Whitlow (staphylococcal and herpetic)
Exam Tips
- Severe throbbing pain + tense distal pulp + no vesicles suggests staphylococcal felon; grouped vesicles + soft pulp + prodrome/recurrent episodes suggests herpetic whitlow.
- In OSCEs, explicitly state PPE/gloves before examining vesicular lesions to prevent HSV transmission.
- A fluctuant or tense bacterial whitlow needs urgent drainage consideration; delayed treatment risks osteomyelitis and tendon sheath spread.
- Classic viva pitfall: incision and drainage is appropriate for bacterial felon but contraindicated in herpetic whitlow.
- Ask about exposure history (oral/genital herpes, thumb-sucking, healthcare oral secretions, farm/bite injuries) to refine diagnosis.
- See Figure: clinical comparison table images in hand infection/dermatology texts showing felon versus herpetic vesicles for rapid pattern recognition.
Definition
Whitlow is an acute infection of the distal finger, most often affecting the pulp space (staphylococcal whitlow/felon) or the periungual-distal phalanx skin with grouped vesicles (herpetic whitlow). Staphylococcal whitlow is a closed-compartment bacterial infection, usually due to Staphylococcus aureus, whereas herpetic whitlow is caused by herpes simplex virus (commonly HSV-1, less often HSV-2) after inoculation through broken skin.
Pathophysiology
In staphylococcal whitlow, bacteria enter through a skin breach (cut, splinter, needlestick, or spread from paronychia) and multiply within the septated fingertip pulp. The digital pulp is divided by fibrous septa into small closed compartments, so inflammatory exudate raises pressure rapidly, causing severe throbbing pain and risking ischaemia, necrosis, and spread to tendon sheath, bone, or joint if delayed. In herpetic whitlow, HSV inoculates disrupted epidermis, replicates in epithelial cells to form painful vesicles, and then establishes latency in sensory ganglia; reactivation during stress/illness explains recurrence. See Figure: digital pulp septal anatomy in hand infection chapters (helps explain why felons are tense and exquisitely painful).
Risk Factors
- Penetrating fingertip trauma (cuts, splinters, bites, needlestick injuries)
- Frequent fingertip blood glucose testing (especially in diabetes)
- Untreated acute paronychia
- Diabetes mellitus, immunosuppression (e. g, HIV, systemic corticosteroids), or other causes of reduced host defence
- Exposure to oral/genital HSV lesions or secretions (including healthcare occupational exposure)
- Autoinoculation from herpes labialis, gingivostomatitis, or genital herpes
- History of MRSA colonization/infection (for resistant staphylococcal disease)
Clinical Features
Symptoms
- Staphylococcal: rapid onset severe throbbing fingertip pain, often after trauma or paronychia
- Herpetic: prodromal pain/paraesthesia for 1-3 days, then abrupt localized pain often out of proportion to early findings
- Herpetic: possible fever and malaise; recurrent episodes are common
- Both: swelling and tenderness at distal finger, usually thumb or index finger
Signs
- Staphylococcal: tense, erythematous, oedematous distal pulp (usually does not extend beyond DIP joint)
- Staphylococcal: fluctuant or boggy pulp when abscess forms; no true vesicles
- Herpetic: grouped clear vesicles (may become cloudy/bloody), soft pulp rather than tense pulp
- Herpetic: vesicles can ulcerate/crust; possible epitrochlear/axillary lymphadenopathy
- Evidence of entry wound or associated paronychia supports bacterial cause; absence of trauma with vesicles supports HSV
Investigations
Management
Lifestyle Modifications
- Elevate affected finger to reduce oedema and pain
- Warm moist compresses 3-4 times daily for comfort and to encourage drainage in bacterial disease
- Keep lesion clean, dry, and covered; avoid squeezing or puncturing at home
- Use gloves and strict hand hygiene to reduce HSV transmission and prevent ocular autoinoculation
- Safety-net: urgent review for worsening pain/swelling, fluctuation, spreading erythema/lymphangitis, fever, or recurrence
Pharmacological Treatment
Antistaphylococcal oral antibiotics (when no immediate I&D indication)
- Flucloxacillin 500 mg orally four times daily for 5-7 days (adult typical dose)
- If true penicillin allergy: Clarithromycin 500 mg orally twice daily for 5-7 days
- If pregnant or breastfeeding with penicillin allergy: Erythromycin 500 mg orally four times daily for 5-7 days
First-line is flucloxacillin for likely MSSA. Seek microbiology advice for known/suspected MRSA. Check allergy status carefully. Flucloxacillin: caution in hepatic impairment/history of cholestatic jaundice. Macrolides: major CYP interactions, QT prolongation risk; clarithromycin interacts with statins/warfarin.
