What is the best course of treatment for a patient presenting with mouth sores, considering potential causes such as herpes simplex virus or fungal infections?

Treatment of Mouth Sores

For mouth sores, begin with topical corticosteroids as first-line therapy—specifically betamethasone sodium phosphate 0.5 mg in 10 mL water as a rinse-and-spit solution four times daily—while simultaneously addressing the underlying cause through targeted antimicrobial therapy for herpes simplex virus or fungal infections. 1

Initial Assessment and Diagnostic Approach

Examine the oral cavity systematically, looking for:

• Distribution pattern: Localized lesions on keratinized mucosa (gingiva, hard palate) suggest recurrent herpes simplex virus, while diffuse involvement of non-keratinized mucosa suggests aphthous ulcers or other etiologies 2, 3
• Lesion morphology: Grouped vesicles on an erythematous base indicate HSV infection, while discrete round ulcers with yellow-gray pseudomembrane suggest aphthous ulcers 3
• Associated findings: Fever and gingivitis suggest primary HSV infection; lip crusting suggests herpes labialis 2, 4

Obtain oral and lip swabs if bacterial or candidal secondary infection is suspected, as slow healing may reflect HSV reactivation or superinfection 5

First-Line Topical Corticosteroid Therapy

For symptomatic relief and inflammation control:

• Betamethasone sodium phosphate 0.5 mg dissolved in 10 mL water as a 2-3 minute rinse-and-spit solution one to four times daily 1
• Clobetasol propionate 0.05% mixed in equal amounts with Orabase, applied directly to localized lesions on dried mucosa twice daily 5, 1
• Fluticasone propionate nasules diluted in 10 mL water twice daily as an alternative 1

The British Journal of Dermatology guidelines support topical corticosteroids for reducing oral inflammation across multiple blistering and ulcerative conditions 5

Cause-Specific Antimicrobial Therapy

For Herpes Simplex Virus Infection

Oral antiviral therapy is essential for HSV-related mouth sores:

• Acyclovir 400 mg orally five times daily for acute recurrent herpes labialis or intraoral HSV 6, 3
• Acyclovir 200-400 mg orally 2-5 times daily for suppressive therapy in patients with frequent recurrences (≥6 episodes per year) 6, 3
• Treatment is most effective when started within 48-72 hours of lesion onset 6

In immunocompromised patients, HSV can cause chronic destructive oral lesions requiring more aggressive and prolonged antiviral therapy 7, 8

For Candidal Infection

When fungal infection is confirmed or suspected:

• Nystatin oral suspension 100,000 units four times daily for 1 week 5, 1
• Miconazole oral gel 5-10 mL held in mouth after food four times daily for 1 week 5
• Fluconazole 100-200 mg orally once daily for oropharyngeal candidiasis, with 200 mg loading dose on day 1, continued for at least 2 weeks after symptom resolution 9

Supportive Care and Pain Management

Essential daily oral hygiene measures:

• Apply white soft paraffin ointment to lips every 2 hours throughout acute illness 5, 10, 11
• Clean mouth daily with warm saline mouthwashes using an oral sponge, sweeping gently in labial and buccal sulci to reduce bacterial colonization and prevent fibrotic scars 5
• Use mucoprotectant mouthwash (e.g., Gelclair) three times daily to protect ulcerated mucosal surfaces 5, 1

For pain control:

• Benzydamine hydrochloride oral rinse or spray every 3 hours, particularly before eating, provides anti-inflammatory and analgesic effects 5, 10, 11
• Viscous lidocaine 2%, 15 mL per application, held for 1-2 minutes before spitting, repeated every 3 hours as needed if benzydamine is inadequate 5, 10
• For severe oral discomfort, cocaine mouthwashes 2-5% three times daily may be considered 5

Antiseptic oral rinses twice daily to reduce bacterial colonization:

• 1.5% hydrogen peroxide mouthwash, 10 mL twice daily 5
• 0.2% chlorhexidine digluconate mouthwash, 10 mL twice daily (dilute by 50% if soreness occurs) 5

Second-Line Therapy for Recalcitrant Cases

When first-line topical corticosteroids fail:

• Tacrolimus 0.1% ointment applied twice daily for 4 weeks for recalcitrant oral lesions 5, 1, 10
• Intralesional triamcinolone (total dose 28 mg weekly) in conjunction with topical clobetasol for ulcers that don't resolve with topical treatment alone 1

The British Journal of Dermatology demonstrated that tacrolimus 0.1% ointment was beneficial in recalcitrant pemphigus vulgaris affecting the lips, with comparable efficacy to high-potency topical corticosteroids 5

Systemic Therapy for Severe or Highly Symptomatic Cases

Consider systemic corticosteroids when:

• Ulcers are highly symptomatic or recurrent despite topical therapy 1
• Prednisone/prednisolone 30-60 mg or 1 mg/kg orally for 1 week, followed by dose tapering over the second week 1

Critical Pitfalls to Avoid

• Never use alcohol-containing mouthwashes, as they cause additional pain and irritation 5, 10, 11
• Do not chronically use petroleum-based products alone on lips, as they promote mucosal dehydration and create an occlusive environment increasing secondary infection risk 5, 11
• Dilute chlorhexidine mouthwash by 50% if it causes excessive soreness 5
• Reevaluate diagnosis if no improvement after 2 weeks of appropriate treatment 11

Nutritional Support

If oral intake is severely compromised:

• Advise soft, moist, low-acidity foods 5
• Provide intravenous fluids if oral intake is inadequate 5
• Consider soft, fine-bore nasogastric tube for nutrition in severe cases 5