A severe, potentially fatal allergic reaction to certain substances
Anaphylaxis, also known as anaphylactic shock, is a rare and severe type of allergic reaction that occurs in people who have developed an extreme sensitivity to a specific substance (allergen). The reaction occurs throughout the body, causing a sudden drop in blood pressure and narrowing of the airways, and it can be fatal unless immediate treatment is available. Ana-phylaxis is often triggered by insect stings or by certain drugs such as the antibiotic penicillin (see Drug allergy). Foods such as nuts or strawberries may also trigger this serious form of allergic reaction (see Food allergy).
If you have an extreme sensitivity to a substance, you may experience some or all of the following symptoms as soon as you are exposed to it:
Sudden feeling of extreme anxiety.
Swollen face, lips, and tongue.
Wheezing and difficulty breathing.
In some cases, an itchy, red rash (see Urticaria) and flushing of the skin.
Light-headedness or, in some cases, loss of consciousness.
If either you or anyone you are with develops these symptoms, you should call an ambulance immediately.
You should avoid any substance to which you are sensitive, especially if you have had a previous anaphylactic reaction. You may be given epinephrine to self-inject (see Emergency aid for anaphylaxis). You will also be advised to carry an emergency card or bracelet to alert others to your allergy.
From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.