Herpetic Whitlow

Definition

• Herpetic whitlow is a painful HSV infection affecting the fingers or thumbs, often arising from autoinoculation of the virus (commonly HSV-1 or HSV-2) from an existing oral or genital herpes lesion. It typically presents with vesicular or pustular lesions on the distal phalanx.

Aetiology

• Autoinoculation from existing oral/genital herpes (e.g. lip cold sores, genital sores)

• Direct inoculation from external sources (e.g. contact with someone else’s active HSV lesion)

• HSV-1 accounts for about 60% of cases, HSV-2 about 40%

Clinical Features

• Local Swelling, Itching, Burning: Prodromal sensation before vesicles appear

• Clear/Turbid Vesicles over the affected fingertip area, possibly crusting with time

• Prodromal Fever or Malaise may occur in more significant infections

• Lesions can be quite painful, leading to difficulty in using the affected finger

Differential Diagnosis

• Paronychia (infection of the nail fold, often bacterial)

• Hand-Foot-and-Mouth Disease (Coxsackie virus) – typically also with oral lesions and foot involvement

Management

• Antiviral Therapy (similar approach as for severe or complicated HSV infections):

  • Children ≥3 months: Aciclovir 10 mg/kg orally, five times daily for 5–7 days

  • Adults with moderate–severe herpetic whitlow: Aciclovir (e.g. 200 mg five times daily) or Valaciclovir (e.g. 1 g BD) for 5–7 days

• Pain Relief: Topical anaesthetics (e.g. lignocaine gel) or systemic analgesics (NSAIDs, paracetamol)

• General Care: Keep the area clean, cover with a light dressing if needed, avoid picking or squeezing vesicles to prevent secondary bacterial infection

Notes

• Prevent autoinoculation: Educate patients with cold sores/genital HSV to avoid touching lesions or to wear gloves if contact is unavoidable (e.g. healthcare workers).

• Consider that herpetic whitlow may recur if patients have recurrent HSV episodes.

• If infection is severe or complicated, or if immunocompromised, consult specialist advice or consider IV aciclovir.