🩹 DermatologySkin / InfectiousStudentInternResident

Cellulitis

Also known as: skin infection · soft tissue infection · erysipelas

An acute bacterial infection of the skin and subcutaneous tissue — spreading redness, warmth, swelling and tenderness, usually of a lower limb. Streptococci and Staphylococcus aureus are the main organisms.

Source · Reviewed 2026-08-15 · v1.0— AI-assisted draft — verify against the cited guideline before clinical use.

⚕️ Education only — not medical advice. Verify against the latest official guideline and your local protocol; confirm every drug dose against the cited source before clinical use.

Who gets it

Anyone with a skin break (wound, tinea, ulcer, eczema); higher risk with oedema/lymphoedema, diabetes, obesity and venous insufficiency.

Red flags — escalate / refer

Rapidly spreading infection, pain out of proportion, crepitus, bullae or systemic toxicity → suspect necrotising fasciitis (surgical emergency).
Sepsis → escalate.

Work-up / diagnosis

1Mostly clinical; mark the border to track progression.
2Find and treat the entry point (e.g. tinea pedis, an ulcer).
3Bloods/cultures if systemically unwell; exclude DVT and other mimics.

Management — overview

Elevate the limb, treat any entry point, and manage oedema.
Oral antibiotics for mild–moderate infection (cover Streptococcus ± Staphylococcus); IV antibiotics if severe, systemic, or failing oral therapy.
Give analgesia; mark and review; look for and drain any abscess.
Necrotising infection → urgent surgery plus broad-spectrum antibiotics.

In-depthFull dosing & advanced protocol

Drug dosing

Oral antibiotic (mild–moderate)

Cover Strep ± Staph

Adult dose: e.g. flucloxacillin/cloxacillin or amoxicillin-clavulanate, per local guidance
Route: Oral

Caution: Consider MRSA cover per local prevalence; exclude necrotising fasciitis.

ICMRICMR Treatment Guidelines for Antimicrobial Use in Common Syndromes (2019) ↗

IV antibiotics (severe/systemic)

Severe or failing oral therapy

Adult dose: Per local antibiogram
Route: Intravenous

ICMRICMR Treatment Guidelines for Antimicrobial Use in Common Syndromes (2019) ↗

Mimics, MRSA & recurrence

Distinguish cellulitis from necrotising fasciitis, DVT and stasis dermatitis (bilateral, chronic).
Cover MRSA where prevalence is high or with risk factors.
Recurrent cellulitis: treat predisposing factors (tinea, oedema) and consider antibiotic prophylaxis.

ICMRICMR Treatment Guidelines for Antimicrobial Use in Common Syndromes (2019) ↗

References

Guidelines change. If something here is out of date, tell us — we keep these current.

🚩 Report outdated / suggest update

More protocols

ScabiesAn intensely itchy skin infestation by the mite Sarcoptes scabiei — worse at night, with burrows in the finger webs and flexures. Treat the patient AND all close contacts together.Atopic Dermatitis (Eczema)A chronic, itchy, relapsing inflammatory skin condition — dry skin with flexural involvement in children; part of the atopic triad (with asthma and allergic rhinitis). Managed by skin-barrier care and controlling flares.PsoriasisA chronic immune-mediated skin disease — well-demarcated, salmon-pink plaques with silvery scale, typically on extensor surfaces and the scalp. It is associated with psoriatic arthritis and cardiometabolic risk.

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👤 Who gets it

🚩 Red flags — escalate / refer

🔎 Work-up / diagnosis

🧭 Management — overview

💊 Drug dosing

Oral antibiotic (mild–moderate)

IV antibiotics (severe/systemic)

📈 Mimics, MRSA & recurrence

📚 References

More protocols

👤 Who gets it

🚩 Red flags — escalate / refer

🔎 Work-up / diagnosis

🧭 Management — overview

💊 Drug dosing

Oral antibiotic (mild–moderate)

IV antibiotics (severe/systemic)

📈 Mimics, MRSA & recurrence

📚 References

More protocols

Who gets it

Red flags — escalate / refer

Work-up / diagnosis

Management — overview

Drug dosing

Mimics, MRSA & recurrence

References

Who gets it

Red flags — escalate / refer

Work-up / diagnosis

Management — overview

Drug dosing

Mimics, MRSA & recurrence

References