Angioedema

Angioedema is rapid swelling in the deep layers of the skin and the mucous membranes: fluid leaves the vessels and collects in the surrounding tissue. It looks like a lopsided bulge of a lip, an eyelid, a hand or the tongue. Most episodes settle within a couple of days and are not dangerous, but this kind of swelling has two features worth reading about: it can close off breathing, and it comes in two quite different forms that are treated in different ways.

What the swelling looks like

The swelling builds over anything from minutes to hours and takes in a whole area rather than appearing as a patch. The skin over it is a normal colour or slightly pink. What itches is usually not the swelling itself: alongside it there may be an itchy weal rash, urticaria. Sometimes a feeling of tightness or tingling comes first, before the swelling is visible.

Its favourite places:

• lips, eyelids, cheeks and ears, so that a face changes beyond recognition within an hour;
• the tongue, the soft palate and the voice box, which is the dangerous version;
• hands and feet, when rings and shoes stop going on;
• the external genitals;
• the wall of the bowel, where nothing shows on the outside while inside there is severe cramping pain, vomiting and diarrhoea.

The bowel version is deceptive: people are taken in with a suspected surgical abdomen and are sometimes operated on unnecessarily. If such attacks of pain keep coming back and coincide with swelling of the face or hands, say so to the doctor plainly.

Two mechanisms, and why that is the main point

Behind swellings that look identical lie two different processes, and which one it is decides the whole treatment.

Histamine-driven. This is allergy and the reactions related to it. The swelling develops within minutes, almost always comes with urticaria and itching, and lasts a few hours or up to a day. Antihistamines and steroids help, and adrenaline when life is at risk.

Bradykinin-driven. Neither allergy nor histamine takes part here, so there is no itching and no urticaria. The swelling grows more slowly, over hours, and lasts two to four days. This group covers hereditary angioedema, swelling caused by certain blood pressure medicines, and acquired forms. The crucial point: antihistamines, steroids and adrenaline have almost no effect on this kind of swelling. In an emergency they are given anyway, because the commoner allergic version is treated first, but a lack of response is itself a clue. There are medicines that act on the bradykinin pathway specifically, and someone with an established diagnosis usually carries them.

Hence a practical conclusion: swelling without itching and without a rash, which keeps returning and responds poorly to the usual measures, is a reason to look for the second mechanism rather than to increase the antihistamine dose.

Where it comes from

• Allergy. Nuts, fish and shellfish, egg, milk; wasp and bee stings; medicines, most often antibiotics; latex. The swelling appears soon after the contact.
• Blood pressure medicines from the ACE inhibitor group. A cause that is missed again and again. Swelling of the lips and tongue can happen for the first time after months or even years of taking them uneventfully, so hardly anyone thinks of blaming the tablet. The drug is stopped for good and the doctor chooses a replacement.
• Painkillers. Aspirin and other anti-inflammatory drugs sometimes cause swelling without any true allergy.
• Hereditary angioedema. A rare condition in which a regulatory protein in the blood is missing or works badly. It passes to a child with a one in two chance and usually starts in childhood or adolescence. Attacks are triggered by injury, dental treatment, surgery and stress, and in women by contraceptives containing oestrogen.
• The acquired form. It resembles the hereditary one but begins in adult life and is sometimes linked to diseases of the blood and lymphatic system or to autoimmune disease.
• No cause found. That is where the search ends for a sizeable share of people.

When to call an ambulance

Swelling of the airway moves fast and leaves no time for weighing things up. Call the emergency services if any one of these appears:

• the tongue, lips or throat swell and the voice turns hoarse or muffled;
• breathing is hard, noisy or wheezy, or there is a feeling of choking;
• swallowing is difficult, or there is a lump or tightness in the throat;
• skin, lips or tongue turn grey, blue or very pale, which on dark skin shows up better on the palms and soles;
• sudden weakness, dizziness, confusion or loss of consciousness;
• a child has gone floppy, is not reacting as usual and cannot hold their head up.

Swelling together with urticaria, a drop in blood pressure or vomiting after food, a sting or a medicine is anaphylaxis. An adrenaline auto-injector, if there is one, goes into the outer thigh straight away without waiting for things to get worse, and the ambulance is still called: the reaction can return several hours later. Sitting or lying with the legs raised is better than standing. With hereditary angioedema people go to hospital even when their own medicine has already been given.

How it is worked out and treated

In an acute episode the airway comes first: in hospital the throat is examined, breathing is secured if necessary and the person is watched for several hours. Then comes the search for the cause, and here an accurate account helps.

The doctor wants to know how long the swelling took to build and how long it lasted, whether there was itching and a rash, what happened in the previous day (food, a sting, a new medicine, an injury, a trip to the dentist), whether relatives have had similar episodes, and which blood pressure tablets you take. Those answers usually show where to look.

As for tests, where a bradykinin origin is suspected the complement proteins are checked, including the C4 fraction and the level and activity of the regulatory protein; where allergy is suspected, specific antibodies and skin tests, and sometimes the enzyme tryptase in the first hours after a severe reaction.

Treatment depends on what is found. For allergic swelling: removing the cause, antihistamines and, in severe reactions, a short course of steroids; for anaphylaxis, adrenaline. For swelling caused by ACE inhibitors: stopping the drug and changing the blood pressure regimen. For the hereditary form there are medicines that block the bradykinin pathway directly or replace the missing protein, and where attacks are frequent, continuous preventive treatment is added.

Living with repeated swellings

• Keep a short diary: the date, what swelled, how long it lasted and what happened the day before. Two lines per episode are enough to reveal a pattern six months on.
• Carry what has been prescribed, the adrenaline auto-injector or the medicine for an attack, and keep an eye on the expiry date.
• Get a bracelet or a card with the diagnosis: during a severe episode you are unlikely to be able to explain it yourself.
• Warn the dentist and the surgeon in advance: cover with medication may be needed before a procedure.
• Write down the name of the medicine that caused the swelling and mention it every time something new is prescribed.
• With the hereditary form, discuss contraception and the testing of relatives with your doctor.

Online consultation

An online appointment fits between attacks, not at the moment the throat is swelling. In it the doctor will go through the history of your episodes, help separate an allergic origin from a bradykinin one, look over your medicine list for the drugs that cause swelling in their own right, explain which tests are worth doing and point you towards an allergist or an immunologist as the next step. They will also help put together a clear plan for the next attack. Acute swelling with difficulty breathing cannot be treated remotely: that needs an ambulance.

This material is for information only and does not replace medical advice.