Derm Cases · Dermatology / Infectious Diseases / Emergency Medicine
OSCE — lower-limb cellulitis vs erysipelas and necrotising red flags
An 8-minute OSCE station on distinguishing cellulitis from erysipelas and pseudocellulitis, identifying necrotising infection red flags, portal-of-entry care, antibiotic selection, and disposition.
On this page
Study tools
Target exams
NEET-PGINICETUSMLEPLABMRCP
Prompt
An 8-minute OSCE station on distinguishing cellulitis from erysipelas and pseudocellulitis, identifying necrotising infection red flags, portal-of-entry care, antibiotic selection, and disposition.
Brief (to candidate)
A 62-year-old woman with tinea pedis and mild lymphoedema presents with 36 hours of fever, unilateral leg erythema, warmth and pain. The leading edge is well demarcated on the shin with peau d’orange change. There is no crepitus. You have 8 minutes to diagnose, exclude necrotising infection, treat and prevent recurrence.
[5]Candidate instructions
- Distinguish erysipelas vs cellulitis and common pseudocellulitis mimics.
- Screen for necrotising soft-tissue infection red flags.
- Identify portal of entry and host risks.
- Choose empiric antibiotics and disposition (OP vs IV/admit).
- Plan supportive care and recurrence prevention.
- Safety-net for deterioration.
Examiner checklist (mark each domain / 10)
| Domain | Key actions expected |
|---|---|
| Recognition | Acute unilateral dermal infection; erysipelas: superficial, sharply demarcated, often streptococcal; cellulitis: deeper dermis/subcutis, less sharp border — this case fits erysipelas/cellulitis spectrum[1][2] |
| Mimics | Considers DVT, stasis dermatitis, lipodermatosclerosis, contact dermatitis, gout, haematoma (pseudocellulitis) before unnecessary prolonged antibiotics[3] |
| Red flags | Pain out of proportion, rapid spread, bullae, crepitus, anaesthesia, systemic toxicity → necrotising fasciitis surgical emergency; do not delay for imaging alone |
| Portal & risks | Treats tinea pedis, interdigital maceration, lymphoedema, diabetes, prior episodes; blood cultures mainly if septic/immunocompromised |
| Antibiotics | Empiric cover streptococci ± MSSA per local guidance (e.g. flucloxacillin/cefalexin class agents where appropriate); escalate for MRSA risk, bite, water exposure, or severe sepsis; mark border, elevate limb, analgesia[4] |
| Disposition | IV/admit if sepsis, rapid progression, failed oral Rx, severe comorbidity, or inability to monitor; otherwise ambulatory pathway with early review |
| Prevention | Skin care, treat tinea, compression for lymphoedema when infection controlled; discuss prophylaxis only after recurrent confirmed episodes |
Model key actions
- Diagnose acute erysipelas/cellulitis, not bilateral stasis dermatitis.[1]
- Exclude necrotising infection; start timely antibiotics + elevation; treat tinea portal.[2][4]
- Avoid over-calling infection when pseudocellulitis features dominate.[3]
Common errors
- Missing necrotising fasciitis red flags.
- Treating bilateral venous stasis as bilateral cellulitis.
- Ignoring tinea pedis / lymphoedema portal.
- Routine imaging/blood cultures in uncomplicated cases without indication.
- No safety-net for 24–48 h deterioration.
References5ShowHide
- [1]Raff AB, Kroshinsky D. Cellulitis: A Review. JAMA, 2016.PMID 27434444
- [2]Rrapi R, Chand S, Kroshinsky D. Cellulitis: A Review of Pathogenesis, Diagnosis, and Management. The Medical Clinics of North America, 2021.PMID 34059247
- [3]Boettler MA, Kaffenberger BH, Chung CG. Cellulitis: A Review of Current Practice Guidelines and Differentiation from Pseudocellulitis. American Journal of Clinical Dermatology, 2022.PMID 34902109
- [4]Long B, Gottlieb M. Diagnosis and Management of Cellulitis and Abscess in the Emergency Department Setting. The Journal of Emergency Medicine, 2022.PMID 34657784
- [5]Peghin M, Graziano E, Rovelli C, et al. Prevention and treatment of recurrent cellulitis Curr Opin Infect Dis, 2023.PMID 36853755