What is anaphylaxis?
This is the most severe form of an allergic reaction and can lead to death. Anaphylaxis or anaphylactic shock involves the entire body. A number of allergens and a number of circumstances can cause it. The reaction occurs when specific cells in the body, mast cells or basophils, release mediators or chemicals that have an effect on the body.
When the reactions are triggered by an allergen the process is called anaphylaxis. Sometimes the reactions are triggered by other mechanisms and are called anaphylactoid reactions. The symptoms are the same and in the majority of instances, the treatment is the same. The two processes do differ in the mechanism of how they cause the reaction and they differ in how they can be diagnosed. With anaphylactic reactions, the culprit is due to an antibody, IgE that is made by the patient.
These are substances that cause the patient to make a specific allergic response or IgE antibody to the substance. Skin testing can discover substances that cause the patient to make such an antibody. There are situations where the reaction occurs by a different mechanism. The substance causes the reaction and does not involve IgE. In these situations, skin testing will not help.
Common examples of the two types of reactions include:
Due to IgE
- Stinging Insects
- Medications-especially antibiotics allergy-anaphylaxis.jsp
- Injections- vaccines, allergy shots
Non-IgE mediated reactions
- Infusion of human blood products
- Nonsteroidal anti-inflammatory agents (NSAIDS)
- Direct releasers- contrast media, chemotherapeutic agents
- Idiopathic- where no cause is found
What happens with anaphylaxis:
The reaction can involve a number of body systems. Usually there will be a skin reaction (hives, swelling) and a second organ system- the gastrointestinal tract, the cardiovascular system, or the airway.
Features of anaphylaxis are:
- Skin - flushing, hives, swelling, itchy skin
- Cardiovascular - rapid heart rate, low blood pressure, shock, arrhythmias, loss of consciousness
- Gastrointestinal - distension, vomiting, diarrhea, nausea, pain, cramps
- Respiratory - swelling of the airway, wheezing, asphyxiation
- Other symptoms - sweaty, sense of impending doom, metallic taste
Facts on Anaphylaxis:
The time of onset can be within seconds and can take a number of hours to evolve. The more serious reactions tend to occur early. The reactions may come in two phases, an early phase and one that may be delayed for 6-10 hours. When the reaction occurs more than three hours after the exposure, there is a tendency for it to be less severe. Over 70% of patients who have anaphylaxis will have respiratory systems and over 80% will have hives or swelling of the deep tissue of the skin, lips, or tongue.
The occurrence of anaphylaxis with exercise has been described. Those who have this syndrome experience generalized itchiness of the skin with or without hives, low blood pressure, and difficulty breathing. The ingestion of a food such as celery, wheat, or shellfish within a few hours prior to exercise may be contributory to the problem.
This is a medical emergency! Epinephrine or adrenaline is to be given immediately. An antihistamine should also be given. These reactions need to be treated as soon as possible and the patient should be taken to the nearest emergency facility. The sooner the reaction is treated, the less severe it will be. Be sure to remove any possible offending agent that may be causing the reaction to progress.
The best treatment is avoidance. An evaluation will help identify the agent and lead to information on how to avoid it. A specialist should be involved. You should know how to administer the epinephrine to yourself if you are the patient or how to use it on your child. A medical alert bracelet should be worn.
A rule for the food allergic patient it that if you don't know what is in the product, do not eat it. Most of those who have died from food reaction were aware of their sensitivity and became careless.