Anaphylaxis facts
What is anaphylaxis?
Anaphylaxis refers to a rapidly developing and serious allergic reaction that affects a number of different body systems at one time. Severe anaphylactic reactions can be fatal. Although many patients experience minor allergy symptoms, a small number of people are susceptible to a severe 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 bloodstream. 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.
What is the history of anaphylaxis?
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 reexposure 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.
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 reexposure. 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.
What are common causes of anaphylaxis?
Although anaphylaxis can be due to different causes, there are four major subtypes of anaphylaxis (reactions to food, drugs, latex, and insect stings).
The causes of anaphylaxis are divided into two major groups:
The terms anaphylaxis and anaphylactoid (meaning "like anaphylaxis") are both used to describe this severe allergic reaction. Anaphylaxis is used to describe reactions that are initiated by IgE and anaphylactoid is used in reference to reactions that are not caused by IgE. The effects of the reactions are the same, however, and are generally treated in the same manner. Often, they can not be distinguished initially.
Although it may appear that IgE mediated anaphylaxis occurs upon a first exposure to a food, drug, or insect sting, there must have been a prior, and probably unwitting, sensitization from a previous exposure. One may not remember an uneventful sting or be aware of "hidden" allergens in foods.
What are anaphylaxis symptoms and signs?
Anaphylaxis is a severe reaction that affects multiple areas of the body.
The symptoms of an anaphylactic reaction may occur within seconds of exposure or be delayed 15-30 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
Learn more about: aspirin
These symptoms are often accompanied by
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
Some of the time, the mediators flooding the bloodstream cause a generalized opening of capillaries (tiny blood vessels) which results in
These are the typical features of anaphylactic shock.
What happens after the symptoms begin?
There are three possible outcomes:
Epinephrine, which is also known as "adrenaline," is a drug that acts immediately to cause the blood vessels to contract, thereby preventing fluid leakage. It is one of the medications frequently used to treat anaphylaxis. Epinephrine also helps relax the bronchial tubes, thus relieving breathing difficulty. It also lessens stomach cramps and stops itching and hives. More importantly, epinephrine helps prevent the release of more mediators of the allergic reaction.
In addition to epinephrine, other medications and IV fluids and oxygen will probably be administered once one receives care from a health-care professional. The choice of interventions will depend on the severity of the reaction the patient experiences. Epinephrine given to someone who does not have anaphylaxis can lead to a dangerously fast heartbeat and severe hypertension. It should only be administered by medical personnel familiar with its use and indications or patients who were prescribed an EpiPen by their health-care provider.
Are there any disorders that appear similar to anaphylaxis?
Several disorders may appear similar to anaphylaxis. Fainting (vasovagal reaction) is the reaction that is most likely to be confused with anaphylaxis. The key differences are that in a fainting episode, the affected person has a slow pulse, cool and pale skin, and no hives or difficulty breathing. Other conditions, such as heart attacks, blood clots to the lungs, septic shock, and panic attacks can also be confused with anaphylaxis.
How is anaphylaxis diagnosed?
If someone thinks he or she is having an anaphylactic reaction, the first order of business is to seek emergency care. Once the acute reaction has been treated, one should follow up with a doctor who will probably recommend seeing an allergist. The allergist will assess whether or not the reaction was indeed allergic in nature. Usually, a careful and detailed medical history and selected blood or skin tests can identify the cause. Be prepared to recall any activities that preceded the event, the food and medications ingested, and whether or not one had any contact with rubber products.
Table 1: The Common Causes of AnaphylaxisCauses - IgE MediatedExamplesMedicationsPenicillin, cephalosporin, anesthetics, streptokinase, othersInsect stingsHornet, wasp, yellow jacket, honey bee, fire antFoodsPeanuts, tree nuts, fish, shellfish, eggs, milk, soy, wheatVaccinesAllergy shots, egg and gelatin-based vaccinesHormonesInsulin, possibly progesteroneLatexRubber productsAnimal/human proteinsHorse serum (used in some snake antivenins)Two situations deserve special attention at this point since they are not covered elsewhere but are particularly interesting.
How do we manage anaphylaxis?
The optimal management of anaphylaxis saves lives. An affected or at-risk person must be aware of possible triggers and early warning signs. If someone is prone to these reactions, he or she must be familiar with the use of emergency anaphylaxis treatment kits and always carry them.
If one is aware of what triggers severe reactions and potentially anaphylaxis, a wrist bracelet indicating this can be helpful in case of unresponsiveness. Emergency measures and prevention are central to management. As always, allergic diseases are best treated by avoidance measures, which will be reviewed in detail below.
What are emergency measures used in the treatment of anaphylaxis?
If you suspect that you or someone you are with is having an anaphylactic reaction, the following are important first aid measures. In general, try to perform these in the order that they are presented.
Learn more about: EpiPen
Shots of epinephrine can be given through light clothing such as trousers, skirts, or stockings. Heavy garments may have to be removed prior to injecting. Only inject epinephrine if the patient has a history of anaphylactic reactions or under guidance of a health-care provider.
After 10-15 minutes, if the symptoms are still significant, one can inject another dose of epinephrine if available. Even after the reaction subsides, the individual needs to go to an emergency department immediately. Other treatments may be given, such as oxygen, intravenous fluids, breathing medications, and possibly more epinephrine. Steroids and antihistamines may be given, but these are often not helpful initially and do not take the place of epinephrine. However, they may be more useful in preventing a recurrent delayed reaction.
