ANAPHYLAXIS

Anaphylaxis is a potentially life-threatening allergic reaction. The two most common causes of fatal anaphylaxis are allergies to penicillin or allergies to bee stings. Other causes include aspirin, antiinflammatory <Au: change–delete of hyphen-- OK?> agents, and other antibiotics, including the classes of cephalosporins and sulfur products. Peanuts and nuts used in many Chinese foods <AU: is it the peanuts and nuts used in the Chinese food? Or just the peanuts and nuts themselves? Or should it be the additive monosodium glutamate (named below), which is used in Chinese food?> can trigger this reaction. Eggs, milk, shellfish, and the additive called monosodium glutamate (MSG) are other potential causes. Contrast material used for certain radiographs (x-rays) (e.g., intravenous pyelogram [IVP], computed tomography [CT], or magnetic resonance imaging [MRI]) can also lead to anaphylaxis in some people.

Each year in the United States 20,000 to 50,000 people develop anaphylaxis. The reaction is not contagious, meaning it cannot be transmitted from one person to another. Anaphylaxis is curable, but it must be treated immediately. Time is of the essence, since the reaction can begin within seconds after the exposure to the allergen (the substance causing the allergic reaction).

Anaphylaxis is detected by the history of exposure to an allergen, such as a bee sting, and the clinical presentation. Typical symptoms begin within seconds to minutes (but may be delayed up to 1 hour after exposure) and result in shortness of breath, wheezing, swelling of the eyes, face, tongue, and neck along with a sensation of throat tightening. This can lead to hoarseness and severe breathing problems. Skin flushing, hives, itching, and redness also occur with chills and sweating. The reaction can be catastrophic, leading to death from respiratory arrest or from cardiac shock.

The diagnosis of anaphylaxis is usually obvious with the above-mentioned symptoms and the known exposure or known past history of anaphylaxis. Treatment must be immediate. It is important to get to the nearest emergency room for treatment. Treatment consists of an injection of epinephrine. This dose may need to be repeated, depending on symptoms. If there is severe respiratory distress, a breathing machine (mechanical ventilator) may need to be used. Antihistamines are also used to combat the allergic reaction. Diphenhydramine 25 to 50 mg either intravenous or intramuscular is commonly recommended in addition to respiratory treatments using albuterol inhaled nebulizers.

In severe cases, large quantities of intravenous fluid are needed to sustain blood pressure along with continuous infusion of either epinephrine, norepinephrine, or dopamine.

If the reaction is easily reversed and no hospitalization is required, antihistamines may be prescribed to be taken over the next few days along with corticosteroids (prednisone). These drugs help to prevent recurrence of symptoms.

Finally, once the diagnosis and treatment is established, prevention is the best form of treatment. It is advisable to carry a self-administered epinephrine kit (Epi-pen or Ana-Kit). This is especially indicated for the individual who develops immediate anaphylaxis, with no time to get to the emergency room. The individual can self-inject the epinephrine into the thigh on route to the emergency room.

• Understand that anaphylaxis can occur within seconds after exposure to the allergen. If you already know you have had an anaphylactic reaction to bee stings or to certain antibiotics or food products and you have been exposed to the allergen, immediately go to the nearest emergency room.
• Carry and use the prefilled epinephrine kit if you have been exposed to the allergen. The syringe and needle are already in place and should be placed at a right angle over the outside front part of the upper thigh. Press hard into the thigh until the injection goes in and leave it there for a few seconds. In more acute situations this can be done through clothing, otherwise applying the injection over the skin is the better way. The injector is then removed as you are on your way to the emergency room.
• Remember that restaurants don't know that you have allergies to certain foods. It is important that you review what is on the menu and what is added to the meal or what the meal is cooked with. A common situation occurs with Chinese foods adding nuts to their dishes. Some people may not know this and expose themselves to the allergen. <Au: is it the nuts or the monosodium glutamate (MSG), which is often added to Chinese food without notation on the menu?>

• Don't take risk. If you know you are allergic to yellow jackets or hornets, don't go in areas where you see the insects.
• Don't forget to wear a Medic Alert ID describing substances that have caused anaphylaxis.
• Don't forget to mention to any new physician you visit that you have allergies to certain products, especially if they involve contrast material used for certain radiographs (x-rays). This helps the physician avoid the mistake of ordering a test placing you at risk for the anaphylaxis.

• If you have had an anaphylactic reaction and have been treated. Your doctor can refer you to an allergist to discuss an option called desensitization.
• If you have any of the above-mentioned symptoms.

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