Question
A 25 year old nurse has a throbbing, tense pulp of her index finger for three days after a needlestick injury.
- What is the diagnosis and why is the pain severe?
- How do you distinguish it from herpetic whitlow?
- Describe surgical drainage.
Answer
Diagnosis
- Felon, a closed space abscess of the digital pulp
- Fibrous septa run from skin to distal phalanx periosteum
- Rising pressure in these compartments causes severe pain
- Can cause pulp necrosis, osteomyelitis of the distal phalanx, septic DIP joint or flexor sheath infection
- Staphylococcus aureus most common
Herpetic whitlow
- Herpes simplex infection, common in healthcare workers
- Clear vesicles that coalesce, pulp is not tense
- Prodrome of burning pain
- Tzanck smear or PCR of vesicle fluid
- Do not incise, risk of bacterial superinfection and systemic spread
- Self limiting over 2 to 3 weeks, antivirals if early
Drainage
- Digital block and tourniquet
- Incise over the point of maximal fluctuance, often volar
- High lateral incision on the non contact side (ulnar for index to ring, radial for little finger and thumb)
- Avoid fish mouth incisions, they cause unstable painful pulp
- Divide septa and avoid the flexor sheath
- Pack, splint, antibiotics and review at 48 hours
- X-ray to look for osteomyelitis or a foreign body
Related pages
Author Contributions
Orthofracs team
Reviewed by Professor Phong Tran, Head of Orthopaedic Surgery, Western Health. Last updated 10 October 2026.