What is a food allergy definition

What is food allergy?

Food allergy, which affects 1-2% of adults and 6-8% of children in the US, is defined as an immediate adverse reaction to components found in food products. The allergic reaction is caused by pre-formed antibodies to food components which bind to special cells in the bloodstream, releasing chemicals which cause symptoms of an allergic reaction.

How is food allergy diagnosed?

Since reactions can be life-threatening, immediate diagnosis and treatment of food allergy is extremely significant. Allergies to food can be diagnosed at your allergist’s office by skin prick testing. This painless method involves putting a extremely little quantity of each food allergen just under the skin, with results available in 15 minutes.

Sometimes, physicians measure allergy antibodies in the blood to diagnose and follow patients with food allergy. The best test for food allergy, however, is to act out a “food challenge”, where the suspected food is eaten in increasing amounts under shut supervision at an allergist’s office. It is significant to note that allergies change over time, and new allergies can appear at any time regardless of age, so it is best to consult your allergist if you own any new reactions or concerns about food.

What are the symptoms of food allergy?

Symptoms of food allergy can include hives, vomiting, stomach pain, dizziness, mouth/tongue and throat itching, and can even manifest as difficulty breathing, throat swelling, and in severe cases, coma and death.

What are some common food allergens for children and adults?

The most common allergenic foods for young children are milk, egg, soy, and wheat.

Food allergy in adults is most commonly caused by peanut, tree nut, fish and shellfish. Approximately 80% of young children outgrow allergies to milk and egg; however, only 20% of patients with nut and shellfish allergies lose their allergic reactions over time.

How is food allergy treated?

Currently, treatment for food allergy is strict avoidance of the offending food. This involves reading ingredient labels and being extremely careful when dining exterior of the home.

Symptoms of an allergic reaction should be treated with injectable epinephrine, also known as an EpiPen, which should be carried at every times. In some cases, Benadryl can be used for mild reactions. There is new and exciting research in the field of food allergy which may eventually lead to a cure for both children and adults, however none of these therapies are approved at the present time.

If you suspect that you or your kid may own a food allergy, come and visit your allergist — we can help!

— By Dr. Katharine S.

Nelson

Board Certifications

  1. American Board of Allergy and Immunology
  2. American Board of Pediatrics


Biography

Dr. Nicole Chadha received her B.A. in psychology from the University of Kansas, then returned to her southern roots in Georgia to pursue her career in medicine. She graduated with her medical degree from the Medical College of Georgia in Augusta, GA. She subsequently completed her pediatric residency at Palmetto Health Richland Children’s Hospital associated with the University of South Carolina and fellowship in Allergy/Immunology at Vanderbilt University.
Upon completion of her fellowship, Dr.

Chadha remained on faculty at Vanderbilt as an Assistant Professor within the Division of Pediatric Allergy, Immunology, and Pulmonary Medicine. Dr. Chadha is board certified in Pediatrics and Allergy and Immunology. She is a member of the American Academy of Allergy, Asthma, and Immunology, and the American College of Asthma Allergy and Immunology.

Dr. Chadha chose to specialize in Allergy in specific because she enjoys studying the intricacies of the immune system and likes that the specialty allows her to treat both children and adults. The chronic nature of allergic disease affords her the chance to build lasting relationships with her patients.

She finds grand reward in providing care and education that results in an improved quality of life for her patients. Dr. Chadha has numerous interests in a variety of allergic and immunologic conditions, including food allergy, asthma, urticaria, allergic rhinitis, primary immunodeficiency and eosinophilic esophagitis. She has contributed to research on eosinophilic esophagitis in children and has presented her work both locally and nationally.

Dr. Chadha lives in Charlotte with her husband, Ashley, a pediatric pulmonologist, 2 young sons, and 2 dogs. In her free time, she enjoys traveling, reading, cooking, interior design, volunteering and taking part in community events.

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The term cutaneous adverse food reaction (food allergy) is often used to define the food-triggered clinical syndrome of allergic dermatitis, gastrointestinal (GI) signs or both.

Food allergies may be responsible for chronic skin and ear disease in both cats and dogs.

Potential allergens can include protein sources (e.g. chicken, turkey, beef, lamb, soy, dairy, eggs) or carbohydrate sources (e.g. corn, rice, barley, wheat). Some pets can own more than one food allergy. Food allergies often start in pets younger than 1 or older than 7 years of age, but they can be acquired at any time, even when a pet has been eating the same food for months to years.

What does food allergy glance like?

Food-allergic animals generally own nonseasonal pruritus because the source of the problem does not change with the weather or seasons.

