One of the greatest fears a parent may face is whether their child can become seriously ill if he/she comes in contact with a food, such as peanuts, to which their child is allergic. Television and newspapers report numerous stories of a child having to be rushed to an emergency room for treatment because the child was exposed to a food at home, at a friend’s house, or in a restaurant, that resulted in an allergic (anaphylactic) reaction. Food allergies are a growing problem for pediatric patients and their families. While the incidence of food allergies in the general population is about 2%, there is a much higher incidence in pediatric patients with approximately 6-8% of children manifesting some type of sensitivity to a food. Most of these pediatric sufferers are under the age of 5 years. It is estimated that one quarter of households in the United States alter their dietary habits to some extent to accommodate a family member with a presumed food allergy. The manifestations of food allergic reactions range from mild throat and skin irritation to life-threatening anaphylaxis.
Food allergy is by far the most common cause of anaphylaxis seen in the emergency department. An estimated 30,000 emergency department visits and 200 deaths each year are attributed to food-induced anaphylaxis. Of anaphylaxis induced by food allergy, peanuts and tree nuts account for 80%. Trends have shown that the prevalence of peanut allergy has actually doubled within the last decade. Food allergy is very prevalent in children with eczema. It is estimated that 35% of children with moderate to severe eczema have IgE mediated food allergy that may be a triggering factor in their exacerbations.
Although awareness of food allergies in the population has increased, considerable confusion still exists in regard to defining it. The layperson often has only a limited understanding of the term and will refer to any form of food intolerance as an allergy. In many cases a parent may attribute the fact that a child simply does not like a food to the child having an allergy to it. Parents, nutritionists, and even physicians implicate “allergies” for behavioral problems such as Attention Deficit Disorder, poor performance at school, and even Autism. However to date, no study has been able to elicit a definite relationship between food allergy and any of these syndromes listed above.
When by careful history it is established that the child is indeed having a reaction to a food, it then must be determined if the reaction is Type I or IgE mediated (anaphylactic), induced by a non-IgE mediated reaction (anaphylactoid), or non-immune related (idiosyncratic reaction). Examples of idiosyncratic reactions to foods include individuals who develop headaches (Migraines) after eating foods rich in additives such as nitrites. Type I or IgE mediated reactions can be detected by skin or RAST testing. The diagnosis of non-IgE mediated reactions cannot be detected by conventional allergy testing. The only means to make a diagnosis in respect to non-IgE dependent food allergy is by oral provocation challenge, usually done in an office or hospital setting. Oral provocation challenge testing while effective, is time-consuming and not without risk.
Chicken, eggs, cow’s milk protein, peanuts, tree nuts, fish, and soy protein cause the vast majority of food reactions in children living in the United States. Delaying exposure to these foods may delay the development of clinical atopy, and decrease the severity of the allergic (atopic) state in children. However no study to date have been able to demonstrate that delaying the introduction of these foods will completely prevent the allergic state in infants, children, and adults.
Breastfeeding, regardless of the mother’s diet has been proven to be beneficial to the health of the infant. Exclusive breastfeeding for at least 6 months compared with cow’s milk protein formula feedings provides a long-term protective effect on the development of respiratory allergy in the pediatric patient. In subgroups of neonates with a family history suggestive of allergy (atopy), it has been demonstrated that early exposure to cow’s milk protein compared with breast milk increased the risk of developing eczema by age 18 months. The best recommendations for mothers of high-risk infants at this time are to breastfeed for at least 4-6 m
When it is time for the parents to consider adding solid foods to the high-risk infant’s diet, the least allergenic foods should be given first. Cow’s milk protein should not be added until 9-12 months, eggs at 12 months, and peanuts, nuts, and fish at 3 years. Adding solid foods to the infant’s diet in the first 4 months of life is not recommended and has been shown to predispose high-risk infants to eczema. It should be stressed that many children, despite preventive efforts, will still develop food allergies and clinical atopy.
Allergic disease has many different manifestations in children. Symptoms seen in IgE dependent food reactions include oral-pharyngeal irritation with pruritus, urticarial (hives), angioedema (swelling), laryngeoedema, bronchospasm, and gastrointestinal symptoms such as diarrhea, vomiting, pain, and cramping. We have recently seen a new syndrome, Eosinophilic Esophagitis that can present with dysphagia. The most feared consequence of IgE dependent food allergy is anaphylaxis or a generalized allergic reaction that can be life-threatening.
