History Taking · Intermediate · Dermatology

Sudden Onset Itchy Rash All Over Body

Practise this PLAB 2 history taking station on Acute Urticaria. 8-minute voice AI simulation with feedback on all 3 marking domains.

Clinical scenario

You are an FY2 doctor in a GP surgery. Mr Rohan Sheikh, a 42-year-old man, has come to see you with a sudden onset rash all over his body that is intensely itchy. The rash appeared this morning and is causing significant discomfort. He is worried about what has caused it and wants urgent relief from the itching. Please take a focused history and examine the patient, then discuss your assessment and management plan.

Background notes: PMH: Hay fever (seasonal), appendectomy age 20

What this station tests

  • Excluding anaphylaxis as the first priority: airway, breathing, circulation assessment before detailed history
  • Identifying the trigger: shellfish, new medications (NSAIDs, antibiotics), infections, and new products
  • Screening for angioedema: lip, tongue, and eyelid swelling coexists in 40% and indicates greater severity
  • Non-sedating antihistamine as first-line: cetirizine or loratadine, with uptitration option
  • Anaphylaxis safety netting: throat swelling, breathing difficulty, dizziness require 999

How to use your 8 minutes

  • 0-1 min — Introduction: Introduce yourself, confirm identity, open question. 'What's brought you in today?'
  • 1-4 min — Systematic History: Presenting complaint detail (SOCRATES for pain, timeline, severity). Systems review. PMH, medications, allergies.
  • 4-6 min — Context and ICE: Social history (smoking, alcohol, occupation, living situation). Family history. Ideas, Concerns, Expectations.
  • 6-7 min — Summary and Plan: Summarise findings back to patient. Share differential/working diagnosis. Outline investigation and management plan.
  • 7-8 min — Closing: Safety netting with specific red flags. Arrange follow-up. Check for questions.

Consultation approach

The opening

Acute urticaria requires the candidate to identify the trigger, exclude anaphylaxis, and provide effective treatment. The candidate must also distinguish urticaria from more serious rashes. Mr Sheikh is 42, presenting with sudden-onset intensely itchy wheals all over his body since this morning. Open with: 'Mr Sheikh, this rash looks very uncomfortable. Tell me when it appeared and what you were doing beforehand.'

Core approach

Confirm urticaria. Raised, red, itchy wheals that blanch with pressure. Individual wheals are transient (lasting <24 hours, though new ones keep appearing). Intensely pruritic. No blistering, no bruising, no mucosal involvement. This is classic acute urticaria.

Exclude anaphylaxis immediately. Any difficulty breathing, wheeze, throat swelling, tongue swelling, dizziness, or feeling faint? Any voice changes? No. He is haemodynamically stable. This exclusion must be done before proceeding with the history.

Identify the trigger. He ate shellfish at dinner last night (plausible trigger, 6 to 12 hour onset is typical for food-related urticaria). Any new medications in the past 48 hours? (NSAIDs and antibiotics are common triggers.) Any new washing powder, cosmetics, or skin products? Recent infection? (Viral infections can trigger urticaria.) He has hay fever (atopic predisposition). Check if he has had shellfish before without reaction (first-time reactions can occur after previous tolerant exposures).

Screen for angioedema (deeper swelling). Any lip, tongue, or eyelid swelling? Angioedema coexists in 40% of urticaria cases and indicates more significant allergic response.

Closing and safety netting

Treatment: non-sedating antihistamine (cetirizine 10mg or loratadine 10mg). If standard dose insufficient, can be uptitrated to up to 4 times the standard dose per specialist advice. If severe: short course of prednisolone (40mg for 3 days). Avoid the suspected trigger (shellfish) until allergy testing can clarify.

Allergy referral: if this is a first episode with a clear food trigger, referral for specific IgE testing or skin prick testing can confirm the allergy and guide avoidance. Provide written allergy action plan if anaphylaxis risk is identified. Consider prescribing an adrenaline auto-injector if angioedema was present or if anaphylaxis risk is significant.

Safety net: 'If you develop any swelling of your lips, tongue, or throat, difficulty breathing, or feel dizzy or faint, call 999 immediately as this would be a severe allergic reaction.' Follow-up in 1 week if symptoms persist (>6 weeks becomes chronic urticaria, different investigation pathway).