Do not be surprised if epinephrine makes the individual feel shaky and causes a rapid, pounding pulse. These are normal side effects and are not dangerous except for those with severe heart problems.
What is the history of anaphylaxis?
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 reexposure 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.
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 reexposure. 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.
What are common causes of anaphylaxis?
Although anaphylaxis can be due to different causes, there are four major subtypes of anaphylaxis (reactions to food, drugs, latex, and insect stings).
The causes of anaphylaxis are divided into two major groups:
The terms anaphylaxis and anaphylactoid (meaning "like anaphylaxis") are both used to describe this severe allergic reaction. Anaphylaxis is used to describe reactions that are initiated by IgE and anaphylactoid is used in reference to reactions that are not caused by IgE. The effects of the reactions are the same, however, and are generally treated in the same manner. Often, they can not be distinguished initially.
Although it may appear that IgE mediated anaphylaxis occurs upon a first exposure to a food, drug, or insect sting, there must have been a prior, and probably unwitting, sensitization from a previous exposure. One may not remember an uneventful sting or be aware of "hidden" allergens in foods.
What are anaphylaxis symptoms and signs?
Anaphylaxis is a severe reaction that affects multiple areas of the body.
The symptoms of an anaphylactic reaction may occur within seconds of exposure or be delayed 15-30 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
Learn more about: aspirin
These symptoms are often accompanied by
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
Some of the time, the mediators flooding the bloodstream cause a generalized opening of capillaries (tiny blood vessels) which results in
These are the typical features of anaphylactic shock.
What happens after the symptoms begin?
There are three possible outcomes:
Epinephrine, which is also known as "adrenaline," is a drug that acts immediately to cause the blood vessels to contract, thereby preventing fluid leakage. It is one of the medications frequently used to treat anaphylaxis. Epinephrine also helps relax the bronchial tubes, thus relieving breathing difficulty. It also lessens stomach cramps and stops itching and hives. More importantly, epinephrine helps prevent the release of more mediators of the allergic reaction.
In addition to epinephrine, other medications and IV fluids and oxygen will probably be administered once one receives care from a health-care professional. The choice of interventions will depend on the severity of the reaction the patient experiences. Epinephrine given to someone who does not have anaphylaxis can lead to a dangerously fast heartbeat and severe hypertension. It should only be administered by medical personnel familiar with its use and indications or patients who were prescribed an EpiPen by their health-care provider.
Are there any disorders that appear similar to anaphylaxis?
Several disorders may appear similar to anaphylaxis. Fainting (vasovagal reaction) is the reaction that is most likely to be confused with anaphylaxis. The key differences are that in a fainting episode, the affected person has a slow pulse, cool and pale skin, and no hives or difficulty breathing. Other conditions, such as heart attacks, blood clots to the lungs, septic shock, and panic attacks can also be confused with anaphylaxis.
How is anaphylaxis diagnosed?
If someone thinks he or she is having an anaphylactic reaction, the first order of business is to seek emergency care. Once the acute reaction has been treated, one should follow up with a doctor who will probably recommend seeing an allergist. The allergist will assess whether or not the reaction was indeed allergic in nature. Usually, a careful and detailed medical history and selected blood or skin tests can identify the cause. Be prepared to recall any activities that preceded the event, the food and medications ingested, and whether or not one had any contact with rubber products.
Table 1: The Common Causes of AnaphylaxisCauses - IgE MediatedExamplesMedicationsPenicillin, cephalosporin, anesthetics, streptokinase, othersInsect stingsHornet, wasp, yellow jacket, honey bee, fire antFoodsPeanuts, tree nuts, fish, shellfish, eggs, milk, soy, wheatVaccinesAllergy shots, egg and gelatin-based vaccinesHormonesInsulin, possibly progesteroneLatexRubber productsAnimal/human proteinsHorse serum (used in some snake antivenins)Two situations deserve special attention at this point since they are not covered elsewhere but are particularly interesting.
How do we manage anaphylaxis?
The optimal management of anaphylaxis saves lives. An affected or at-risk person must be aware of possible triggers and early warning signs. If someone is prone to these reactions, he or she must be familiar with the use of emergency anaphylaxis treatment kits and always carry them.
If one is aware of what triggers severe reactions and potentially anaphylaxis, a wrist bracelet indicating this can be helpful in case of unresponsiveness. Emergency measures and prevention are central to management. As always, allergic diseases are best treated by avoidance measures, which will be reviewed in detail below.
What are emergency measures used in the treatment of anaphylaxis?
If you suspect that you or someone you are with is having an anaphylactic reaction, the following are important first aid measures. In general, try to perform these in the order that they are presented.
Learn more about: EpiPen
Shots of epinephrine can be given through light clothing such as trousers, skirts, or stockings. Heavy garments may have to be removed prior to injecting. Only inject epinephrine if the patient has a history of anaphylactic reactions or under guidance of a health-care provider.
After 10-15 minutes, if the symptoms are still significant, one can inject another dose of epinephrine if available. Even after the reaction subsides, the individual needs to go to an emergency department immediately. Other treatments may be given, such as oxygen, intravenous fluids, breathing medications, and possibly more epinephrine. Steroids and antihistamines may be given, but these are often not helpful initially and do not take the place of epinephrine. However, they may be more useful in preventing a recurrent delayed reaction.
Do not be surprised if epinephrine makes the individual feel shaky and causes a rapid, pounding pulse. These are normal side effects and are not dangerous except for those with severe heart problems.
Source: http://www.rxlist.com
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 reexposure. 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.
Source: http://www.rxlist.com
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