What causes a food allergy?
A food allergy is an immune system response to a food that has been ingested and that the body mistakenly believes is harmful. Initial exposure must occur before an allergic reaction can take place. Upon first exposure, the immune system creates a type of protein called an antibody that circulates through the blood, working against a specific food. When that food is eaten again, the immune system releases massive amounts of chemicals, including histamine, to protect the body. These chemicals trigger a cascade of allergic symptoms that can affect the respiratory system, the gastrointestinal tract, the skin, and/or the cardiovascular system.
What are the most common symptoms of an allergic reaction to food?
- Mouth: swelling of the lips
- Digestive tract: stomach cramps, vomiting, diarrhea
- Skin: hives, rashes or eczema
- Airways: wheezing or breathing problems
How can I avoid food allergies?
People with allergies must avoid foods that trigger symptoms. For people with true food allergies, the simple pleasure of eating can turn into an uncomfortable, and sometimes even dangerous, situation. For some, food allergies cause only hives or an upset stomach; for others, one bite of the wrong food can lead to serious illness or even death.
Are food allergies related to other health conditions?
Heredity may cause a predisposition to have allergies of any type, and repeated exposure to allergens leads to sensitivity in those who are susceptible. Some experts believe that, in rare cases, a specific allergy can be passed from parent to child. Several studies have indicated that exclusive breast-feeding, especially with maternal avoidance of major food allergens, may prevent some food allergies in infants and young children (Smoking during pregnancy may result in an increased likelihood that the baby will suffer from allergies.). Most patients who have true food allergies have other types of allergies, as well, such as dust or pollen, and children with both food allergies and asthma are at increased risk for more severe reactions.
What types of reactions can be expected with food allergies?
The greatest danger posed by food allergies is a reaction called anaphylaxis, a violent allergic response involving a number of parts of the body simultaneously. Similar to less serious allergic reactions, anaphylaxis usually occurs after a person is exposed to an allergen to which he or she has been sensitized by previous exposure (in other words, it does not usually occur the first time a person eats a particular food). Although any food can trigger anaphylaxis (also known as anaphylactic shock), peanuts, tree nuts, shellfish, milk, eggs, and fish are the most common culprits. As small an amount as 1/5 to 1/5000 of a teaspoon of the offending food has caused death.
Anaphylaxis can produce severe symptoms in as few as 5 to 15 minutes, although life-threatening reactions may progress over hours.
Signs of an anaphylactic reaction include:
- difficulty breathing
- a feeling of impending doom
- swelling of the mouth and throat
- a drop in blood pressure
- loss of consciousness
The sooner anaphylaxis is treated the greater the person's chance of survival. A person experiencing anaphylaxis should be taken to the hospital emergency room, even if symptoms appear to be subsiding on their own.
How can severe anaphylaxis be treated?
There is no specific test to predict the likelihood of anaphylaxis, although allergy testing may help determine an individual’s potential allergens and provide some guidance as to the severity of the allergy. Experts advise people who are susceptible to anaphylaxis to carry medication, such as injectable epinephrine, with them at all times and to check the medicine's expiration date regularly. Doctors can instruct patients with allergies on how to self-administer epinephrine. Such prompt treatment can be crucial to survival.
Injectable epinephrine is a synthetic version of a naturally occurring hormone also known as adrenaline. For treatment of an anaphylactic reaction, it is injected directly into a thigh muscle or vein. It works directly on the cardiovascular and respiratory systems, causing rapid constriction of blood vessels, reversing throat swelling, relaxing lung muscles to improve breathing, and stimulating the heartbeat.
Epinephrine designed for emergency home use comes in two forms: a traditional needle and a syringe kit known as Ana-Kit, or an automatic injector system known as Epi-Pen. Epi-Pen's automatic injector design, originally developed for use by military personnel to deliver antidotes for nerve gas, is described by some as "a fat pen." The patient removes the safety cap and pushes the automatic injector tip against the outer thigh until the unit activates. The patient holds the "pen" in place for several seconds, then throws it away. While Epi-Pen delivers one pre-measured dosage, the Ana-Kit provides two doses. Which system to use is a decision to be made by doctor and patient, taking into account the doctor's assessment of the patient's individual needs.
Where can I find more information about my food allergies?
An Internet search will lead you to numerous organizations that provide extensive information about food allergies, as well as support for food allergy sufferers. Information may range from recipes to tips on how to read food labels to current fundraising efforts.
The following is a brief sampling of food allergy websites:
The Food Allergy & Anaphylaxis Network:
If you or a family member has suffered from food poisoning, and you have a question about your legal rights, you can request a free case evaluation from our firm by clicking on free case evaluation. You may also contact us toll free at 1-877-934-6274.
The information contained on this page has been gathered from the websites of the Centers for Disease Control and Prevention, the Food and Drug Administration and other sources in the public domain.