Mastering Cellulitis & Erysipelas Management Guidelines for PLAB 2

Mastering Cellulitis and Erysipelas Management Guidelines for PLAB 2

Cellulitis and erysipelas are among the most common skin and soft tissue infections encountered in UK clinical practice, making them high-yield scenarios for the PLAB 2 OSCE examination. These stations test your ability to take a focused history, perform a basic examination, initiate correct guideline-based treatment, and, crucially, apply safety netting and appropriate referral criteria.

As an expert in UK clinical guidelines, here is a detailed guide to mastering the management of these infections for PLAB 2 success.

1. Differentiating Cellulitis and Erysipelas

While often managed similarly, knowing the key differences is a strong indicator of clinical acumen in the exam:

PLAB 2 Tip: Focus less on the exact differentiation and more on assessing severity and identifying systemic involvement, as management protocols largely align.

2. History and Assessment: Red Flags

The PLAB 2 scenario will require you to rapidly identify the severity of the infection. Use the history and examination to look for signs of systemic illness or deep-seated infection (necrotizing fasciitis).

Essential History Points:

1. Onset and progression: How quickly did it spread?

2. Systemic Symptoms: Fever, rigors, malaise (suggesting sepsis).

3. Risk Factors: Recent skin injury, insect bite, preceding fungal infection (e.g., athlete's foot), chronic oedema, lymphoedema, diabetes, peripheral vascular disease, immunosuppression.

4. Allergies: Crucial before prescribing.

**Immediate Red Flags (Indicating need for urgent admission):
**

• Systemic Toxicity: Fever >38.5°C, hypotension, confusion, tachycardia.

• Rapid Progression: Spreading quickly despite oral antibiotics.

• Severe Pain: Out of proportion to the clinical appearance (worrying for necrotizing fasciitis).

• Deep Tissue Signs: Bullae, skin necrosis, crepitus, purple discolouration.

• Immunosuppression: Chemotherapy, uncontrolled diabetes, concurrent use of steroids.

3. Management Guidelines: The Prescribing Station

Management is primarily antibiotic-based. UK guidelines (e.g., NICE) provide clear recommendations based on severity.

A. Uncomplicated Cellulitis (Non-severe/Mild)

These patients are managed in the community with oral antibiotics. This is the most common PLAB 2 prescribing scenario.

• First-line Choice: Flucloxacillin

  • Dose: 500 mg four times a day (QDS).

  • Duration: Typically 5 to 7 days. If slow response, consider extending to 10 days.

• Penicillin Allergy (Non-severe):

  • Clarithromycin (500mg BD) OR

  • Doxycycline (100mg OD) OR

  • Erythromycin (if pregnancy or children).

Adjunctive Management:

• Elevation: Elevate the affected limb to reduce oedema and pain.

• Analgesia: Advise paracetamol or ibuprofen.

• Manage Portals of Entry: Treat concurrent fungal infections (e.g., athlete’s foot) or fissures to prevent recurrence.

B. Complicated or Severe Cellulitis

If the patient meets any of the red flag criteria, they require immediate hospital admission for intravenous (IV) antibiotics.

• Admission Indication: Systemic signs, deep infection signs, failure of oral treatment, or significant comorbidity.

• Common IV Regimen: IV Flucloxacillin (or IV Clindamycin/Vancomycin if MRSA suspected or severe penicillin allergy).

PLAB 2 Action: If the patient is systemically unwell, your primary task is to explain the urgent need for admission, contact a senior clinician (e.g., Registrar), and initiate initial management (IV access, blood cultures, basic observations).

4. Communication and Safety Netting (The OSCE Core)

Excellent communication is essential, especially when dealing with infection where rapid deterioration is possible.

Key Communication Steps:

1. Explanation: Explain the diagnosis clearly (e.g., "This is a skin infection called cellulitis caused by bacteria that entered through a small break in the skin.").

2. Treatment Plan: Explain the need for antibiotics and the duration of treatment.

3. Safety Netting: This is non-negotiable for infection scenarios. Provide clear, explicit instructions on when to seek immediate medical attention.

Crucial Safety Netting Phrases for PLAB 2:

• "You need to come straight back to the Emergency Department if:"

  • The redness or swelling spreads rapidly.

  • You develop a high fever, shaking, or feel generally much worse.

  • The pain becomes severe or unmanageable.

  • You start feeling confused or faint.

• "If you haven't started improving within 48 hours of starting the antibiotics, please contact your GP or the clinic for reassessment."

5. Managing Recurrent Cellulitis

If the patient has two or more episodes of cellulitis in the same area (often the lower limb), consider discussing preventative measures. While not common in a 7-minute station, this shows excellent clinical breadth.

• NICE Recommendation: Referral to dermatology/specialist care may be needed.

• Prevention: Address underlying risk factors (e.g., chronic oedema, lymphoedema). Low-dose prophylactic penicillin may be considered in severe recurrent cases.

Mastering cellulitis management showcases your preparedness for common acute medical presentations, adherence to UK prescribing protocols, and ability to prioritize patient safety—all cornerstones of success in the PLAB 2 examination.