Diagnosis
- Clinical: painful, tender, fluctuant swelling, often with surrounding erythema; fluctuance can be subtle in early or deep collections.
- Point-of-care ultrasound is useful when fluctuance is equivocal — confirms a hypoechoic fluid collection, distinguishes abscess from cellulitis alone, and helps plan the incision.
- Assess for systemic illness (fever, tachycardia, spreading cellulitis) and risk factors (diabetes, immunosuppression, IV drug use, recurrent abscesses).
Sites needing referral rather than ED drainage
Usually refer
- Deep or complex perianal abscess
- Breast abscess (especially lactational — ultrasound-guided aspiration often preferred)
- Deep neck space collections
- Hand — especially palmar space or flexor sheath
Refer or discuss
- Central facial abscess (danger triangle)
- Bartholin's abscess (gynaecology)
- Pilonidal abscess (per local surgical policy)
Simple, accessible limb/trunk abscesses in well patients are the core ED-appropriate group; anything deep, near named structures, or in a high-risk site should follow local referral pathways.
Anaesthesia
- Local anaesthetic works poorly in infected, acidic tissue — infiltrating directly into pus rarely gives good analgesia.
- Infiltrate the planned incision line ("roof") and surrounding field generously, aiming to block the field around rather than relying on direct infiltration of the abscess cavity.
- For large, deep, or very painful abscesses (or in children), consider procedural sedation or a regional block rather than local alone.
Technique
Incise along skin tension lines
Make the incision over the point of maximal fluctuance, orientated along natural skin tension lines where possible for a better cosmetic result.
Adequate length
Incise wide enough to allow full evacuation and finger/instrument access — an incision that is too small under-drains the cavity.
Break loculations
Use blunt dissection (finger or artery forceps) to break down septae/loculations within the cavity so all pockets of pus are evacuated.
Irrigate
Irrigate the cavity with saline until the effluent runs clear.
Decide on packing
See the packing debate below — pack loosely if used, do not overpack.
The packing debate
Routine deep wound packing after adequate drainage is traditional practice, but the evidence base for it is weak:
- Trials comparing packing vs no packing after I&D generally show no significant difference in healing time, recurrence or need for further intervention, but packing is associated with more pain at dressing changes.
- A reasonable balanced approach: pack larger or deep cavities loosely for haemostasis/to keep the wound open for continued drainage; avoid packing small, well-drained cavities.
- Whichever approach is used, arrange follow-up for dressing change/pack removal and wound check.
Antibiotics
- Antibiotics are not routinely required after adequate incision and drainage of a simple abscess in an otherwise healthy patient — drainage is the primary treatment.
- Adjunctive antibiotics (particularly MRSA-active agents) modestly improve cure rates and reduce recurrence in some trial populations, so shared decision-making has a role.
- Consider antibiotics when there is surrounding cellulitis, systemic signs of infection, immunocompromise, extremes of age, comorbidity (e.g. diabetes), or a high-risk site (central face, near prosthetic material).
Safety-netting & documentation
- Advise on signs of worsening infection and when to return; arrange dressing change/review as needed.
- Document fluctuance/ultrasound findings, anaesthesia given, incision site and length, loculations broken down, irrigation, packing decision, antibiotics decision and follow-up plan.
Supervision pointers
Generic ED skills entrustment levels — not a named curriculum DOPS:
| 1 | Observed only — describes indications, anaesthesia challenges and referral thresholds. |
| 2a | Performs simple I&D with supervisor scrubbed alongside; achieves adequate field anaesthesia and breaks down loculations. |
| 2b | Performs with supervisor in department; makes reasoned packing/antibiotic decisions. |
| 3 | Indirect supervision; recognises abscesses needing referral and manages complications. |
| 4 | Independent; teaches technique and supervises trainees. |
References
- Wang W, et al. Antibiotics for uncomplemented skin abscesses after incision and drainage: a BMJ Rapid Recommendation. BMJ 2018 / summarised Am Fam Physician 2018;98(5):323-324.
- Adding antibiotics for abscess management — meta-analysis discussion. PMC 2019.
- Post-operative antibiotics for cutaneous abscess after incision and drainage: variations in clinical practice. PMC 2022.