HSV (Herpes Simplex Virus)

• Common viral infection caused by HSV-1 (oral-labial lesions, herpetic whitlow) or HSV-2 (often genital, but can infect other sites)

• Primary infection typically more symptomatic than recurrences

• Transmitted via direct contact with lesion fluid or mucosal secretions

Oral HSV (Herpetic Gingivostomatitis)

• Often due to HSV-1

• Affects oral mucosa, gums, lips, inside of the mouth

• Presentation: painful vesicles or ulcers, gingivitis, possible fever, malaise

• Risk of dehydration in children if oral intake is reduced due to pain

Herpetic Whitlow (Finger Infection)

• Caused by HSV-1 or HSV-2 through direct contact with infected oral or genital lesions

• Infection of the fingertip or nail bed

• Risk factors: healthcare workers (dentists), children with thumb-sucking habit, immunocompromised patients

• Presents with painful vesicles or ulcers on the finger, local swelling and erythema

Diagnosis

• Primary Infection

  • PCR swab from lesion is the gold standard for confirmation

  • Direct fluorescent antibody (DFA) testing can be used if PCR unavailable

  • Tzanck smear is outdated (reveals multinucleated giant cells but lacks specificity)

• Recurrent Lesions

  • Usually diagnosed clinically, lesions recur in the same site

  • Serological tests (HSV IgG/IgM) may help distinguish HSV-1 vs HSV-2, though not routinely required

Management

• Primary HSV Infection

  • If mild: supportive care with topical anaesthetic gel or mouthwash, regular analgesia, adequate hydration

  • If severe or extensive lesions: oral antivirals (e.g. valaciclovir 1 g BD for 7 days)

  • Consider IV antivirals in severe immunocompromise or disseminated infection

• Recurrent HSV Infection

  • If mild or limited: topical aciclovir 5% cream q4h for 5 days or one-off oral therapy (famciclovir 1.5 g stat)

  • If severe or frequent: oral famciclovir 1.5 g stat can shorten the episode

  • Suppressive therapy with valaciclovir 500 mg daily for ≥6 months if recurrent episodes are frequent or complicated (e.g. erythema multiforme)

  • Early initiation during the prodromal phase (tingling or burning) significantly reduces lesion severity and duration

• Herpetic Whitlow

  • Oral antiviral (valaciclovir or famciclovir) if pain or extensive involvement

  • Keep lesion covered, practise meticulous hand hygiene

  • In immunocompromised individuals, consider longer antiviral courses

• Non-Pharmacological Measures

  • Avoid direct contact with active lesions (no sharing utensils, lip balms)

  • Identify triggers for recurrent flares (trauma, UV exposure, stress, immunosuppression)

  • Emphasise hand washing to prevent autoinoculation (e.g. from lip to finger or eye)

  • Advise patients to watch for ocular involvement (urgent ophthalmology referral if suspected)

Complications

• Local

  • Secondary bacterial infection of lesions

  • Severe pain or dehydration if lesions in oropharynx

• Neurological

  • Encephalitis (HSV is the most common sporadic encephalitis cause)

  • Aseptic meningitis

  • Bell’s palsy (rare)

• Haematological or Mucocutaneous

  • Erythema multiforme triggered by HSV

• Other

  • Disseminated infection in immunocompromised hosts

Notes:

• Early recognition of primary infection can prompt timely antiviral therapy and reduce complications

• Recurrent cold sores are very common, and patient education on prodromal symptoms plus early antiviral use is crucial

• Herpetic whitlow in healthcare workers emphasises need for gloves and protection

• Children with gingivostomatitis may require careful hydration management

• Investigate severe or atypical presentations for immunodeficiency or other underlying pathologies