How examiners mark this station

Examiners will focus on the thoroughness and structure of your history taking for acute urticaria. Domain 1 (Data Gathering) carries the most weight: expect marks for systematic coverage of presenting complaint, red flags, PMH, medications, social and family history. Domain 2 (Clinical Management) requires a clear differential, appropriate investigations, and a safe management plan with safety netting. Domain 3 (Interpersonal Skills) is assessed throughout: genuine exploration of ICE, active listening, empathic responses, and clear communication without jargon.

Domain 1: Data Gathering, Technical and Assessment Skills (Primary focus)

Scores well: Anaphylaxis excluded first. Urticaria confirmed (transient wheals, blanching). Trigger identified (shellfish). Angioedema screened. Atopic background noted. Medication review.

Costs marks: Not excluding anaphylaxis. Not identifying trigger. Not screening for angioedema.

Domain 2: Clinical Management Skills (Primary focus)

Scores well: Non-sedating antihistamine prescribed. Prednisolone for severe cases. Trigger avoidance advised. Allergy referral arranged. Anaphylaxis safety netting with 999 instruction. Adrenaline auto-injector considered.

Costs marks: Sedating antihistamine. No trigger avoidance. No allergy referral. No anaphylaxis safety netting.

Domain 3: Interpersonal Skills (Throughout)

Scores well: Acknowledging how uncomfortable the itching is. Explaining the likely trigger clearly. Providing a practical avoidance plan. Clear, memorable safety netting.

Costs marks: Dismissing the severity. Being vague about trigger. Not providing actionable safety netting.

Common examiner feedback (and how to fix it)

Did not gather sufficient information to make an adequate assessment of the patient's condition

Fix: Use a consistent framework for every history. After covering the presenting complaint, systematically move through PMH, drug history, social history, family history, and ICE. Keep a mental checklist.

Did not identify the patient's problems and/or did not develop a management plan adequately

Fix: Reserve the final 2 minutes to summarise your findings, share your working diagnosis with the patient, and outline your investigation and management plan including safety netting.

Common mistakes in this station

  1. Not excluding anaphylaxis before taking a detailed history. Urticaria can be the first sign of anaphylaxis. Candidates who take a full allergy history without checking for airway compromise, breathing difficulty, or haemodynamic instability miss a potentially life-threatening presentation.
  2. Prescribing sedating antihistamines. Chlorpheniramine is sedating and should not be first-line. Non-sedating options (cetirizine, loratadine, fexofenadine) are preferred. Candidates who prescribe sedating antihistamines demonstrate outdated practice.
  3. Not arranging allergy follow-up. A first episode of urticaria with a clear food trigger should prompt allergy testing to confirm the trigger and guide future avoidance. Candidates who treat and discharge without follow-up miss the prevention step.

Resitting PLAB 2?

If you have previously struggled with history taking stations, focus on building a consistent systematic framework that you apply to every case. Practise structuring your history into clear phases (presenting complaint, systems review, PMH, social, ICE) so that even under pressure, you cover all domains. Many resitters lose marks not on knowledge but on organisation and time management.

Example opening

Good morning/afternoon, my name is Dr [Name], I'm one of the doctors here today. Could I confirm your name and date of birth please? Thank you. So, what's brought you in to see me today?

Frequently asked questions

What is the best way to take an acute urticaria history in PLAB 2?

Acute urticaria requires the candidate to identify the trigger, exclude anaphylaxis, and provide effective treatment. The candidate must also distinguish urticaria from more serious rashes. Mr Sheikh is 42, presenting with sudden-onset intensely itchy wheals all over his body since this morning.

Where are marks won and lost in this acute urticaria station?

Examiners reward: Anaphylaxis excluded first. Urticaria confirmed (transient wheals, blanching). Trigger identified (shellfish). Angioedema screened. Atopic background noted. Medication review. Candidates are penalised for: Not excluding anaphylaxis. Not identifying trigger. Not screening for angioedema.

Where do candidates most often go wrong in this station?

Not excluding anaphylaxis before taking a detailed history. Urticaria can be the first sign of anaphylaxis. Candidates who take a full allergy history without checking for airway compromise, breathing difficulty, or haemodynamic instability miss a potentially life-threatening presentation.

Can I do well in this station without real-world experience of acute urticaria?

Structure beats experience here. Focus on identifying the trigger: shellfish, new medications (NSAIDs, antibiotics), infections, and new products. Use the domain breakdown on this page to target your preparation, then practise the station aloud so your structure survives exam pressure.

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