About 20% of food-allergic pets also own GI signs such as flatulence, vomiting, diarrhea, noisy intestinal sounds, or defecating more than four to five times a day. Dogs may scratch their face, ears, feet, groin or anal area or develop recurrent skin or ear infections (Figure 1). A frequent presentation includes licking at the anal area in addition to problems with the ears-this is why the condition is often referred to as one that affects “ears and rears.” Cats may overgroom certain areas of the body or the whole body, exhibit intense itching at the face or neck, or develop ear infections.

Figure 1. Skin infections in a food-allergic cat (top) and dog (bottom). Images courtesy of Judy Seltzer, BVetMed, MRCVS, DACVDThe onset of food allergy can be slow and gradual or more sudden.

Clinical signs often continue to progress as endless as the offending allergen is fed. It can take several weeks to months for clinical signs to resolve once the allergenic agent is removed from the animal's diet. Up to 30% of food-allergic pets may own other allergies, such as a flea allergy dermatitis or atopy (environmental allergies). About 50% of food-allergic dogs will not reply favorably to steroids.

Diagnosis and treatment of food allergy

The only precise way to diagnose an animal with a food allergy is to remove all of the currently fed foods and start a strict elimination diet trial.

Available blood and saliva tests are not dependable for diagnosing food allergies in cats and dogs, and skin testing has also been found to be ineffective.

An elimination diet consists of a prescribed home-cooked or prescription therapeutic diet that contains a unique protein and carbohydrate source to which the animal has not previously been exposed. The most common novel protein diets include rabbit and potato, venison and potato, and kangaroo and oats. Numerous fish and lamb diets are no longer considered novel as these ingredients are more commonly used in over-the-counter (OTC) diets.

Another option is to use a hydrolyzed (low-molecular-weight) diet, also available by prescription.

What is a food allergy definition

These diets are composed of common ingredients (such as chicken and soy) that own been molecularly altered to be under the allergenic threshold. This alteration prevents the animal's immune system from recognizing the food.

Oh, no, you didn't

Simply changing from one brand of pet food to another does not constitute an allergy diet trial. Several OTC “allergy” or “limited-ingredient” diets are now available in pet stores and online, but they are not always as pure as they claim to be or may own hidden ingredients.

Some pets with food allergies will not get better on a pet store diet.

What is a food allergy definition

A little percentage of truly food-allergic animals remain undiagnosed with commercially prepared diets and need to be trialed with a home-cooked diet.

Home-cooked diets. Examples of proteins used in home-cooked diets are tilapia, salmon, duck, rabbit, pork or pinto beans, generally mixed with sweet potatoes, oats, quinoa or barley. A home-cooked diet should be nutritionally balanced. Therefore, recommend that the client consult with a board-certified nutritionist before feeding a home-cooked diet.

Nutritionists are also extremely helpful when an animal has a concurrent disease, such as urinary tract infection, history of bladder stones or irritable bowel disease, and they can work with the primary veterinarian or dermatologist to formulate an appropriate diet. Websites including balanceit.com and raynenutrition.com own also been helpful in formulating home-cooked diets for a trial.

Therapeutic diets. Veterinary dermatologists often prescribe therapeutic diets from Royal Canin, Hill's and Purina for use in elimination trials.

In addition, Rayne Clinical Nutrition makes rabbit, kangaroo and pork diets for dogs and cats that are less processed than dry kibble or canned foods. Selecting a diet will depend on your patient's diet history. Furthermore, some cats and dogs will require a wet food to assist ister medications, and some owners are adamant about having treats to feed their pet. Knowing the needs of your patient and client will assist in choosing the most appropriate diet for your patient.

Did we mention elimination diet trials are strict?

Emphasizing to clients that absolutely no other food products or treats should be given during an elimination diet trial is imperative.

The pet should be allowed to consume only the prescribed diet, associated treats and water. Pets in an elimination trial cannot have:

Table food

Rawhides, pig ears, bones or other chew toys made with animal products

Supplemental fatty acids

Parasite preventives, medications or toothpastes with added flavor

Treats used to ister medications (e.g. peanut butter, cream cheese, lunch meat, pill pockets).

Regardless of which elimination diet is selected, it should be introduced gradually over a five- to seven-day period. This is extremely significant as some animals may develop GI problems if their diet is changed suddenly.

Most pets adapt to the new diet well, but some need time to adjust. If the pet doesn't adjust to the new diet within a week or two or refuses multiple therapeutic diets, a home-cooked diet can be formulated with the assist of a veterinary nutritionist. To formulate the best possible plan for your patient, it is also significant to take into consideration challenges such as households with multiple pets or little children.

