Anaphylaxis is an severe, whole-body allergic reaction. After an initial exposure to a substance like bee sting toxin, the person's immune system becomes sensitized to that allergen. On a subsequent exposure, an allergic reaction occurs. This reaction is sudden, severe, and involves the whole body. Anaphylaxis occurs when a person is exposed to a trigger substance, called an allergen, to which they have already become sensitized.
Minute amounts of allergens may cause a life-threatening anaphylactic reaction. Anaphylaxis may occur after ingestion, inhalation (though this is rare), skin contact or injection of an allergen. The most severe type of anaphylaxis—anaphylactic shock—will usually lead to death in minutes if left untreated.
Although anaphylaxis is the most dangerous type of allergic reaction, it's also the least common. Fortunately, you can be prepared to respond quickly and effectively to an allergy emergency by knowing the signs and symptoms of a severe allergic reaction and by carrying emergency medication with you.
It's also important to do everything you can to prevent exposure to life-threatening allergens.The symptoms, treatment, and risk of death are identical, but "true" anaphylaxis is always caused directly by degranulation of mast cells or basophils that is mediated by immunoglobulin E (IgE), and pseudo-anaphylaxis occurs due to all other causes.
The government ordered stronger label warnings for an injected asthma medication because of reports some patients taking the drug, marketed as Xolair, had suffered a delayed and potentially life-threatening reaction known as anaphylaxis.
XOLAIR is a different type of medication, the first to treat the attacks and symptoms of allergic asthma by blocking immunoglobulin E (IgE), an underlying cause of allergic asthma.
IgE is a substance that naturally occurs in your body in small amounts. When a person who has allergic asthma is exposed to an allergen, his or her body produces too much IgE. When these IgE antibodies combine with allergens, chemicals called mediators are released. In turn, the release of mediators causes the swelling and inflammation of the airways-the symptoms of allergic asthma.
A patient experiencing anaphylaxis might have trouble breathing, feel tight in the chest, have swelling in the mouth and throat, suffer dizziness or feel faint, or have itching and hives.
The risk of anaphylaxis was known when Xolair, also called omalizumab, was approved as an asthma treatment in 2003. But the Food and Drug Administration ordered the drug manufacturer, Genentech, Inc., to strengthen the label warnings because of reports of patients having a delayed reaction of anaphylaxis or reacting to a subsequent dose even when they had no problems after a first dose.
The new warning says:
• Doctors should observe patients for at least two hours after the drug is injected and be ready to manage a potentially life-threatening reaction.
• Anaphylaxis can occur even if a patient did not react to a previous Xolair injection.
• Anaphylaxis can occur up to 24 hours after the injection is given.
• Patients using Xolair should be prepared for to treat themselves for anaphylaxis in emergency situations.
Anaphylaxis is a life-threatening medical emergency because of rapid constriction of the airway, often within minutes of onset, which can lead to respiratory failure and respiratory arrest. Brain and organ damage rapidly occurs if the patient cannot breathe. Due to the severe nature of the emergency, patients experiencing or about to experience anaphylaxis require the help of advanced medical personnel.
First aid measures for anaphylaxis include rescue breathing (part of CPR). Rescue breathing may be hindered by the constricted airways, but if the victim stops breathing on his or her own, it is the only way to get oxygen to them until professional help is available.
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