensal in ~20% of women. Disruption of microbial balance (e.g., antibiotic-induced loss of Lactobacillus), local immune changes, or substrate availability (hyperglycemia, glucosuria from SGLT2 inhibitors) permits overgrowth and hyphal invasion of vaginal epithelium, producing inflammation.

Clinical presentation

Symptoms

  • Intense vulvar and vaginal pruritus (hallmark)
  • Burning, soreness, irritation
  • External dysuria (urine contacting inflamed vulva)
  • Dyspareunia
  • Thick white 'cottage cheese' discharge — odorless

Signs / physical exam

  • Vulvar erythema and edema, possible satellite lesions
  • Excoriations from scratching
  • Adherent white plaques on vaginal walls
  • No fishy odor

Classic findings

Woman after antibiotic use with severe vulvar itching, vulvar erythema, thick curd-like discharge, normal pH, and yeast/pseudohyphae on KOH prep.

Differential diagnosis

  • Bacterial vaginosis — Thin gray discharge, fishy odor, pH >4.5, clue cells, minimal pruritus
  • Trichomoniasis — Frothy yellow-green discharge, motile trichomonads, pH >4.5
  • Atrophic vaginitis — Postmenopausal, dryness; thin pale mucosa
  • Allergic / contact dermatitis — Recent product exposure; erythema and pruritus without discharge
  • Lichen sclerosus / lichen planus — Chronic vulvar pruritus, atrophic 'cigarette paper' or erosive changes; biopsy
  • Herpes simplex — Painful vesicles/ulcers, viral prodrome; PCR
  • Vulvodynia — Pain without identifiable cause; normal exam

Diagnostic workup

Labs

  • Vaginal pH normal (<4.5) — important distinguishing feature
  • 10% KOH wet mount: budding yeast, pseudohyphae (C. albicans) or budding yeast without pseudohyphae (C. glabrata)
  • Negative whiff test
  • Culture if recurrent, severe, or atypical (identifies non-albicans species and resistance)
  • Fasting glucose or A1c if recurrent — screen for undiagnosed diabetes
  • HIV testing if unusual recurrence or severity

Diagnostic algorithm

CategoryDefinitionFirst-line Treatment
Uncomplicated VVCSporadic, mild-moderate, C. albicans, immunocompetent hostFluconazole 150 mg PO × 1 OR topical azole 1-7 d
Severe VVCExtensive vulvar erythema, edema, excoriation, fissuresFluconazole 150 mg × 2 doses 72 h apart OR topical 7-14 d
Recurrent VVC≥3 episodes/yearInduction (3 doses fluconazole) + weekly suppression × 6 mo
Non-albicans VVCC. glabrata, C. krusei, etc.Boric acid 600 mg PV × 14 d, nystatin, ibrexafungerp
PregnancyAny trimesterTopical clotrimazole or miconazole × 7 d (no oral fluconazole)
VVC classification and treatment approach by CDC/ACOG.

Treatment

First-line

  • Uncomplicated: fluconazole 150 mg PO × 1 dose
  • Topical azole alternatives × 1-7 days: clotrimazole, miconazole, terconazole, tioconazole (available OTC)
  • Patient symptom relief usually within 24-48 hours

Complicated VVC (severe, recurrent, non-albicans, immunocompromised, pregnancy)

  • Severe disease: fluconazole 150 mg PO × 2 doses 72 hours apart, OR topical azole × 7-14 days
  • Recurrent (≥3 episodes/year): induction with fluconazole 150 mg q72h × 3 doses, then suppression with fluconazole 150 mg weekly × 6 months
  • Non-albicans (especially C. glabrata): intravaginal boric acid 600 mg suppositories nightly × 14 days OR nystatin vaginal tablets; resistant azoles
  • Ibrexafungerp (oral triterpenoid) — FDA-approved alternative for VVC and RVVC prevention

Pregnancy

  • Topical azoles only (clotrimazole, miconazole) × 7 days
  • Avoid oral fluconazole (associated with miscarriage at high doses; first-trimester safety concerns)

Complications

  • Recurrent infection (5-8%)
  • Vulvar excoriation and secondary bacterial infection
  • Persistent dyspareunia and quality-of-life impact
  • Increased risk of preterm delivery (controversial association in pregnancy)

PANCE pearls

  • Vaginal pH <4.5 helps distinguish candidiasis from BV (pH >4.5) and trichomoniasis (pH >4.5).
  • Treat the patient, not the lab — uncomplicated VVC may be diagnosed clinically; KOH wet mount has only ~50% sensitivity.
  • OTC azole self-treatment frequently fails (true VVC in only ~30% of women self-treating); confirm diagnosis when patients present with treatment failure.
  • Non-albicans species (especially C. glabrata) are often azole-resistant — boric acid is highly effective.
  • Recurrent VVC warrants evaluation for diabetes and consideration of HIV; also assess vulvar skin disease (lichen sclerosus) which may mimic chronic yeast infection.
  • Sexual partner treatment is not indicated for routine VVC.

References

  • CDC STI Guidelines 2021 — CDC Sexually Transmitted Infections Treatment Guidelines, 2021 (MMWR Recomm Rep 2021)
  • ACOG PB 215 — ACOG Practice Bulletin No. 215: Vaginitis in Nonpregnant Patients
  • IDSA 2016 — Clinical Practice Guideline for the Management of Candidiasis: 2016 Update by the IDSA (Pappas et al., CID 2016)

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