Angioedema: Symptoms, Causes and Treatment

Angioedema is sudden swelling in deeper tissues, often affecting the lips, face, tongue, hands, feet or genitals. It develops when fluid escapes from small blood vessels into surrounding tissue. Some episodes occur with raised, itchy hives, while others happen without a visible rash. Swelling inside the tongue or throat can obstruct breathing and needs emergency care.

Angioedema commonly presents with facial swelling, swollen lips or broader skin swelling. The affected area may feel tight, warm, tender or mildly painful. Itching and hives point more toward a histamine-related episode, whereas non-itchy swelling without hives can follow a different pathway. Abdominal involvement may cause cramping, nausea or vomiting.

Call emergency services immediately for trouble breathing, noisy breathing, throat tightness, a hoarse or changed voice, difficulty swallowing, faintness, or rapidly increasing tongue or mouth swelling. Do not wait for a rash to appear.

Histamine-related angioedema may follow an allergic reaction to a food, medicine, insect sting or another exposure, and it may accompany hives. Some episodes have no identifiable trigger. A separate, bradykinin-related form can be linked to certain blood-pressure medicines or inherited changes affecting proteins that control swelling. These pathways matter because they do not respond to the same medicines.

Swelling can appear over minutes or build more gradually, depending on its cause. A local episode may settle, spread to nearby tissue or recur after seeming to improve. Mouth, tongue and throat symptoms can progress unpredictably, so emergency warning signs take priority over watching the swelling at home. Recurrent attacks may follow similar triggers but can differ in location and severity.

Risk can be higher in people with previous angioedema or allergic reactions, exposure to a known trigger, use of medicines associated with swelling, or relatives with recurrent unexplained attacks. Autoimmune or blood disorders can be relevant in some acquired cases. A past mild episode does not predict that every future episode will stay mild.

A clinician examines the location and extent of swelling and first checks the airway, breathing and circulation. The history covers timing, hives or itching, foods, stings, recent illnesses, every medicine and supplement, previous episodes, abdominal symptoms and family history. Photographs taken during an episode can help if swelling has resolved before the appointment.

Blood tests are not needed for every isolated episode. With recurrent swelling without hives, a clinician may request tests of the complement system and proteins involved in hereditary angioedema, then interpret them alongside the clinical pattern. Allergy assessment may be useful when a specific immediate trigger is suspected.

Treatment starts with airway safety and depends on the mechanism. A suspected severe allergic reaction requires immediate emergency treatment; people prescribed an adrenaline auto-injector should follow their emergency plan and still call emergency services. Antihistamines can help histamine-related swelling and hives. A clinician may use an oral corticosteroid in selected inflammatory or allergic episodes, but this is not suitable for every cause.

Bradykinin-related angioedema needs a different approach. Clinicians may stop or replace a suspected medicine and use a targeted treatment for hereditary or acquired forms. Do not stop a prescribed medicine without urgent medical advice unless your emergency care team directs you to do so.

Keep a record of when swelling starts, where it occurs, accompanying hives or abdominal symptoms, foods, medicines, illness and other possible triggers. Carry prescribed rescue medicine and written instructions in an accessible place. Tell close contacts how to recognise airway symptoms and where emergency medicine is kept. Medical identification can be helpful for a diagnosed hereditary form or a serious medicine reaction.

The most serious complication is upper-airway obstruction from tongue or throat swelling. Severe allergic reactions can also affect breathing and circulation. Bowel-wall swelling can lead to marked pain, vomiting and dehydration. Repeated unpredictable attacks may disrupt sleep, work, travel and eating, which is why a clear diagnosis and personalised action plan are valuable.

Avoid a confirmed trigger and make sure medicine reactions are clearly recorded in your health information. Review suspected prescription triggers with the prescriber so an appropriate alternative can be chosen. For recurrent or hereditary angioedema, a specialist may recommend preventive medicine, a plan for procedures or dental work, and treatment to keep available for an attack.

An allergy and immunology specialist can investigate suspected allergic, recurrent or hereditary angioedema. A dermatologist may assess swelling that occurs with hives or other skin findings. Bring your medicine list, photographs, episode diary, family history and any emergency treatment records. Emergency symptoms should go directly to emergency care rather than waiting for a clinic appointment.