Short answer: Suspect anaphylaxis when a sudden reaction causes airway, breathing or circulation problems, often with skin changes after an exposure. Call for help and give intramuscular adrenaline into the outer thigh without delay. Then lay the patient flat, give oxygen, and start fluids if needed. Antihistamines and steroids are not the first drugs.
What it is and how to spot it
Anaphylaxis is a severe, sudden allergic reaction. The Resuscitation Council UK describes it as a life-threatening problem with airway, breathing or circulation, usually with skin or mucosal changes, after exposure to a likely trigger. Skin changes may be missing, so do not wait for a rash if the rest fits.
This is exam-preparation revision, not clinical guidance. In practice, follow your own organisation’s policies and the current guideline, and check doses and thresholds against them.
- Airway: swelling of the lips, tongue or throat, hoarse voice, stridor.
- Breathing: wheeze, breathlessness, fast breathing, low oxygen saturation.
- Circulation: low blood pressure, fast pulse, pallor, collapse.
- Skin: hives, flushing, itching, swelling.
- Triggers: drugs, foods, insect stings, latex, contrast media.
Adrenaline first
Intramuscular adrenaline is the first-line drug. For adults and children over 12, Resuscitation Council UK guidance gives 500 micrograms, which is 0.5 mL of the 1 mg per mL (1 in 1000) solution, into the outer part of the middle third of the thigh. If there is no improvement, product labelling and guidance describe repeating after about 5 minutes. Doses for younger children are banded by age or weight, so read the chart your organisation uses.
Intravenous adrenaline is limited to experienced specialists in an appropriate setting. Exam questions often include it as a tempting wrong option for a ward nurse.
The sequence around the adrenaline
Exams usually reward this order.
- Call for help and note the time. Stop or remove the trigger if you can, such as the infusion, without delaying treatment.
- Give intramuscular adrenaline.
- Lay the patient flat with the legs raised. If breathing is difficult, let them sit up. If pregnant, lay them on the left side. Do not let a collapsed patient stand.
- Give high-flow oxygen.
- Start intravenous fluids if the patient is hypotensive, as directed.
- Monitor airway, breathing and circulation continuously until the team arrives.
After the emergency
Patients are observed for a recurrence, because symptoms can return after the first episode. Your local protocol sets how long. Mast cell tryptase blood tests, specialist allergy referral, documentation of the trigger and advice on carrying adrenaline are typical follow-up steps. Report the event as your policy requires.
Common exam traps
Look out for these wrong options.
- Giving an antihistamine first. These help skin symptoms, but they do not treat the airway or circulation problem.
- Waiting for a doctor before giving adrenaline when your policy allows you to give it.
- Choosing intravenous adrenaline instead of intramuscular for a ward nurse.
- Leaving the patient to sit up or walk when blood pressure is low.
- Treating an asthma attack and missing the other signs.
Related revision
The thinking is the same as in prioritisation questions: treat the threat to life first. Anaphylaxis can also occur with the medicines covered in the medication safety guide, so check allergy status before every drug. Practise with scenario questions in the question bank.
A worked exam scenario
Invented for teaching. A patient starts an antibiotic infusion. Five minutes later she says her throat feels tight, her lips are swelling and she looks pale. Her blood pressure is 82 over 50 and her pulse is 130. What should the nurse do first?
The pattern is airway and circulation problems soon after a likely trigger, which is anaphylaxis. The nurse should stop the infusion, call for help and give intramuscular adrenaline from the protocol or prescription, then lay her flat and give oxygen. Checking the allergy band, repeating observations or giving an antihistamine first all delay the drug that matters. Document the times and the actions afterwards.
Preventing the next reaction
Prevention questions are common. Check the allergy status and the allergy band before every new medicine, a contrast agent or a blood product. Ask about latex, foods and previous reactions, and record what the patient tells you. When a reaction has happened, update the record and tell the patient and the team which trigger is suspected. Teach the patient and family what to avoid and how to use an adrenaline auto-injector if one is prescribed, then check understanding by asking them to show you. Exams reward the answer that closes the loop: record, report, teach.
Frequently asked questions
This article is general educational guidance, not official advice. Exam rules, fees and timelines are set by the Dubai Health Authority and the test provider and can change, so always confirm the latest details on their official channels.
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