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The origin of the rumor
Many parents, and even health professionals, believe that eczema in a child is a manifestation of a food allergy. According to what wrote in 2010 the American dermatologist Ki-Young Suh, allergists and dermatologists have different opinions on the subject. The former claim that certain foods can cause eczema flare-ups. The latter claim that eczema caused by food allergy is rare.
In a study which has just been published, a group of American dermatologists concludes that the foods most often suspected of causing eczema are eggs, milk, peanuts and soy.
What is the link between eczema and food allergies?
According to these latest researchers, about one in three children who suffer from moderate to severe eczema will develop food allergies. This is more than in children in general, where this proportion is only 4 to 10%. In other words, food allergies are more common in children with eczema.
Studies also indicate that babies who develop eczema before the age of three months are more at risk of being allergic to foods at the age of one year, according to Ki-Young Suh. In addition, children in whom antibodies against certain food allergens are detected are more likely to develop eczema early in life and it is likely to be more severe.
However, these observations do not mean that it is food allergies that cause eczema. In fact, it could even be the reverse mechanism, depending on the study of 2022, focusing on hypersensitivity to food allergens in those with atopic eczema (atopic means inherited predisposition). When a child suffers from eczema, the skin no longer plays its barrier role as well, explain the four researchers. Food allergens can thus enter the body and be captured by cells of the immune system in the epidermis, the Langerhans cells. They are then transported to the lymph nodes to be presented to another type of immune cell, T cells. This is what would cause sensitization of the child, who would then develop an allergy.
In other words, it is after skin contact with a food substance that the child suffering from eczema would become allergic to it.
We must not forget that several factors can trigger outbreaks of eczema: respiratory allergens, bacteria present on the surface of the skin, irritating substances, changes in climate and psychological stress. In addition, explaining to parents how to take good care of their child’s skin is usually enough to improve its condition. It is in this context that the dermatologist Ki Young Suh wrote that only a very small percentage of children have eczema due to a food allergy.
Rather vague symptoms
What can increase the confusion for parents is that some allergy symptoms are non-specific and can have different causes. This is especially true for cow’s milk allergy. Of the British researchers have also concluded that the symptoms of cow’s milk allergy described in some guidelinesincluding eczema flare-ups, are common in babies, leading to overdiagnosis of milk allergies.
Confusion can also be significant with skin symptoms, which can be quite varied. For example, the clinical manifestations of cow’s milk allergy can occur as soon as 30 minutes after the child has been exposed to it, wrote in 2010 Italian researchers. When it does, it is usually hives or erythema, two conditions distinct from eczema. In fact, if a food causes eczema, it will develop later, that is to say several hours or even days after exposure.
According to the Italian researchers, there would be four times more parents who say that their child is allergic to a food than children who really are. They therefore insist that an oral challenge test is the best way to confirm that a child is allergic to a food. During this test, a food to which the child is suspected of being allergic is given by mouth, starting with small amounts and gradually increasing them during the examination.
The risks of avoiding certain foods
According Ki Young Suhalthough the effectiveness of the strategy of simply eliminating foods to treat eczema has not been demonstrated, 75% of parents say they have used it.
Without supervision, these diets carry risks. According to experts, elimination diets (where a food is completely avoided) that are not necessary can worsen allergic reactions and affect the quality of life of children and their families. For example, in 2015, italian doctors reported the case of a baby fed exclusively with a rice drink because of his eczema and who had developed kwashiorkor, a form of malnutrition characterized by protein deficiency.
Although there seems to be an association between the presence of eczema and the appearance of certain food allergies, the latter are rarely the cause of this disease. In fact, it could even be the opposite. Moreover, eliminating foods from a child’s diet is not without risk. This strategy should be used only when the food allergy has been convincingly confirmed and under professional supervision.
Photo: Cera Ve
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