Antiviral therapy for herpetic whitlow (selected cases)
- Aciclovir 200 mg orally five times daily for 5 days (commonly used off-label, best started early)
Most uncomplicated herpetic whitlow is self-limiting; consider antivirals for early presentation, severe pain, recurrent episodes, or immunocompromise. Adjust aciclovir dose in renal impairment; ensure hydration. Consider specialist input in pregnancy, neonates, or severe immunosuppression.
Analgesia
- Paracetamol 1 g orally every 4-6 hours as needed (max 4 g/day)
- Ibuprofen 400 mg orally up to three times daily with food if suitable
Avoid/limit NSAIDs in peptic ulcer disease, significant CKD, NSAID-sensitive asthma, anticoagulation risk, or late pregnancy.
Surgical / Interventional
- Same-day incision and drainage for tense or fluctuant staphylococcal whitlow (primary care only if trained and equipped; otherwise urgent surgical/ED referral)
- Urgent hospital admission and IV therapy if systemic toxicity, ascending lymphangitis, significant lymphadenopathy, or rapidly progressive infection
- Do NOT incise and drain herpetic whitlow (increases risk of secondary bacterial infection and delayed healing)
- Assess tetanus prophylaxis needs in penetrating injuries
Complications
- Flexor tenosynovitis
- Pulp compartment ischaemia and tissue necrosis
- Distal phalanx osteomyelitis
- Septic arthritis of adjacent joints
- Sinus tract formation and finger-pad scarring
- Rare systemic bacterial infection (more likely if delayed treatment or immunocompromise)
- Herpetic recurrence due to viral latency
- Ocular HSV spread from autoinoculation
- Persistent dysaesthesia/numbness between herpetic episodes
- Lymphangitis/lymphadenitis (notably with HSV-2), rarely hand/forearm lymphoedema
Prognosis
Outcomes are generally good with early, appropriate management. Staphylococcal whitlow usually resolves without sequelae if decompressed/treated promptly, while herpetic whitlow is commonly self-limiting over about 2-3 weeks but may recur because HSV remains latent in sensory ganglia.
Sources & References
✅NICE Guidelines(1)
- Whitlow (staphylococcal and herpetic)[overview]
📖Textbook References(8)
- Emergencies in - Obstetrics and Gynaecology, Second Edition (Stergios K. Doumouchtsis, S. Arulkumaran) (Z-Library).pdf(pp. 12, 13)[context]
- Oxford Handbook of Clinical Diagnosis (Huw Llewelyn, Hock Aun Ang, Keir Lewis etc.) (Z-Library).pdf(pp. 156)[context]
- Oxford Handbook of Clinical Diagnosis (Huw Llewelyn, Hock Aun Ang, Keir Lewis etc.) (Z-Library).pdf(pp. 680, 681, 682)[context]
- Oxford Handbook of Clinical Diagnosis (Huw Llewelyn, Hock Aun Ang, Keir Lewis etc.) (Z-Library).pdf(pp. 156)[context]
- Oxford Handbook of Clinical Diagnosis (Huw Llewelyn, Hock Aun Ang, Keir Lewis etc.) (Z-Library).pdf(pp. 680, 681)[context]
- Oxford Handbook of Clinical Diagnosis (Huw Llewelyn, Hock Aun Ang, Keir Lewis etc.) (Z-Library).pdf(pp. 155, 156)[context]
- [Oxford Medical Handbooks] Ian Wilkinson, Tim Raine, Kate Wiles, Anna Goodhart, Catriona Ha - Oxford Handbook of Clinical Medicine (2017, Oxford University Press) - libgen.li.pdf(pp. 419)[context]
- [Oxford Medical Handbooks] Ian Wilkinson, Tim Raine, Kate Wiles, Anna Goodhart, Catriona Ha - Oxford Handbook of Clinical Medicine (2017, Oxford University Press) - libgen.li.pdf(pp. 418, 419)[context]