Anaphylaxis

        Anaphylaxis refers to a rapidly developing and serious allergic reaction that affects a number of different areas of the body at one time. Severe anaphylactic reactions can be fatal. Most people experience allergy symptoms only as a minor annoyance. However, a small number of people are susceptible to a reaction that can lead to shock or even death.
Anaphylaxis is often triggered by substances that are injected or ingested and thereby gain access into the blood stream. An explosive reaction involving the skin, lungs, nose, throat, and gastrointestinal tract can then result. Although severe cases of anaphylaxis can occur within seconds or minutes of exposure and be fatal if untreated, many reactions are milder and can be ended with prompt medical therapy.
 Anaphylaxis mean
To fully understand this term, we need to go back almost 100 years. The story begins on a cruise aboard Prince Albert I of Monaco's yacht. The Prince had invited two Parisian scientists to perform studies on the toxin produced by the tentacles of a local jellyfish, the Portuguese Man of War. Charles Richet and Paul Portier were able to isolate the toxin and tried to vaccinate dogs in the hope of obtaining protection, or "prophylaxis," against the toxin. They were horrified to find that subsequent very small doses of the toxin unexpectedly resulted in a new dramatic illness that involved the rapid onset of breathing difficulty and resulted in death within 30 minutes. Richet and Portier termed this "anaphylaxis" or "against protection." They rightly concluded that the immune system first becomes sensitized to the allergen over several weeks and upon re-exposure to the same allergen may result in a severe reaction. An allergen is a substance that is foreign to the body and can cause an allergic reaction in certain people.
Allergy Facts
• The first documented case of presumed anaphylaxis occurred in 2641 B.C. when Menes, an Egyptian pharaoh, died mysteriously following a wasp or hornet sting. Later, in Babylonian times, there are two distinct references to deaths due to wasp stings.
• Charles Richet was awarded the Nobel Prize in 1913 for his work on anaphylaxis.
Richet went on to suggest that the allergen must result in the production of a substance, which then sensitized the dogs to react in such a way upon re-exposure. This substance turned out to be IgE.
In the first part of the 20th century, anaphylactic reactions were most commonly caused by tetanus diphtheria vaccinations made from horse serum. Today, human serum is used for tetanus prevention, and the most common causes of anaphylaxis are now penicillin and other antibiotics, insect stings, and certain foods.
 Symptoms
The symptoms of an anaphylactic reaction may occur within seconds of exposure, or be delayed 15 to 30 minutes, or even an hour or more after exposure (typical of reactions to aspirin and similar drugs). Early symptoms are often related to the skin and include:
• Flushing (warmth and redness of the skin),
• itching (often in the groin or armpits), and
• hives.
These symptoms are often accompanied by:
• a feeling of "impending doom,"
• anxiety, and
• sometimes a rapid, irregular pulse.
Frequently following the above symptoms, throat and tongue swelling results in hoarseness, difficulty swallowing, and difficulty breathing.
Symptoms of rhinitis (hay fever) or asthma may occur causing:
• a runny nose,
• sneezing, and wheezing, which may worsen the breathing difficulty,
• vomiting, diarrhea, and stomach cramps may develop.
About 25% of the time, the mediators flooding the blood stream cause a generalized opening of capillaries (tiny blood vessels) which results in a drop in blood pressure, lightheadedness, or even loss of consciousness. These are the typical features of anaphylactic shock.
Can anaphylaxis be prevented?
Preventing anaphylaxis is the ideal form of treatment. However, that may not always be easy since insect stings are frequently unanticipated and allergic foods are often hidden in a variety of different preparations. A consultation with an allergist is vital in helping you identify the trigger(s) and providing you with information and instruction on how to best avoid them. You will learn how to use emergency kits and how to become prepared for any reaction in the future.
These are three situations in which preventive treatment might be offered by the allergist.
1. Allergy shots may be suggested to some people with wasp, yellow jacket, hornet, honey bee, or fire ant reactions. This form of treatment gives 98% protection against the first four insect reactions, though somewhat less protection against fire ant reactions.
2. Pre-medication is most helpful in preventing anaphylaxis from x-ray dyes. Alternative dyes that are less likely to cause reactions may be available.
3. Desensitization to problematic medications is often effective. This process is accomplished by gradually increasing the amount of the medication given under controlled conditions. Sensitivities to penicillin, sulfa drugs, and insulin have been successfully treated in this way.
Anyone known to be at risk for anaphylaxis should wear a Medic-Alert bracelet that clearly states the allergic trigger, the risk of anaphylaxis, and the availability of an epinephrine kit.