Cellulitis and Erysipelas
NICE guideline [NG141] Cellulitis and erysipelas: antimicrobial prescribing. Published: Sep 2019.
NICE CKS Cellulitis – acute. Last revised: Nov 2024.
Background Information
Definition
Cellulitis: deep skin infection, involving the dermis and subcutaneous tissue
Erysipelas: superficial skin infection, involving only the upper dermis
Causative Agent
Most common causative agents:
- Cellulitis: Staphylococcus aureus, Group A strep (Streptococcus pyogenes)
- Erysipelas: Group A strep (Streptococcus pyogenes)
Guidelines
Assessment
Cellulitis and erysipelas are clinical diagnoses.
Only consider taking a swab for microbiology to guideline treatment if:
- Skin is broken, and
- Penetrating injury / exposure to water-borne organisms / infection acquired outside the UK
Severity Classification
Eron classification system:
| Eron Class | Description |
|---|---|
| I |
|
| II |
|
| III |
|
| IV |
|
Management
Admission Criteria
Essentially, Eron class II – IV requires hospital referral (see above), and
- Severely immunocompromised patients
- Other serious conditions
- Septic arthritis
- Osteomyelitis
- Orbital cellulitis
Base urgency on clinical judgement, for instance it is sensible to refer immediately to emergency department in Eron class IV.
Antibiotic Therapy
Consider drawing around the extent of the infection (edge of the redness) with a surgical marker pen to monitor progress.
Route of administration:
- 1st line: oral antibiotics
- If cannot tolerate oral medications / severely unwell → IV antibiotics
Standard choice of antibiotics in adults (>18 y/o):
- 1st line: flucloxacillin (5-7 days)
- 2nd line: clarithromycin / erythromycin / doxycycline
See below for the choice of antibiotics in various scenarios and patient populations:
Infection Near the Eyes / Nose
- 1st line: co-amoxiclav
- 2nd line: clarithromycin + metronidazole
Severe Infection
Any of the following
- Co-amoxiclav
- Cefuroxime
- Clindamycin
- Ceftriaxone (only IV route available)
MRSA Infection Suspected / Confirmed
Give 1 of the following + a standard antibiotic (see above):
- Vancomycin
- Teicoplanin
- Linezolid
Young People (<18 y/o)
Essentially same as above, but doxycycline should not be used:
- 1st choice antibiotic is still flucloxacillin
- Same antibiotics in other situations (apart from no doxycycline)
Pregnancy
- 1st line: flucloxacillin (penicillin is safe during pregnancy)
- 2nd line: erythromycin (preferred over clarithromycin and doxycycline)
References
Original Guideline