Pollen-food allergy syndrome OSCE — oral itch triage and systemic-risk counselling

Station objectives

1. Triage a local oral reaction to a raw fruit and decide who is low-risk versus systemic-risk. [1]
2. Apply the fresh-food prick-prick test and component-resolved diagnostics appropriately. [4]
3. Counsel a family on the lipid-transfer-protein phenotype, adrenaline, and cofactors. [10]

Candidate brief

You are the paediatric doctor in an allergy clinic. Station A is 8 minutes (triage and dietary advice). Station B is 8 minutes (systemic-risk counselling). Examiners score safety prioritisation, evidence use, and partnership with families. [12] [13]

Station A — Triaging a local oral reaction

Setup: A nine-year-old with birch hayfever has had lip tingling, palate itch and throat tightness within a minute of a raw apple. She eats baked apple weekly without symptoms. The parent asks whether this is dangerous. [1]

Expected actions:

• Recognise pollen-food allergy syndrome: raw but not cooked, in a pollen-sensitised child; reaction confined to the oropharynx. [1]
• Confirm this is local-only and explicitly screen for systemic features (urticaria beyond the mouth, wheeze, abdominal pain, collapse). [12]
• Explain the heat-labile PR-10 mechanism so the family understands why cooked forms are tolerated. [4]
• Advise: avoid the raw apple, keep cooked and peeled forms, give a non-sedating oral antihistamine for breakthroughs, and do not over-restrict tolerated foods. [12]
• Arrange confirmation with pollen testing and the fresh-food prick-prick test plus component-resolved diagnostics; give a safety-net to return if any systemic symptom appears. [4]

Station B — Counselling the systemic-risk phenotype

Setup: A fourteen-year-old collapsed with generalised urticaria and wheeze minutes after a peach (skin on) at a picnic, having taken ibuprofen and gone for a run. The family asks what happened and what to do next. [10]

Expected actions:

• Explain this is anaphylaxis, not 'just oral allergy syndrome', driven by a heat-stable lipid transfer protein (Pru p 3), amplified by the ibuprofen and exercise cofactors. [10]
• Confirm the phenotype with component-resolved diagnostics (rPru p 3) and screen for cross-reactive LTP foods. [4]
• Prescribe two weight-banded adrenaline autoinjectors and a written anaphylaxis action plan (ASCIA/BSACI/FARE); train the adolescent, family and school. [13]
• Counsel on cofactor avoidance (NSAIDs, exercise after eating) and on avoiding peach in all forms, because LTP is heat-stable. [10]
• Arrange periodic review and consider specialist pollen immunotherapy referral. [4]

Marking anchors

Clear pass: correctly triages local versus systemic; explains the heat-labile mechanism; keeps cooked forms without over-restriction; for the LTP station prescribes adrenaline and an action plan and addresses cofactors. [1] [13] Borderline: identifies PFAS but cannot explain why cooked is tolerated; or counsels adrenaline but omits the NSAID and exercise cofactors in the LTP station. [10] [12] Fail: labels a systemic reaction 'mild OAS' and withholds adrenaline; or over-restricts tolerated cooked foods in the low-risk child; or fails to screen for systemic features. [12] [13]

Debrief pearls

• One question decides the pathway: is this local-only, or is there any systemic feature? [12]
• Raw not cooked, local not systemic — if both hold, it is low-risk PFAS and an antihistamine. [1]
• LTP is heat-stable: avoid the trigger in every form and prescribe adrenaline. [10]
• Ask about cofactors — exercise, NSAIDs, infection, alcohol — whenever a local reaction has gone systemic. [13]