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Paronychia
The infected nail fold — drain the pus, think about the flexor sheath.
| If you find… | …then |
|---|---|
| Kanavel signs (fusiform swelling, flexed posture, sheath tenderness, pain on passive extension) | Flexor sheath infection — hand surgeons today |
| Pulp space infection (felon) | Hand surgery |
| Diabetic / immunosuppressed with spreading infection | Lower threshold for antibiotics / referral |
| Recurrent / chronic | Consider candida, dermatitis |
- Onset, nail biting, manicure, hangnail
- Diabetes, immunosuppression
- Pain on finger movement
- Red swollen nail fold, visible pus collection
- Whole finger: pulp, flexor sheath, Kanavel signs
- Lymphangitis
Draining a paronychia
After a digital block, slide a 21G needle or the flat of a scalpel blade between the nail fold and the nail plate at the point of maximum swelling, and lift the fold to release pus. No skin incision is usually needed.
Kanavel’s four signs
Finger held in slight flexion, fusiform (sausage) swelling, tenderness along the flexor sheath, and severe pain on passive extension. Any of these makes it a surgical emergency.
Kanavel signs
- Fusiform swelling of the whole finger
- Finger held flexed
- Tenderness along the flexor sheath
- Pain on passive extension
Any present: Kanavel positive → flexor sheath infection: hand surgery today. None present: Localised paronychia → drain in clinic.
| Investigation | Only if… |
|---|---|
| None | Swab if recurrent or not responding |
Management & advice
- No pus: warm soaks 3–4 times a day for 15 min
- Pus: drain — lift the nail fold away from the nail with a blade/needle (digital block if needed)
- Keep clean and dry; dressing
Refer / follow-up
- Flexor sheath infection, felon, failed drainage → hand surgery
| Drug | Dose | Duration / notes |
|---|---|---|
| Flucloxacillin (if cellulitis spreading beyond the nail fold, or high risk) BNF ↗ | 500 mg four times a day | 5–7 days |
| Penicillin allergy: clarithromycin BNF ↗ | 500 mg twice a day | 5–7 days |
| Paracetamol BNF ↗ | 1 g every 4–6 hours, max 4 g in 24 h (reduce if under 50 kg or liver risk) | As needed |
This is an infection next to the nail. Letting the pus out is the main treatment. Soak it in warm water a few times a day and keep it clean. Come back the same day if the whole finger swells up, it hurts to straighten it, or you see red lines spreading up your hand.
Come back / call 111 — or 999 if severe — if:
- Whole finger becomes swollen, or it hurts to straighten it
- Red streaks up the hand/arm, fever
- Not improving in 48 h
Official NHS pages. Ask the patient to scan the code with their phone camera, or tap “Show to patient” to make it full screen.
There’s no dedicated NHS page; the NHS skin abscess page covers the basics.
- Antibiotics without draining the pus
- Missing flexor sheath infection
- Missing herpetic whitlow (vesicles — don’t incise)
Revision practice. Work through a real or imagined case to rehearse the reasoning. It builds a model note to learn from. It doesn’t replace your judgement, your seniors or local guidance.
✎Blank clinic note template
Paronychia — clinic note
Doses are typical doses drawn from the guidance above. Always confirm in the current BNF/BNFc and your local antimicrobial policy.