Erysipelas

erysipelas · St Anthony's fire · superficial cellulitis

A more superficial infection than cellulitis, with an edge you can feel - almost always streptococcal.

GPBand C

Red flags

Facial erysipelas with eye involvement, proptosis or painful eye movements - orbital cellulitis needs urgent imaging and specialist referral
Pain out of proportion or rapid deterioration - necrotising infection
Systemic sepsis, which is commoner here than in ordinary cellulitis because of the rapid streptococcal onset
Recent chickenpox, or a concurrent scarlet fever outbreak - both raise the invasive group A streptococcal risk, and varicella is the commonest preceding event in children

Recognise

On light skin

Intensely red, shiny, raised plaque with a sharply defined, palpable advancing edge and a clear step down to normal skin, often with fever and rigors preceding it.

On brown and black skin

The intense redness that names the condition may be absent, and the affected skin may simply look darker, purple-brown or glossy. The defining feature is structural rather than chromatic: the edge is raised and you can feel the step from affected to unaffected skin. Run a fingertip across the margin from normal skin inwards. That palpable step is what separates erysipelas from cellulitis regardless of pigment, and it is more reliable than any colour description.

In any skin tone

A sharply demarcated, palpable, raised edge - the single discriminating sign from cellulitis
Rapid onset, often with fever and rigors before the skin changes
Shiny, tense, oedematous skin
Facial involvement is characteristic
Usually group A streptococcal

Distribution

Most often the face, classically over the cheeks and bridge of the nose in a butterfly pattern, or a lower limb. Sharply demarcated from surrounding skin.

Photographs

Erysipelas of the cheek and nose. The plaque is bright, raised and oedematous, and its edge is sharply demarcated - you could draw round it — Erysipelas of the cheek and nose. The plaque is bright, raised and oedematous, and its edge is **sharply demarcated - you could draw round it** - which is what separates erysipelas from cellulitis, where the border fades gradually into normal skin. The distinction is about the edge and the elevation, not the colour, so it still holds on skin where the erythema itself is hard to see. The only openly licensed photograph found for this entry shows light skin. **That is a limitation of this page, not of the disease** - a darker-skin photograph is still being sought.
Fitzpatrick II (Fitzpatrick type estimated from the photograph, not stated by the source) · CDC / Dr Thomas F. Sellers, Emory University; PHIL #2874 · Wikimedia Commons - Facial erysipelas.jpg · Public domain

Provenance for every photograph in this library: image licences. How much of the corpus still has no darker-skin photograph: skin tone coverage.

Mimics

Cellulitis — Deeper, with a diffuse poorly demarcated edge and no palpable step
Necrotising fasciitis and necrotising soft tissue infection — Also streptococcal and also rapid; disproportionate pain is the discriminator
Toxic shock syndrome — Streptococcal TSS can arise from the same organism and the same focus
Angio-oedema - allergic, ACE-inhibitor and hereditary — Facial swelling without fever, sharply raised but not hot or tender, is angio-oedema not erysipelas
Diabetic foot ulcer and deep-seated foot infection — A red hot foot in a person with diabetes goes down the NG19 pathway regardless of how sharply demarcated the edge looks

What to do in the ED

Treat as for cellulitis per NICE NG141 and local policy - NG141 treats cellulitis and erysipelas from the same table, with the same first choice, and flucloxacillin already covers group A streptococcus, so no additional penicillin is needed on that reasoning alone
Examine the eye carefully in any facial presentation and escalate for any orbital sign
Feel for the edge and document that it is raised and demarcated - this is the note that tells the next clinician what you actually found
Look for a portal of entry, which is often small: a fissure at the nostril, an ear piercing, a scratch
Lower threshold for admission than plain cellulitis when the face is involved or the onset has been abrupt with rigors
Elevate, give analgesia, and arrange early review

Disposition

Antibiotics with early planned review. Lower threshold for admission and intravenous therapy than for cellulitis, particularly with facial involvement or systemic upset.

Safety-netting

Return immediately if the eye becomes painful, swollen or the vision changes, if the area spreads beyond the marked edge, if the pain becomes severe, if the skin blisters or darkens, or if you develop a fever or feel very unwell. Seek review within 48 hours if there is no improvement.

Sources

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