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Childhood Allergies

What is a childhood allergy?

Allergy is one of a group of medical problems scientists call atopic diseases that tend to recur over and over again in families. A family history of allergies is the single most important factor that predisposes a person to develop allergic disease. If one parent has allergic disease, the estimated risk of the child to develop allergies is nearly 50%. The child’s risk grows to 70% if both parents have allergies.  

The following diagram represents the three atopic diseases: allergies, asthma, and eczema, and their strong but not exclusive correlation with one another. This means that the genes that cause each of these medical problems are closely linked and tend to be inherited together. However, the fact that a person has these genes does not indicate that the disease will show itself in the lifetime of an individual. For example, a child who develops eczema early in life is much more likely to have asthma, food allergies and allergic rhinosinusitis. The parents, grandparents and siblings are also more likely to have one or all of these problems at some point in their lives. Concepts such as these help scientists develop strategies to prevent the development of these conditions over a lifetime.  

The earlier allergies show themselves in childhood, the worse they will tend to be. The earliest expression of allergy in childhood is a food allergy. This allergy typically takes the form of eczema but can also cause rhinitis, sinusitis, otitis media (recurrent ear infections), and childhood asthma. Most food allergies that do not cause severe life threatening allergic reactions resolve by school age or puberty. This is particularly true for milk allergy which is very common in early childhood. Others such as peanuts, tree nuts, fish, and shellfish tend to last a lifetime.

Allergies to environmental allergens such as pollens, dust mites, molds and animal danders do not appear until two or three years of age, at the earliest. However, once they do appear they tend to gradually worsen and become more and more complicated. For example, a child with grass or dust mite allergy at three to five years of age will typically have multiple allergies by puberty and eventually suffer from complications of the allergies over time.

How is a childhood allergy diagnosed?

For children under the age of five, allergies are typically diagnosed using a blood test. Skin testing (prick only) can be used, but minimally, since false negative (NOT false positive) results occur. After the age of five, the skin test is the most accurate method for diagnosing most allergies.

How is a childhood allergy treated?

Vigorous treatment of childhood allergies is important not only to help the allergic child grow and develop normally; it can also prevent the development of lifelong allergic complications such as asthma and severe chronic sinus disease. To accomplish this effectively, it is important to intervene with effective allergy treatment as early as possible. For example, scientifically controlled studies have shown that the use of immunotherapy in children can prevent the development of chronic asthma but only if used before asthma has become moderate or severe. Unfortunately, many people do not seek the help of a Board Certified Pediatric Allergy and Immunology specialist until the asthma has already progressed to a severe form. Then it may be too late.

How can childhood allergies be avoided?

Childhood allergies can be avoided in the same ways as adult allergies. Refer to the adult asthma section of this site for more information.

How can childhood allergies be prevented?

As we’ve noted, allergies tend to run in families. In other words, children in families where one or both parents have allergies and related conditions (e.g. eczema, asthma) are more likely to develop allergies. That is why many prevention efforts have been targeted to children of allergic parents. We cannot change the genes we inherit from our parents. However, it has been known for some time that how our genes express themselves can be influenced by our environment.

Food

Food allergies in children can cause a variety of problems that range from eczema to life-threatening allergic reactions. The major strategy for preventing food allergies is to delay exposure to potentially allergenic foods and liquids, since newborn infants may be more likely to become allergic to foods than older infants. Mothers should exclusively breast feed their infants for at least four to six months, if possible, since breast milk is much less likely to produce an allergic reaction than formula and can strengthen the child’s immune system. Any supplements should be limited to either water or pumped breast milk, if possible. Infants that are not breast fed or are fed with breast milk and in need of a supplement, should be fed partially pre-digested, protein hydrolysate formulas such as Alimentum or Nutramigen rather than milk or soy-based formulas.

Infants should not be fed solid foods until they are six months old. When infants are six to 12 months old, vegetables, rice, meat, and fruit can be introduced to their diets. Each food should be introduced individually (one at a time for several days before another is introduced) so parents or caregivers can identify and eliminate any foods that cause a reaction. After the child is one year old, milk, wheat, corn, citrus and soy may be added. At two years of age, the child may have egg. Finally, at age three, fish and peanuts may be introduced.

Environmental

It makes good common sense that since some airborne substances may trigger allergy symptoms, including eczema, rhinitis and asthma, that reducing contact with these substances early in life may delay or prevent the onset of allergy conditions. The evidence for this relationship is clearest in the case of dust mites, which are found in large quantities inside the home. Taking steps to aggressively control dust mites in the homes of high-risk children may reduce the occurrence of dust mite allergy in these children.  

However, there is scientific evidence that avoidance of other allergens early in life is not particularly helpful and, in some circumstances, even harmful. Recently published data has made the relationship between early life exposure to animals and the eventual development of allergies and asthma much more confusing. For example, some evidence seems to show that early life exposure to animals may make children more likely to develop allergies and asthma whereas more recent evidence seems to show that early life exposure to animals (dogs and cats, in particular) may protect children from developing these diseases later in life. Your allergy and immunology specialist can address this issue with you to give you the most current information and can match this current information with the needs of your family. In general, it appears that living on a farm or having a dog seems to have a favorable influence on reducing allergy and asthma development in at-risk children.

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