Oral Herpes Simplex

Oral herpes simplex is infection of the mouth and perioral tissues by herpes simplex virus, mainly type 1, with primary infection presenting as gingivostomatitis and recurrence as intraoral or perioral vesicles. Most adults carry the virus latent in the trigeminal ganglion.

• Primary infection occurs in children aged 6 months to 5 years, and in young adults.
• Spread by saliva and direct contact, including from asymptomatic shedders.

Primary gingivostomatitis: fever, irritability, painful swollen bleeding gums, numerous vesicles that ulcerate on the gums, tongue, palate and lips, cervical lymphadenopathy, drooling, refusal to feed; lasts 7 to 14 days.

• Recurrent intraoral: clusters of small painful ulcers on keratinised mucosa (hard palate, gingiva), and perioral vesicles.
• Differential diagnosis: aphthous stomatitis, hand foot and mouth disease, herpangina, erythema multiforme, necrotising ulcerative gingivitis, Stevens Johnson syndrome, candidiasis, varicella, herpes zoster, pemphigus, Behcet disease.
• Complications: dehydration, eczema herpeticum, herpetic whitlow, keratitis, secondary bacterial infection, erythema multiforme, encephalitis (rare), widespread mucocutaneous disease in immunosuppression.

Clinical, with confirmation in atypical or severe illness.

• HSV PCR of vesicle fluid or swab (preferred), viral culture, direct fluorescent antibody.
• Full blood count, glucose, HIV test in recurrent, severe or prolonged disease.
• Biopsy for chronic ulcers in immunosuppression.

Hydration, pain control and early antivirals.

• Supportive: oral fluids in small frequent amounts (cold drinks, ice pops), soft bland diet, rest, avoid acidic foods, gentle oral hygiene with chlorhexidine 0.2 percent mouthwash, avoid kissing and sharing utensils, exclude from childcare during active lesions.
• Pharmacological: paracetamol 15 mg/kg every 6 hours (adults 1 g) and ibuprofen 10 mg/kg every 8 hours (adults 400 mg three times daily); lidocaine 2 percent viscous gel or benzydamine 0.15 percent mouthwash for pain; aciclovir 200 mg five times daily for 5 days (children aged 2 years and over; under 2 years 100 mg five times daily), or valaciclovir 1 g twice daily for 7 days in adults, started within 72 hours. Severe or immunocompromised: aciclovir 5 mg/kg IV every 8 hours until improved then oral therapy to complete 7 to 10 days. Suppression for frequent recurrence: aciclovir 400 mg twice daily or valaciclovir 500 mg daily.
• Procedures: IV fluids for refusal to drink; nasogastric feeding if severe.
• Special groups: pregnancy, aciclovir or valaciclovir are acceptable; infants, urgent paediatric review for dehydration; HIV, longer treatment; renal impairment, adjust dose.
• Red flags: inability to drink, lethargy, eye involvement, widespread skin vesicles, immunosuppression, neonatal disease, fever beyond 5 days.
• Follow-up: review at 2 to 3 days in children; ulcers heal in 2 weeks; recheck if lesion persists beyond 3 weeks.