The main sign of angioedema is swelling that develops below the skin's surface.

Swollen skin

The swelling is caused by a collection of fluid in the deep layers of the skin.

It most often affects the hands, feet, eyes, lips, or genitals. In severe cases, the inside lining of the throat and bowel can be affected (see below).

The swelling usually appears suddenly, and is more severe than normal hives (nettle rash). It commonly lasts one to three days. There may be a prickling sensation in the affected area before swelling is visible.

The swelling is not itchy and the skin may look a normal colour; however, many people with allergic or idiopathic angioedema also develop urticaria (hives), which is red and itchy.

Other symptoms

As well as visible swellings, angioedema can cause other symptoms, including:

• a hot or painful sensation in the swollen areas
• swelling of the inside of the throat, the windpipe and the tongue, making breathing difficult
• swelling of the conjunctiva (the transparent layer of cells that cover the white part of the eye), which affects vision

People with hereditary angioedema may also experience:

• abdominal (stomach) pain caused by swelling in the stomach and bowel, which can cause nausea, vomiting and diarrhoea
• swelling of the bladder or urethra (the tube that connects the bladder to the genitals), which can cause bladder problems and difficulty passing urine

When to seek medical advice

Contact your GP if you have an episode of angioedema that does not affect your breathing and you have not previously been diagnosed with the condition. You will need to have tests to determine what type of angioedema you have.

When to seek emergency medical advice

Dial 999 to request an ambulance if you suspect that you, or someone you know, is experiencing anaphylaxis (a severe allergic reaction). Tell the operator that you suspect anaphylaxis.

Initial symptoms of anaphylaxis include:

• a feeling of tightness in the chest that leads to breathing problems 
• swelling of the tongue and throat

If you, or the person in your care, has previously been prescribed an adrenaline auto-injector pen, you should use it while waiting for the ambulance to arrive.