Mar 7, 2011

Food Allergies


Although allergic reactions are reproducible -- the same specific food will cause an allergic reaction each time it is eaten -- the specific symptoms can be unpredictable. Many things can make reactions "worse than usual." Some of these factors have to do with the way the person with food allergy encounters the problem food, including the route (contact or ingestion), the amount he or she encounters and the type of preparation.
Some contributing factors are things we may not associate with food allergy such as exercise, colds and other infections, alcohol, NSAIDS (non-steroid anti-inflammatory drugs such as ibuprofen, aspirin or naproxen), hormonal variation, as well as physical and emotional stress.

Importantly, the overall health of the person, including other allergic issues such as asthma, eczema or chronic sinus congestion, can also affect severity of reactions. New medications started for heart problems, anxiety or glaucoma can also affect the specifics of your food allergy reactions and response to epinephrine.

That's why it is important to follow these three rules at all times: 1) always carry your epinephrine auto-injector with you; 2) tell people around you about your allergies and what they can do in the event of an emergency before problems happen; and 3) seek help as soon as you experience any symptoms of food allergy.

Finally, remember to call 911 after you use your epinephrine auto-injector, even if you feel much better. Some people require repeated doses of epinephrine. As many as 1-in-4 people with severe food-allergy reactions have a late re occurrence of symptoms one or more hours after the first reaction.

Most people who get into trouble with severe allergic reactions to foods are teenagers. This is probably because adolescence is a time for many risk-taking behaviours, as well as a time in which people "want to be like everyone else." If you are thinking about trying a food you are allergic to, or not taking your epinephrine auto-injector with you, talk to your allergist and family about your feelings. Testing, including a carefully supervised food challenge, can be performed to find out if your allergies are still active.

Policies to reduce the accidental ingestions of an avoided food and to educate the staff and the students about the signs and treatment of anaphylaxis significantly improve the safety of children with food allergy. With these policies and individualised healthcare plans, children at risk for anaphylaxis can enjoy a safe and healthy learning environment. You can and should meet with the principal of the school and the school nurse, or head of the day-care at the beginning of the school year to review both the school policy and your child's specific needs.

Diagnosing and managing a food allergy in an infant or toddler can be challenging. It is difficult to know exactly what symptoms the child is experiencing, and tests are not as reliable for children less than 2 years of age. Also, once a food allergy has been identified, it can be anxiety provoking to introduce new foods. Nursing mothers of children with food allergies and eczema often follow strict elimination diets, and these can raise concerns regarding whether the nutritional needs of both the mother and child are being met.

For infants in families with food allergy, timing the introduction of foods may be a difficult decision. Prior recommendations suggested delaying the introduction of high-risk foods like peanut until 3 years of age. However, this suggestion has changed because we are no longer sure that avoidance is the best approach. In fact, the LEAP study is a large, on-going study in the United Kingdom to determine which approach is associated with less peanut allergy: extended avoidance or the early introduction of peanut in high doses. Current guidelines from U.S.-based paediatric allergists recommend delaying solids until about 4-to-6 months. Beyond this age, there are no further recommendations to delay the introduction of "at-risk foods." If several members of your family have food allergies, environmental allergies and/or asthma, you may want to talk to an allergist about the changes in these recommendations.

woman holding pill bottles The field of food allergy is changing quickly, and there will be more options for therapy besides avoidance and epinephrine in the near future. Many of these new therapies will be available earlier for individuals who are interested in participating in clinical research studies.

Treatment with epinephrine is a specific concern for older adults with food allergy and anaphylaxis for two main reasons. People in this age group are more likely to experience serious cardiac side effects from epinephrine. Additionally, many people in this age group require systemic therapy with "beta blockers" for cardiac disease and/or topical therapy for glaucoma. Beta blockers, even when applied topically to the eye, can reduce the benefit of epinephrine for acute anaphylaxis.

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