Posted by: Indonesian Children | August 29, 2009

Food Hypersensitivity In Children

 

Definitions

  • ‘Food hypersensitivity’ is defined as an adverse reaction to a food protein that results from an immunologic mechanism. It is important to differentiate food hypersensitivity from ‘food intolerance’ as the management of these conditions is different .
  • Food intolerance refers to an adverse reaction to food caused by a non-immunological mechanism such as a direct pharmacologic effect of a chemical contained within food (Eg: tyramine induced nausea, emesis, headache) or metabolic disorders (Eg: lactase or disaccharidase deficiency).

CLINICAL MANIFESTATION

Clinical Features

Food hypersensitivity reactions may be IgE mediated (“Food Allergy”) or non-IgE mediated.

IgE mediated “allergic” reactions generally occur rapidly upon ingestion of an offending food (within 30min – 1hr) and can involve a number of organ systems – skin, gastrointestinal, respiratory, cardiovascular (Box 3). Most reactions involve the skin or gastrointestinal system with various combinations of urticaria, angioedema, vomiting, diarrhoea and abdominal cramps. Severe IgE mediated reactions can lead to systemic anaphylaxis with involvement of respiratory and/or cardiovascular systems in addition to skin and gut. Such reactions may be fatal. Food allergic reactions rarely cause isolated respiratory symptoms without associated cutaneous reactions. ‘Gastrointestinal anaphylaxis’ may occur in infants with immediate onset of severe vomiting and diarrhoea leading to dehydration and hypotension. IgE mediated food reactions may also be associated with delayed development or exacerbation of eczema. The ‘oral allergy syndrome’ refers to a condition in which allergic symptoms are restricted to the oropharynx, with tingling or swelling of lips and tongue. It is most commonly seen in patients with seasonal allergic rhinitis who report symptoms following ingestion of a variety of fruits and vegetables, and is thought to reflect allergenic cross reactivity between pollens and foods (Eg: birch pollen and apple). Exercise related food reactions may occur following a combination of exercise and ingestion of a food within a given time period, while either exercise or food alone does not cause a reaction. Such exercise related food reactions are frequently severe and can result in anaphylaxis.

Non-IgE mediated hypersensitivity reactions are generally delayed with symptoms developing several hours to days after ingestion of an offending food. They present predominantly with gastrointestinal symptoms. A number of non-IgE mediated food hypersensitivity syndromes have been described

Clinical Features

Food hypersensitivity reactions may be IgE mediated (“Food Allergy”) or non-IgE mediated.

IgE mediated “allergic” reactions generally occur rapidly upon ingestion of an offending food (within 30min – 1hr) and can involve a number of organ systems – skin, gastrointestinal, respiratory, cardiovascular. Most reactions involve the skin or gastrointestinal system with various combinations of urticaria, angioedema, vomiting, diarrhoea and abdominal cramps. Severe IgE mediated reactions can lead to systemic anaphylaxis with involvement of respiratory and/or cardiovascular systems in addition to skin and gut. Such reactions may be fatal. Food allergic reactions rarely cause isolated respiratory symptoms without associated cutaneous reactions. ‘Gastrointestinal anaphylaxis’ may occur in infants with immediate onset of severe vomiting and diarrhoea leading to dehydration and hypotension. IgE mediated food reactions may also be associated with delayed development or exacerbation of eczema. The ‘oral allergy syndrome’ refers to a condition in which allergic symptoms are restricted to the oropharynx, with tingling or swelling of lips and tongue. It is most commonly seen in patients with seasonal allergic rhinitis who report symptoms following ingestion of a variety of fruits and vegetables, and is thought to reflect allergenic cross reactivity between pollens and foods (Eg: birch pollen and apple). Exercise related food reactions may occur following a combination of exercise and ingestion of a food within a given time period, while either exercise or food alone does not cause a reaction. Such exercise related food reactions are frequently severe and can result in anaphylaxis.

