Less restrictive dietary options, better detection, targeted avoidance measures, educational directives and potential new therapies are improving food allergy management and giving hope to the more than 12 million Americans affected according to experts at the thirteenth international food allergy conference held during the annual meeting of the American College of Allergy, Asthma and Immunology (ACAAI) in Miami Beach, Fla.
"The management of food allergy relies primarily on avoidance of exposure to suspected or proven foods," said Alessandro Fiocchi, M.D., director of the Pediatric Department at The Melloni University Hospital in Milan, Italy. "This can best be done if the specific foods responsible for the patient's symptoms are identified by history and appropriate tests."
Not all foods a patient is sensitized to should be eliminated, and not all sensitized patients should be on a diet, said Dr. Fiocchi. Patients may not need to avoid all in a specific food group, such as different kinds of fish for a person with fish allergy.
ACAAI President-Elect and Program Chair Sami L. Bahna, M.D., Dr.P.H., professor of pediatrics & medicine, and chief of allergy & immunology at Louisiana State University Health Sciences Center in Shreveport, La., said food allergy must sometimes be investigated even without an apparent relationship to eating.
Diagnosing Food Allergy
"The allergist must be a good detective in discovering the cause of some reactions, often seeing a patient multiple times to compile a detailed medical and environmental history. Food allergens can be hidden, very minute, or cross-reactive with other food allergens," Dr. Bahna said.
"We have seen cases where food allergy is caused by skin contact or smell, such as an allergy to fish, shellfish, egg or milk. Even a touch can be risky to patients with severe food allergy, especially to peanuts," he said.
An allergist, an expert in the diagnosis and treatment of allergies and asthma, can perform allergy testing to identify the specific food and additives that trigger allergic reactions and determine the most appropriate and effective food allergy management procedures.
Allergists may refer food allergy patients on restricted diets to a dietitian for a nutrition assessment to assure they are getting proper nutrition. Referrals to a dietitian with experience in
food allergy may include patients in the following situations:
•Diagnosis of a food allergy at any age for education on allergen avoidance
•Mother of an allergic child who is breastfeeding and following a restricted diet
•Considering discontinuation of a nutrition formula to an alternative beverage
"Restricting common dietary staples creates potential for nutritionally suboptimal diets," said Mandy Monty, R.D., L.D., Nutrition Therapy at Cincinnati Children's Hospital Medical Center in Cincinnati, Ohio.
A dietitian will review age appropriate portion sizes in an elimination diet and explore alternative sources for calories, protein and nutrients, including calcium. Patients usually benefit from a sample allergen-free meal plan and a list of family resources, Ms. Monty said.
Patients with food allergy must also be educated about the label law titled "Food Allergen and Consumer Protection Act" effective Jan. 1, 2006. The law requires food manufacturers to identify eight major allergens, which are: egg, milk, peanut, tree nut, fish, shellfish, soybean and wheat. Flavorings, additives, colorings and spices are no longer exempt.
Prevalence of Food Allergy
The prevalence of food allergy is 6 percent to 8 percent of young children, and 2 percent to 3 percent of adolescents and adults, and appears to be rising sharply according to Robert A. Wood, M.D., professor of pediatrics & international health, and director, pediatric allergy and immunology, at Johns Hopkins University in Baltimore, Md.
"The prognoses for the resolution of milk, egg, wheat and soy allergy are worse in more recent studies than previously reported," said Dr. Wood. "Whether these findings represent a true change in the natural history of these allergies, or a unique, highly atopic population, remains to be determined. Peanut allergy is less often outgrown, but more often than previously thought," he said.
The loss of food allergy is complete tolerance to a food that previously caused a clinical reaction said Dr. Wesley Burks, MD, professor and chief, pediatric allergy and immunology at Duke University Medicial Center in Durham, N.C. Peanut allergy is outgrown in 20 percent of young children, generally by school age, whereas 60 percent of children outgrow milk, egg, wheat and soy allergies.
Food allergy is the most common cause of visits for anaphylaxis treated in Emergency Departments. Nearly 15 percent of patients per year have accidential reactions.
"Investigations are being conducted on potential therapies for food allergy with the goal of developing an active treatment by means of desentization or increased tolerance to protect patients from accidental exposures," Dr. Burks said.
Treatment options under investigation include allergen non-specific therapies that would be effective for any food allergy include anti-IgE and certain preparations of Chinese herbal medicine.
Studies indicate anti-IgE monoclonal antibody therapy may be effective in 75 percent of patients, but it must be given on a continuous basis, and there are concerns about its safety and cost. Future anti-IgE treatments for food allergy may be utilized in combination with other immunotherapy treatments.
"Herbal remedies used in Asia for centuries are under investigation in the United States. A study of Chinese medicine FAHF-2 used in a mouse model for peanut allergy worked to prevent symptoms of a reaction, and we are seeing favorable results in early human studies," Dr. Burks said.
Therapies that are allergen-specific include heat-denatured protein, sublingual immunotherapy (SLIT), engineered recombinant protein, and oral immunotherapy (OIT).
Investigations into the use of baked or extensively heated food for daily ingestion in certain patients are successfully promoting desensitization and or tolerance to foods, such as milk and egg products.
In food allergy, the risks of traditional immunotherapy (subcutaneous injections of intact allergen) have far outweighed the benefits, but new approaches under investigation look promising.
"Several preliminary studies on oral or sublingual immunotherapy for food allergy have very encouraging results, with strong evidence of at least short term desensitization. Investigators are looking carefully at the safety of dosing and working on establishing initial, build-up and maintenance protocols for peanut allergy," Dr. Burks said.
Using an "engineered" peanut protein in a mouse model of peanut allergy, the "new" proteins worked to help prevent anaphylaxis in the peanut-allergic mice, he noted.
"The work on the development of a treatment for food allergy is progressing rapidly and is very encouraging," Dr. Burks said.