GPAtlas🧭 When to suspect
A herpetic whitlow is a painful infection of a finger or thumb (occasionally a toe) caused by the herpes simplex virus (HSV) – the same virus that causes cold sores (HSV type 1) and genital herpes (HSV type 2). It usually affects the distal phalanx (fingertip), where the virus enters through a breach in the skin such as a torn cuticle.
Suspect it when a patient describes a prodrome of tingling, burning or itching in the digit, followed within a day or two by painful, clustered, fluid-filled vesicles (small blisters) on a red base. A personal or partner history of cold sores or genital herpes is common, and the blister fluid is typically clear rather than the frank pus of a bacterial infection.
It follows a bimodal age pattern: young children (autoinoculation from oral herpes, often through thumb-sucking) and adults aged 20–30 (genital herpes exposure, or occupational contact in healthcare and dental workers). It is uncommon – around 2.4 cases per 100,000 per year – which is precisely why it is so often misdiagnosed.
The single most important primary-care skill is to distinguish it from a bacterial felon or paronychia, because the management is opposite: a herpetic whitlow is treated conservatively and must never be incised, whereas a bacterial pulp-space abscess needs drainage.
| Feature | Herpetic whitlow | Bacterial felon / paronychia |
|---|---|---|
| Cause | HSV-1 or HSV-2 | Usually Staphylococcus aureus |
| Prodrome | Tingling, burning or itch before the rash | None |
| Lesion | Clustered clear vesicles on an erythematous base; may coalesce into bullae | Tense erythema with a localised collection of frank pus |
| Fingertip pulp | Soft and non-tense | Tense, throbbing, often fluctuant |
| Fluid | Clear (may later turn turbid or sero-purulent) | Frank pus |
| Key action | Conservative ± oral antiviral – never incise | Incision and drainage ± antibiotic |
Source: DermNet
🔒 Sign up free to read the full topic
You're viewing a free preview. Create a free account to unlock the rest.
Sign up free →Sample topics are open to everyone in the Free Sample Bundle.