Non-IgE mediated hypersensitivity reactions are generally delayed with symptoms developing several hours to days after ingestion of an offending food. They present predominantly with gastrointestinal symptoms. A number of non-IgE mediated food hypersensitivity syndromes have been described

Prevalence

Food hypersensitivity is common, affecting up to 6%of children and 1.5 – 2% of adults

  • . The majority of food hypersensitivity reactions are caused by a small number of foods – egg, milk, peanut/tree nuts, wheat, soy, fish, shellfish. Different foods are more likely to cause allergy at different ages

Clinical Manifestation

  • IgE mediated “allergic” reactions generally occur rapidly upon ingestion of an offending food (within 30min – 1hr) and can involve a number of organ systems – skin, gastrointestinal, respiratory, cardiovascular . Most reactions involve the skin or gastrointestinal system with various combinations of urticaria, angioedema, vomiting, diarrhoea and abdominal cramps. Severe IgE mediated reactions can lead to systemic anaphylaxis with involvement of respiratory and/or cardiovascular systems in addition to skin and gut. Such reactions may be fatal. Food allergic reactions rarely cause isolated respiratory symptoms without associated cutaneous reactions. ‘Gastrointestinal anaphylaxis’ may occur in infants with immediate onset of severe vomiting and diarrhoea leading to dehydration and hypotension. IgE mediated food reactions may also be associated with delayed development or exacerbation of eczema. The ‘oral allergy syndrome’ refers to a condition in which allergic symptoms are restricted to the oropharynx, with tingling or swelling of lips and tongue. It is most commonly seen in patients with seasonal allergic rhinitis who report symptoms following ingestion of a variety of fruits and vegetables, and is thought to reflect allergenic cross reactivity between pollens and foods (Eg: birch pollen and apple). Exercise related food reactions may occur following a combination of exercise and ingestion of a food within a given time period, while either exercise or food alone does not cause a reaction. Such exercise related food reactions are frequently severe and can result in anaphylaxis.
  • Non-IgE mediated hypersensitivity reactions are generally delayed with symptoms developing several hours to days after ingestion of an offending food. They present predominantly with gastrointestinal symptoms. A number of non-IgE mediated food hypersensitivity syndromes have been described

Diagnosis of food hypersensitivity

In most cases, patients should be referred to an allergy specialist who can confirm the diagnosis of food hypersensitivity, determine if hypersensitivity to other foods is present and provide advice regarding further management. History is an important tool in the diagnosis of food allergy and hypersensitivity. History will provide clues to the food causing a reaction and whether the reaction is likely to be IgE mediated or non-IgE mediated. Patients should avoid the implicated food until further evaluation is completed. Careful examination and appropriate investigations should be performed to exclude other causes

In IgE mediated food allergy, diagnosis may be confirmed by skin prick testing or RAST testing. Other methods of testing (Vega tests, pulse tests etc) have not been validated and are not recommended. Skin prick testing is preferred over RAST testing since it is simple, inexpensive, does not require a blood sample and provides immediate results. Results of skin prick and RAST (serum specific IgE) tests must be interpreted with caution. A positive test only demonstrates the presence of specific IgE to the food in question. It does not necessarily indicate the presence of clinical allergy. Less than 50% of individuals with a positive skin test to a food will react to that food upon formal challenge. Thus, if the history is clear, a positive skin test can confirm the diagnosis of IgE mediated food allergy. However, if the history is uncertain, the significance of a positive skin test may need to be confirmed by formal food challenge. A negative skin test on the other hand is very helpful as it almost eliminates the possibility of IgE mediated reaction to the food in question. In cases of suspected IgE mediated food allergy, food challenges must only be performed by a specialist allergist as there is a risk of serious reaction that may be life-threatening.
There are no specific diagnostic tests for non-IgE mediated food hypersensitivity. Diagnosis requires an elimination diet followed by challenge to the suspected food. Endoscopy and biopsy may be helpful particularly in cases of suspected eosinophilic colitis, food induced enteropathy and eosinophilic gastroenteritis.

