Hereditary angioedema

Hereditary angioedema (HAE) is a rare inherited condition causing recurrent, unpredictable episodes of severe swelling, most often affecting the skin, abdomen, or airway, due to a deficiency or malfunction of a protein called C1-inhibitor. Living with HAE often means carrying emergency medication at all times and having a clear plan for managing attacks wherever they occur. With appropriate modern treatment, most people are able to manage the condition well and lead full lives.

Attacks can be triggered by physical trauma, dental procedures, infections, stress, or certain medications such as ACE inhibitors or oestrogen-containing contraceptives, though many occur without any identifiable trigger. This unpredictability is one of the more challenging aspects of living with the condition. Having on-demand treatment readily accessible at all times helps manage this unpredictability.

Attacks typically involve swelling of the skin, severe abdominal pain from gut-wall swelling, or, most seriously, swelling of the throat or tongue affecting breathing. Symptoms usually build up gradually over hours rather than appearing instantly, which can give some warning time to start treatment. Unlike allergic reactions, HAE swelling is not usually accompanied by hives or itching.

While airway attacks are potentially life-threatening and need emergency treatment, with a proper management plan, most people with HAE are able to live full, active lives between and around attacks. Having a personalised action plan, appropriate on-demand medication always accessible, and, where appropriate, preventive treatment significantly reduces both the frequency and the risk associated with attacks. Regular specialist follow-up helps ensure your management plan continues to fit your needs over time.

On-demand treatments, used to stop an attack once it starts, include C1-inhibitor concentrate and icatibant, given by injection as early as possible in an attack. For people with frequent or severe attacks, regular preventive medication can significantly reduce how often attacks occur. Your specialist immunology or allergy team will work with you to find the right combination of on-demand and, if needed, preventive treatment for your specific attack pattern.

HAE can be affected by hormonal changes, and pregnancy, in particular, can sometimes change attack frequency, either increasing or decreasing it, which needs specific specialist planning. Similarly, planned surgery or dental work usually requires specific preventive treatment beforehand to reduce the risk of triggering an attack. Discussing any major life event or planned procedure with your HAE specialist team well in advance allows appropriate precautions to be put in place.

This distinction is one of the most important things for anyone with HAE, their family, and any healthcare providers to understand: standard allergy treatments like antihistamines, adrenaline, and steroids do not work for HAE attacks, since the underlying mechanism is completely different from an allergic reaction. Using the wrong treatment, or waiting to see if allergy treatment works, can waste crucial time during a dangerous airway attack. This is why carrying clear medical information about your HAE diagnosis and specific treatment needs is so important.

Use your prescribed on-demand treatment as soon as an attack starts, following your personal action plan, and seek emergency care immediately for any swelling affecting the throat, tongue, or causing breathing difficulty, even after using treatment. Regular follow-up with your specialist immunology or allergy team, typically arranged as part of standard ongoing care, helps ensure your management plan remains appropriate over time. Do not hesitate to contact your specialist team between scheduled appointments if your attack pattern changes or you have any concerns.