What is the best course of action for a pregnant patient experiencing a burning sensation and swelling of the vulva while being treated with nitrofurantoin (antibiotic) for a presumed urinary tract infection (UTI)?

Vulvar Burning and Swelling During Nitrofurantoin Treatment in Pregnancy

This presentation strongly suggests vulvovaginal candidiasis (VVC), a common complication during pregnancy that can be exacerbated by antibiotic therapy; the nitrofurantoin should be continued for the UTI while simultaneously treating the vulvovaginal candidiasis with a 7-day topical azole therapy.

Immediate Clinical Assessment

The burning sensation and vulvar swelling during nitrofurantoin treatment most likely represents:

• Vulvovaginal candidiasis (VVC), which presents with vulvar burning, pruritus, swelling, erythema, and possibly vaginal discharge 1
• Approximately 75% of women experience at least one episode of VVC, and pregnancy increases susceptibility 1
• Antibiotic therapy disrupts normal vaginal flora, predisposing to candidal overgrowth 1

Key diagnostic features to confirm:

• Vulvar erythema and edema with possible white discharge 1
• Pruritus (itching) as a predominant symptom 1
• External dysuria or dyspareunia if present 1

Treatment Approach

Continue UTI Treatment

Do not discontinue nitrofurantoin unless the UTI treatment course is complete:

• Nitrofurantoin remains first-line for UTI treatment during pregnancy 2
• The standard treatment course is 7 days for symptomatic UTI 2
• Untreated bacteriuria increases pyelonephritis risk 20-30 fold (from 1-4% to 20-35%) 2
• Treatment reduces premature delivery and low birth weight 2

Treat Vulvovaginal Candidiasis Concurrently

Only topical azole therapies are recommended during pregnancy:

• 7-day topical azole therapy is the only recommended treatment for VVC in pregnant women 1
• Short-course azole formulations used in non-pregnant women are NOT appropriate during pregnancy 1
• Options include clotrimazole, miconazole, or other topical azole preparations applied intravaginally for 7 consecutive days 1

Oral antifungals are contraindicated:

• Fluconazole and other oral azoles should not be used during pregnancy 1

Follow-Up Management

After Completing Nitrofurantoin Course

• Obtain follow-up urine culture 1-2 weeks after completing antibiotic treatment to confirm cure 2
• This is essential as recurrent UTIs are common during pregnancy 3, 4

If VVC Symptoms Persist

• Patients should return for follow-up only if symptoms persist or recur within 2 months 1
• Complicated VVC (recurrent, severe, or in immunocompromised patients) may require longer duration therapy 1

Consider Prophylaxis if Recurrent UTIs Develop

• For women with history of recurrent UTIs, postcoital prophylaxis with cephalexin (250 mg) or nitrofurantoin (50 mg) single dose is highly effective 3
• Prophylactic antibiotics may be considered for the remainder of pregnancy if recurrent UTIs occur 2

Critical Pitfalls to Avoid

Do not:

• Discontinue nitrofurantoin prematurely, as incomplete UTI treatment risks progression to pyelonephritis 2, 4
• Use short-course (1-3 day) topical azole regimens for VVC in pregnancy; only 7-day courses are appropriate 1
• Prescribe oral fluconazole or other systemic antifungals during pregnancy 1
• Assume the vulvar symptoms represent an allergic reaction to nitrofurantoin without considering VVC as the more likely diagnosis 1
• Treat asymptomatic bacteriuria repeatedly after initial treatment, as this fosters antimicrobial resistance 2

Do:

• Obtain urine culture before initiating any antibiotic therapy to guide treatment 2
• Screen for Group B Streptococcus if bacteriuria is present, as this requires intrapartum prophylaxis 2, 4
• Counsel the patient that VVC is a common, expected complication of antibiotic therapy during pregnancy and does not indicate treatment failure 1