Diagnosis

  • Patients should be referred to an allergy specialist who can confirm the diagnosis of food hypersensitivity, determine if hypersensitivity to other foods is present and provide advice regarding further management. History is an important tool in the diagnosis of food allergy and hypersensitivity. History will provide clues to the food causing a reaction and whether the reaction is likely to be IgE mediated or non-IgE mediated. Patients should avoid the implicated food until further evaluation is completed. Careful examination and appropriate investigations should be performed to exclude other causes
  •  In IgE mediated food allergy, diagnosis may be confirmed by skin prick testing or RAST testing.
  • Other methods of testing (Vega tests, pulse tests etc) have not been validated and are not recommended.
  • Skin prick testing is preferred over RAST testing since it is simple, inexpensive, does not require a blood sample and provides immediate results. Results of skin prick and RAST (serum specific IgE) tests must be interpreted with caution. A positive test only demonstrates the presence of specific IgE to the food in question. It does not necessarily indicate the presence of clinical allergy. Less than 50% of individuals with a positive skin test to a food will react to that food upon formal challenge. Thus, if the history is clear, a positive skin test can confirm the diagnosis of IgE mediated food allergy. However, if the history is uncertain, the significance of a positive skin test may need to be confirmed by formal food challenge. A negative skin test on the other hand is very helpful as it almost eliminates the possibility of IgE mediated reaction to the food in question. In cases of suspected IgE mediated food allergy, food challenges must only be performed by a specialist allergist as there is a risk of serious reaction that may be life-threatening.
  • There are no specific diagnostic tests for non-IgE mediated food hypersensitivity. Diagnosis requires an elimination diet followed by challenge to the suspected food. Endoscopy and biopsy may be helpful particularly in cases of suspected eosinophilic colitis, food induced enteropathy and eosinophilic gastroenteritis.

Treatment

  • Once a diagnosis of food allergy or food hypersensitivity is established, strict elimination of the offending food is the only treatment available.
  • There is no cure for food allergy at the present time. Elimination of a food requires careful attention to reading ingredient labels. Patients should be educated about “hidden” sources of a food – Eg: egg in cakes and biscuits. Referral to a dietician with a particular interest in food allergy should be considered as part of the management when implementing an elimination diet in children. As most food allergies resolve with time, patients should be reviewed at 1-3 year intervals with repeat skin testing and in some cases challenged to monitor for the development of clinical tolerance. At this time, there is no role for desensitisation therapy for food allergy.
  • All patients with IgE mediated food allergy, particularly those with asthma, should be warned about the possibility of developing severe anaphylactic reaction and should have an appropriate action plan (which may include an adrenaline Epipen) in case of accidental ingestion. In cases of systemic anaphylaxis with generalised symptoms and involvement of respiratory or cardiovascular systems, the first line treatment is adrenaline. Delayed administration of adrenaline was a major factor associated with fatal anaphylaxis. Once adrenaline is administered, corticosteroid and antihistamines may be given and arrangements made for transfer to hospital. Antihistamines may be used for mild allergic reactions confined to the skin. Regular review of an action plan is important as patients may have accidental exposures to the food(s) concerned.

 

References :

  • Sampson HA, Adverse reactions to foods, in Allergy: Principles and Practice, E. Middleton, et al., Editors. 1993, C.V. Mosby: St Louis. p. 1661-1686.
  • Bock SA. Prospective appraisal of complaints of adverse reaction to foods in children during the first 3 years of life. Pediatr 1987;79:683-688.

 

 

Provided by
children’s ALLERGY CLINIC

JL TAMAN BENDUNGAN ASAHAN 5 JAKARTA PUSAT, JAKARTA INDONESIA 10210

PHONE : (021) 70081995 – 5703646

htpp://www.childrenallergyclinic.wordpress.com/ 

 

Clinical and Editor in Chief :

WIDODO JUDARWANTO

email : judarwanto@gmail.com,

 

 

Information on this web site is provided for informational purposes only and is not a substitute for professional medical advice. You should not use the information on this web site for diagnosing or treating a medical or health condition. You should carefully read all product packaging. If you have or suspect you have a medical problem, promptly contact your professional healthcare provider.

Copyright © 2009, Children Allergy Clinic Information Education Network. All rights reserved.


Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

Categories

%d bloggers like this: