Cardiovascular symptoms of anaphylaxis

These are emergency signs. Give adrenaline with an auto-injector as directed, contact local emergency services immediately, and keep the person in a safe position while help is coming.

During anaphylaxis, blood vessels can widen and fluid can move out of the circulation. Blood pressure may fall, leaving the brain and other organs with inadequate blood flow. The person may look pale or feel clammy, weak, light-headed, or unable to remain upright.

A rapid heartbeat can accompany the reaction, but pulse changes alone do not establish the diagnosis. Circulatory symptoms may occur alongside throat swelling, wheezing, vomiting, abdominal pain, or skin changes; a rash is not required for a severe reaction.

Use the adrenaline auto-injector in the outer thigh as soon as anaphylaxis is suspected. Note the time it was given, call emergency services, and use another device if symptoms persist and the person's action plan or emergency dispatcher instructs you to do so.

Lay the person flat and raise their legs when possible. Avoid sitting or standing them suddenly, because this can further reduce blood flow. If they are pregnant, position them on their left side. If unconscious but breathing, use the recovery position; start cardiopulmonary resuscitation if normal breathing stops.

Sudden faintness, collapse, confusion, marked weakness, loss of consciousness, or pale and clammy skin after possible allergen exposure requires an emergency response. The same applies when circulation symptoms accompany breathing difficulty or swelling of the tongue or throat.

Improvement after adrenaline does not remove the need for assessment. Symptoms can return, and clinicians may need to monitor breathing and circulation before discharge.

Discuss how to distinguish your early reaction signs from ordinary light-headedness, which medicines or health conditions may affect emergency management, where to carry auto-injectors, and how family members should position you after a collapse. Ask for hands-on device training and an updated written action plan.