Medicines for Anaphylaxis

What it is

Anaphylaxis is a severe, potentially life-threatening allergic reaction that develops rapidly, usually within minutes of exposure to a trigger. It is a medical emergency that needs immediate treatment. Common triggers include certain foods (such as nuts, shellfish, milk, or eggs), insect stings (such as wasp or bee stings), some medicines, and, less commonly, other substances. In anaphylaxis, the immune system overreacts and releases chemicals that cause widespread effects in the body. The signs come on quickly and can include: difficulty breathing (wheezing, a persistent cough, or noisy breathing), a tight throat or difficulty swallowing, swelling of the tongue, throat, lips, or face, a widespread itchy rash or hives, feeling lightheaded, faint, or dizzy, a fast heartbeat, tummy pain, feeling or being sick, a sense of impending doom, and, in severe cases, collapse and loss of consciousness. The most dangerous features are difficulty breathing and a drop in blood pressure (which can cause fainting or collapse). Anaphylaxis requires immediate action: adrenaline (given as an injection, often via an adrenaline auto-injector such as an EpiPen) is the essential first treatment, and emergency services should be called straight away. People known to be at risk of anaphylaxis are usually prescribed adrenaline auto-injectors to carry, and taught how and when to use them, alongside a plan to avoid their triggers. Because anaphylaxis is rapid and life-threatening, recognising the signs, using adrenaline without delay, and calling for emergency help are the key, potentially life-saving actions.

How it is treated

Anaphylaxis is a medical emergency, and the priority is immediate treatment: recognising the reaction, giving adrenaline straight away, and calling emergency services. If anaphylaxis is suspected, the essential steps are to: use an adrenaline auto-injector (such as an EpiPen) immediately if one is available, injecting into the outer thigh as trained; call emergency services (999) straight away, saying it is anaphylaxis; help the person into a position that helps (usually lying down with legs raised if they feel faint, or sitting up if breathing is difficult, and on their side if unconscious but breathing); and give a second adrenaline dose after 5 minutes if there is no improvement and another auto-injector is available. Even if adrenaline is given and the person improves, they still need emergency medical assessment, because the reaction can return. In hospital, further treatment and monitoring are provided. After an episode, it is important to identify and avoid the trigger where possible, to be referred to a specialist (allergy service) for assessment and an emergency plan, and — for those at risk — to be prescribed adrenaline auto-injectors and taught how and when to use them (and for those around them, such as family or school, to be trained too). Carrying adrenaline auto-injectors at all times (usually two), knowing how to use them, avoiding known triggers, and having an emergency action plan are central to managing the risk. The key, potentially life-saving messages are: recognise anaphylaxis (rapid onset, breathing difficulty, swelling, faintness after a trigger), give adrenaline without delay, and call emergency services — do not wait to see if it settles. The reassuring point is that, with prompt adrenaline and emergency care, and with good avoidance and preparedness, anaphylaxis can be treated and managed.