Circle of Clinical and Biological Investigations in Food Allergy

 

> USEFUL INFORMATIONS

July 2007
FALSE BELIEFS :

"Infantile atopic dermatitis is a skin disease and is not related to allergy."
This is wrong since infantile atopic dermatitis occurs in the event of one, or several, food allergies. However, it is true that food allergy may disappear over time, but other sensitizations will appear, and may replace food allergens in sustaining atopic dermatitis. It is also true that the skin of patients with atopic dermatitis is different, and even if allergy is not detected, any lesions in skin folds will not disappear (elbow folds, the back of the knees, wrists, neck folds, folds behind the ears and under eyelids, etc.). "My child is too young to have allergy tests."
This is a grave error. After 3 months of age, most infants can undergo skin tests. Under 3 months of age, two thirds of the infant population can undergo skin tests. Onset of allergy can occur at a very early age: between 15 days and one month, but by the time children see an allergologist, they may be 3 months old. Early diagnos
is of food allergy helps manage the disorder, and symptoms will resolve all the quicker if effective treatment is implemented."

"When an infant has an allergy, it is nearly always caused by milk. All I need to do is follow the pediatrician's prescription and give my baby a milk substitute. If symptoms resolve, the diagnosis was correct and my baby needs no further allergy tests."
This is true... and not true. It all depends on the intensity of symptoms. If these are moderate gastrointestinal disorders, we know that the child will recover naturally, usually between the age of 10 to 15 months. In this case allergy tests need not be performed. But if symptoms are more serious, or if the clinical picture resembles atopic dermatitis, allergy tests should be carried out. Results can then be compared with those of later tests, performed at the age of about 18 months (or a bit earlier) to see whether milk can be re-introduced without risk.

ANAPHYLAXIS IS THE MOST SERIOUS FORM OF ALLERGY.
A FEW RECOMMENDATIONS…

"When a person with food allergy goes into anaphylactic shock, we must wait for the emergency ambulance team to administer Anapen, the self-injectable syringe of epinephrin".
Certainly not ! The earlier a patient receives epinephrin, the more effective it is! It is useful to know that the earlier the onset of anaphylactic shock (within minutes of eating the allergen), the more severe the reaction will be. Injecting Anapen immediately can save lives.
Unfortunately, it is impossible to know if and when a serious accident will occur when only moderate reactions have been seen in the past. This is why the symptoms of immediate allergy to food must be controlled every year by an allergist (if possible by the same physician and with the same laboratory test techniques). If, despite a well-conducted avoidance diet, a new allergic reaction occurs, the allergist must be informed. He/she will then decide whether the patient should be seen again.
If a child with food allergy is also asthmatic, it is very important to implement daily treatment by inhaled drugs and to assess its efficacy. Warning! When children with food allergy have a viral infection or any other condition that upsets the body functions, they are at increased risk of acute asthma if they eat something unexpected. Unstable asthma in patients with food allergy must be controlled by adequate treatment.

Food allergic children at school :
If the child requires individual attention at school, documentation (the care management project) must contain specific details, not only about health care measures in the event of onset of symptoms, but also the type of school meals they can eat! For example: "the child should not eat tree nuts" is far too vague. It is essential to notify: 1) eating at the school canteen is not allowed (this is very rare), 2) eating food prepared by the parents in the school canteen is allowed (more frequent), 3) eating commercial preparations of hypoallergenic food in the school canteen is allowed (this is often expensive), 4) normal canteen meals are allowed but certain foods are restricted (i.e.: kiwi). This last option can be applied to adolescents on eviction diets who have had no reactions since childhood and who are mature enough to differentiate foods for themselves.

From a mother : "I have an emergency kit which I know how to use and if Jules has an allergic reaction I do not need to bother the doctor."
OK, but... although the emergency procedures (administration of anti-histamines and corticosteroids, or sometimes even epinephrin) carried out by parents are vital, they may remain insufficient. You must call your doctor who will assess the potential seriousness of the reaction, or go to the Emergency Unit at your local hospital.

Allergist, CICBAA* Allergy staff, 2007
*Circle of Clinical and Biological Investigations in Food Allergy


Safety of prick-tests using food allergens - sept 2006
Prick-tests to foods are usually carried out as the first step in the diagnosis of food allergy. Severe anaphylaxis accounts for 4.9 % of allergies in children and occurs more frequently in adults, raising the possibility of systemic reactions to prick-tests in highly sensitized people. Several studies published in the literature have used commercial extracts. As for airborne allergens, concentrations causing a skin reaction of 15 mm do not present a risk of systemic reactions. Prick-tests to native foods--prick-in-prick tests--have been less extensively studied. The CICBAA1 data, from 1,138 food allergic patients of all ages, cover 34,905 prick-in-prick tests to foods. The wheal of these prick-tests has been regulary registered. The risk of systemic reactions can be evaluated at 0.008 %. There were no severe reactions and anti-histamine and corticosteroid therapy were sufficient. These results are similar to those of the large study in 2000 carried out by Devenney in neonates (0.005%). A review of the literature reveals only a few severe reactions in adults. The authors draw attention to the necessary precautions: temporary contra-indication for skin prick-tests in children and adults with grade 3 or 4 asthma, with particular attention to such foods as all kinds of nuts, fish, etc.

Codreanu F, Moneret-Vautrin DA, Morisset M, Guenard L, Rance F, Kanny G, Lemerdy P. The risk of systemic reactions to skin prick-tests using food allergens: CICBAA data and literature review. Allerg Immunol 2006;38:52-4


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