What should you know about anaphylaxis vital signs?

During anaphylaxis, widened blood vessels and fluid movement out of the circulation can lower blood pressure. The heart may beat faster to compensate, while a weak pulse, pale or clammy skin, dizziness, confusion or fainting can signal reduced circulation. Airway narrowing can increase the breathing rate, cause wheezing or lower an oxygen reading.

A single normal measurement can be misleading early in a reaction. Diagnosis and treatment depend on the overall pattern after a likely trigger, including skin or mouth changes, breathing difficulty, repeated vomiting, severe abdominal symptoms, and signs of poor circulation.

Use the person’s prescribed adrenaline auto-injector immediately when anaphylaxis is suspected, following its instructions, and call emergency services. Do not delay adrenaline to find a blood-pressure monitor, pulse oximeter or thermometer. If symptoms continue and the person’s action plan directs another dose, use the next available auto-injector as instructed.

Keep the person lying flat with legs raised if tolerated. If breathing is difficult, they may need to sit with legs extended; if unconscious but breathing, place them on their side. Avoid having them stand or walk. Stay with them, note the likely trigger and treatment time, and give the used device to the emergency team.

Anaphylaxis is an emergency. Seek immediate help for trouble breathing, throat tightness, a hoarse voice, blue or grey colour, collapse, marked drowsiness, confusion, or a weak pulse after a possible allergen exposure. Also act urgently when symptoms affect more than one body system, such as hives together with vomiting or wheezing. Symptoms can return after seeming to settle, so medical observation is needed after adrenaline is used.

After recovery, ask which symptoms should trigger adrenaline, how to check and store your auto-injector, whether you need more than one device, and which suspected allergens merit assessment. Request a written action plan and make sure family, school or workplace contacts know where the medicine is kept and how to use it.