The elimination trial should continue for at least eight to 12 weeks and a minimum of one month beyond resolution of a skin infection. The pet should be rechecked frequently to assess the progress and results of the diet trial.

Rechecks may be more frequent if the pet is being treated for an athletic infection.

If the pet has a food allergy, we expect to see at least a 50% reduction in licking, scratching, chewing or other dermatologic signs. This may happen within the first four weeks for some animals; in others the response may take up to 12 weeks. Cats may need to be on the elimination diet for three to four months before a food allergy is confirmed.

The diet challenge

To prove that a food allergy is responsible for a pet's condition, a diet challenge is typically performed.

This involves reintroducing the original diet, or ingredients from the original diet, to see if the pet has any reaction. In the food-allergic pet, clinical signs will generally worsen within hours to two weeks. If an adverse reaction occurs, resume the elimination diet exclusively. Once the flare-up is resolved, reintroduce individual ingredients from the previous diet one at a time to identify the specific cause.

Beyond proving the food allergy diagnosis precise, a food challenge helps to determine which specific foods or treats should be avoided and to identify an OTC diet that the pet can tolerate.

If we can determine the ingredient causing the problem, we can manage the condition by eliminating the offending food(s) from the pet's diet for life.

Keep in mind, however, that this may not always be possible. Some patients may need to remain on a therapeutic or home-cooked diet for life. Feeding a therapeutic diet long-term will not harm a pet because these diets are well balanced. Therapeutic diets tend to be more expensive than OTC diets, however, and numerous owners prefer to feed a commercial diet.

Prognosis

As with other types of allergies, there is no cure for food allergy.

What's more, animals can develop new food allergies over time. However, if a food allergy is the sole cause of a pet's skin or ear problems, identifying and eliminating the protein(s) or carbohydrate(s) causing the allergy may significantly increase the pet's quality of life and reduce or prevent skin and ear problems in the future.

As noted earlier, pets with an allergy to food ingredients are at higher risk for developing other allergies such as atopic dermatitis or flea allergy dermatitis.

To hold under an animal's itch threshold, every food-allergic pets should be maintained with strict flea control and monitored for secondary skin infections and itching.

Dr. Judy Seltzer graduated from the Royal Veterinary College in London and completed her residency in dermatology at the University of Florida. She has been working in her home state of New York since 2009, currently at BluePearl Veterinary Partners in New York City.

She and her husband own a little girl and four cats and enjoy traveling, drop festivals, winter activities and dining out.

“This discovery reverses food allergies in mice, and we own numerous people with allergies volunteering their own cells for us to use in lab testing to move this research forward,” said professor John Gordon, lead scientist behind the discovery just published in the current issue of the Journal of Allergy and Clinical Immunology.

The findings open the door to test this new allergy treatment in “humanized mice”—mice with non-existent immune systems implanted with cells from a human immune system, for example, from a peanut-allergic person.

With Health Canada approval, the first human trial could start in about one year, Gordon said. 

“If we can reliably ‘cure’ food allergies, or related conditions such as asthma or autoimmune diseases such as multiple sclerosis with this new therapy, it would be life-changing for affected individuals.”

Roughly 2.5 million Canadians self-report having at least one food allergy.  Anaphylaxis, defined as a severe rapid-onset allergic reaction, can be life-threatening and treatment options are limited.

The discovery involves generating a type of naturally occurring immune cell that sends a signal to reverse the hyper-immune response present in allergic reactions.  That signal triggers another “off switch” that turns off reactive cells further along the allergic pathway. 

“We predict the treatment could be on the market within the next five to 10 years,” said Gordon, who is also a research leader in the Allergy, Genes and Environment (AllerGen) Network.

AllerGen—part of the federally funded Networks of Centres of Excellence program—aims to assist Canadians address the challenges of living with asthma, allergies, anaphylaxis and related immune diseases.

Gordon’s team will collaborate with other AllerGen investigators located at the U of S, McGill University, Queen’s University, McMaster University, and University of Alberta to pilot the new technique.

“This discovery portends a major breakthrough towards a therapeutic reversal of food allergen sensitivity,” said Dr.

What is a food allergy definition

Judah Denburg, scientific director and CEO of AllerGen. “The treatment prevents anaphylactic responses in what were previously fully sensitive mice, opening the door for translating this therapy into the clinic.”

There is compelling evidence this technique could be effective in humans.  In 2010, Gordon’s team demonstrated they could reverse an asthmatic response in human cells in a test tube. Using three applications of a similar therapy in a 2012 study, the researchers effectively eliminated asthma in afflicted mice, within only eight weeks.