The diagnosis of food allergy is dependent upon a careful history, physical examination, and laboratory tests. The history should be a means in which the physician, patient, and family can begin to identify the foods in question which are thought to be triggering factors. At times the physician may request that the family keep a detailed dietary history. For a definitive diagnosis of IgE dependent food allergy skin or RAST testing should be done. Skin tests are highly reproducible, they have a positive predictive value around 50%, and their negative predictive value is greater than 95%. It is important to note that a positive skin or RAST test alone does not establish the diagnosis of food allergy. To make the diagnosis of IgE dependent food allergy the presence or absence of positive tests should correlate with the patient’s history. When there is a question, the physician may then proceed to oral provocation challenge testing to the food(s) in question. Because of this when there is any doubt in regards to food intolerance/allergy, referral to a physician who specializes in food allergy such as an Allergist/Immunologist would be of benefit.
The prognosis for children who suffer from certain food allergies is generally good. Many patients diagnosed with anaphylaxis to milk, wheat, eggs, and soybean will outgrow their clinical sensitivity. An estimated 50% of cases resolve by 18 months and 90% by 36 months. Children who develop food sensitivity after age 3 are less likely to lose their food sensitivity. However in the case of sensitivity to peanuts, tree nuts, fish, and shellfish the chances of the child going into remission are significantly less, and in fact, the sensitivities to these foods may persist into adult life.
Peanut/Tree Nuts are responsible for the majority of food-induced anaphylaxis cases seen in the emergency department in the United States. It is important for physicians to educate families about the management of peanut/tree nut allergy. Specifically, physicians should teach their patients to read food labels to see if peanuts or tree nuts have been added. Generally if a member of the family is allergic to peanuts/tree nuts, these foods should not be kept in the home. If they are in the home, they should have brightly colored warning labels and be out of reach of the pediatric patient. Restaurants and carry-out establishments should be contacted ahead of time and asked if they use peanuts, tree nuts, or cold-pressed peanut oil in their cooking. The treatment of choice for anaphylaxis is injectable epinephrine. Because of this an Epi-Pen should be carried at all times by the patient, and if necessary a school-nurse. Many schools will establish peanut/tree nut free areas in the school cafeteria. Some airlines are no longer serving peanuts to their passengers. The growing consensus is that an Epi-Pen should be available in all schools and even in restaurants.
It is important to recognize that these changes and restrictions require a lot of work by the family and can cause considerable stress and frustration. In peanut allergic patients, it is often not necessary to restrict other legumes. However, tree nuts are universally restricted due to cross-reactivity unless a particular nut has been individually tested and found to be safe for the patient.
Food allergy in the pediatric population can be difficult to diagnose and manage. While there is ongoing research in the field, other than dietary elimination, there are no other effective treatment modalities. While Immunotherapy has been found to be effective for the treatment of asthma and pollinosis, current studies do not reveal any benefit to the use of allergy injections for food allergy. Other treatment modalities such as food drops have also not been shown to be of any benefit. Hopefully in the future, agents such as Xolair (omalizumab) may be of benefit to reduce or eliminate an individual’s sensitivity to foods. Because of the difficulty in making a diagnosis and the serious implications of food, allergy referral to a physician specialist in the field of Allergy/Immunology will be of much benefit in the diagnosis and management of the child with food sensitivity.
Jessie Rosenberg graduated with a Bachelor of Science degree from Cornell University. She attended medical school at St. Georges University, Grenada where she graduated with a MD. Jessie Rosenberg is currently doing an internship in Pediatrics at the University of Maryland, School of Medicine, Baltimore, Maryland.
Steven Rosenberg has been in private practice in the Central Florida area for over 30 years. His practice, Allergy and Asthma Associates of Central Florida specializes in Pediatric and Adult Allergy, Asthma, and Immunology. Dr. Rosenberg and his associate, Carlos Jacinto, MD, have offices in the Dr. Philips, Winter Park, Altamonte Springs, and Viera.
By Jessie Rosenberg, MD and Steven Rosenberg, MD