“Even if we only cure 25 per cent of subjects, we will dramatically improve the health of those individuals, and also reduce healthcare system expenses,” said Gordon, who worked with Wojciech Dawicki, a research associate and the primary author and lead researcher in this study.

Master’s student Chunyan Li and lab technicians Xiaobei Zhang and Jennifer Town also worked on the project.

Here’s how the technique works:

  1. The key component of this research is dendritic cells, which serve as the gate-keepers of the immune system and are present in tissues in contact with the external environment, such as the skin and the inner lining of the nose, lungs, stomach and intestines.
  2. Gordon’s pioneering treatment involves producing dendritic cells in a test tube and then exposing them to a unique stir of proteins, a vitamin A-related acid naturally occurring in the human gut, and to the allergen, in this case, peanut or ovalbumin (egg white protein).

    The modified dendritic cells are then reintroduced into the mouse. 

  3. Using this technique, the researchers were capable to almost eliminate the allergic reaction by converting allergen-sensitive immune cells into cells that mimic the response seen in healthy, non-allergic individuals.  

The treatment reduced the observed symptoms of anaphylaxis, and lowered other key protein markers in the allergic response by up to 90 per cent.

Food allergy is a growing public health issue in Canada.

Currently, there is no known cure. According to the Canadian Institute for Health Information, an estimated 171,000 Canadians visited emergency rooms for allergic reactions from 2013 to 2014, the rate of anaphylaxis visits increased by 95 per cent from 2006 to 2014, and the severity of reactions is increasing.

Gordon said the new technique also shows promise for treating autoimmune disorders such as multiple sclerosis. “It would take extremely little to adapt the therapy for autoimmune diseases,” he said.

Funding for the research was provided by the Canadian Institutes of Health Research and the AllerGen Networks of Centres of Excellence.

 

Last Saturday, a day after the opening of “Peter Rabbit,” Will Gluck’s new and free adaptation of Beatrix Potter’s stories, Kenneth Mendez, the president and C.E.O.

of the Asthma and Allergy Foundation of America, issued both a statement on and an open letter criticizing the film’s makers and its studio, Sony, for one specific scene. In that scene, Peter and the four other rabbits, who are being threatened and pursued by Tom McGregor (the heir to the venerable Mr. McGregor’s garden), adopt a new strategy to fight him: knowing that he’s allergic to blackberries, they use a slingshot to shoot blackberries at him, and one goes directly into his open mouth. He begins to choke, feels an anaphylactic episode coming on, reaches into his pocket for his EpiPen, injects himself with it, and keels over in exhaustion.

The Asthma and Allergy Foundation criticized the filmmakers for making light of a life-threatening allergy and for depicting the use of an allergen as a weapon against a gravely allergic person.

The statement warned that the movie could be “disturbing” to children with serious allergies; some people advocated a boycott. In response, Sony offered an apology. As a parent of children with severe food allergies, I wish I’d seen the movie before the controversy broke out, because I’d be curious to see whether I would own reacted strongly to the scene without having been alerted to it beforehand. Under the given circumstances, I found that I consent that the scene spotlights an unpleasant insensitivity, even an ugly obliviousness, on the part of the filmmakers.

Yet, even more, it throws into sharp relief the over-all tone and import of the film, and, in the process, reveals other peculiarities that make “Peter Rabbit” exemplary of recent movies and of the times.

“Peter Rabbit” is a boisterous comedy in which live action (human characters in realistic homes, landscapes, and towns) is blended with C.G.I. as seamlessly and as persuasively as in “Paddington 2.” The film was made by a comedy director (Gluck directed “Easy A” and “Friends with Benefits”) who, in the script, which he co-wrote with Rob Lieber, has taken extreme liberties with Potter’s stories.

Peter and his family live in a hollow beneath a tree in rural Windermere, England, and gleefully filch produce from the garden of their nemesis, the elderly Mr. McGregor. When Mr. McGregor suddenly dies, the home and garden are inherited by his great-nephew Tom (Domhnall Gleeson), a Londoner and a tidy freak who is even more hostile to the rabbits than Mr. McGregor was. But his battles against them are inhibited when he makes the acquaintance of his neighbor Bea (Rose Byrne), an artist who is the rabbits’ defender and protector (and also their portraitist).

What is a food allergy definition

Bea and Tom drop in love; knowing that Bea also loves the rabbits—and, especially, their ringleader and brightest personality, Peter—Tom has to do his rabbit hunting on the sly.

Peter and the other rabbits take advantage of Tom’s self-enforced restraint to run rampage through his garden and make his life miserable; Tom, for his part, stealthily takes increasingly forceful action against them. That’s when, facing genuine harm, the rabbits prepare to unleash the blackberry attack, knowing full well its potential consequences. Peter calls it “the endgame.” For that matter, a bit earlier, as they plan the attack, the other rabbits are hesitant; Peter’s mild-mannered cousin Benjamin says that “allergies are serious” and adds, “I don’t desire to get any letters.” (The line wasn’t inserted into the movie after the controversy arose; it was always there.)

What’s peculiar about “Peter Rabbit” is that, along with its quippy, often self-referential humor and plentiful (often clever) visual gags, it features an unusual quantity and degree of violence, which link it to classic-era Looney Tunes cartoons and Three Stooges shorts.

When the elderly Mr. McGregor keels over, Peter examines him by poking his eyeball—and, after declaring him dead, gleefully takes credit for killing him. (Mr. McGregor actually died of a heart attack.) Tom comes slamming at the rabbits with rakes, hoes, and other garden tools. He installs an electric fence against the animal intruders, only to own the rabbits rewire it, electrifying his doorknobs with shocks that blast him, cannonball-like, against hard rock walls. The rabbits plant snapping traps and rakes around Tom’s bed, leading to pinchings and clobberings; they leave various fruits on staircase landings, sending Tom tumbling below.

There’s a repeated gag in which one of the sisters enjoys taking a hard drop and breaking one rib after another, and a climactic bit, involving dynamite, that’s almost apocalyptic.

In another sense, though, the tale owes nothing to the action-heavy, character-thin antics of Bugs Rabbit or Daffy Duck, Elmer Fudd or Road Runner and Wile E. Coyote. Rather, Gluck’s “Peter Rabbit” is thoroughly composed and intricately characterized; the rabbits, no less than the humans, are given elaborate backstories and large emotional arcs that the plot is devoted, at length, to illustrating, explicating, and resolving. Peter and his sisters—Flopsy, Mopsy, and Cottontail—are orphans; their dad was killed and eaten by Mr.

McGregor, and Peter’s familiar blue jacket is actually his father’s. Their mom died, too, making Bea is the closest thing to a parent that the rabbits have.

Meanwhile, Peter is a mischievous, temperamental, vain, proud hothead, who, in a peaceful moment, acknowledges that it’s his “character flaw” to do “stupid and reckless” things. (Oddly enough—or perhaps not oddly at every, given that the movie is written by two men—Bea is given the least backstory.) When romance blooms between Bea and Tom, Peter’s response is partly one of a practical worry for the rabbits’ safety.

What is a food allergy definition

But, as the violence ramps up between Tom and Peter, even Benjamin wonders whether Peter has an ulterior motive—jealousy. In other words, with Bea as Peter’s virtual mom, “Peter Rabbit” is something of a tale about Peter trying to come to terms with a stepfather; the comedic drama links Peter’s mean streak to his emotional deprivation and trauma, and it takes him carefully through the paces of his rise to self-recognition and maturity.

It is precisely this strain of emotional realism that makes the allergy subplot, slight though it is, so repellent. The movie’s other varieties of violence are exaggerated, cartoonish, not just in depiction but in substance.

What is a food allergy definition

Few kids own experience with electrical engineering or own dynamite at home; most kids know other kids with severe allergies. (Despite its explosive extremes and intricate, Rube Goldberg-esque calculation, there are no guns and no knives; Gluck clearly knows that certain things aren’t to be trifled with.) Meanwhile, the same emotional realism turns “Peter Rabbit” didactic, dutiful, tedious.

What is a food allergy definition

Its mechanistic moralism, seemingly distilled from screenwriting classes and studio notes, is the sort that marks so numerous movies now—ones for adults as well as those for children—imparting values in the form of equation-like talking points, which prepare viewers not for life but for more, and similarly narrow, viewing.

Gluck clearly relishes the slapstick action that the characters incite, the situations inspire, and the technology enables, and he invests it with his own sense of exuberant discovery, which is minor but authentic.

When it comes to life lessons, however, he dons his official cap and, far from doing any learning in the course of the action, merely dispenses the official line. That’s why the scene involving a life-threatening allergy is every the more conspicuous: while the relax of the movie marches in lockstep with its edifying narrative, that scene is out of put.

What is a food allergy definition

It doesn’t follow the script.


Education

  1. Fellowship: Vanderbilt University, Allergy/Immunology
  2. Medical School: Medical College of Georgia
  3. Residency: University of South Carolina, Palmetto Health Richland Children’s Hospital
  4. College: University of Kansas, B.A., Psychology


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