Allergies in Children

imageAllergies in children are extremely common. The statistics are staggering and the incidence of childhood allergies and childhood asthma is increasing dramatically. It is estimated that over 8 million children in the U.S. have allergic rhinitis, or hay fever, and over 5 million have childhood asthma. Recent studies have also shown a dramatic increase in food allergies in children and it is now estimated that over 8% of children are allergic to one or more foods. Over 10% will have eczema or atopic dermatitis during early childhood. In a general pediatrician’s office, it has been estimated that over 20% of children seen by pediatricians on a daily basis are because of childhood allergy symptoms or childhood asthma symptoms. Most children with allergies can be managed by the pediatrician, but many require a referral to a pediatric allergist because of recurrent, chronic, or severe allergy symptoms.

What is an allergy?

In its simplest terms, an allergy is the result of the immune system recognizing a normally harmless substance (such as a food or pollen) as a potential harmful substance. As critical, necessary, and helpful the immune system is to good health, an allergy is an example one arm of the immune system misinterpreting vital information presented to it, and reacting to that information inappropriately. The allergic state is also referred to as atopy.

How do childhood allergies start?

Regardless of age, all allergies start the same way. Allergic individuals are born with an allergic gene as part of their DNA. This gene may express itself very early in life, or it may lay dormant for many years before activation. Once activated, the potential for allergies will always exist.

The process of becoming allergic involves a series of very complicated and intricate relationships between many chemicals, called mediators or cytokines, and cells in the immune system. Once the allergic gene is “turned on”, the allergy activation process begins when one is exposed to an allergen such as peanuts, dust mites, or pollen for the first time. This exposure may have occurred in utero, or through exposure on the skin, by inhalation, or ingestion. The specific allergen is then recognized by specialized immune cells and then processed by the immune system. As a result of this initial exposure, allergy antibodies are formed to that particular allergen. Once formed, these antibodies are present in the tissues and the circulation, and are now primed and activated to react during a subsequent exposure to the allergen. Upon exposure of the antigen to the preformed antibodies, the two molecules attach like a key in a lock. This attachment is the critical step which then sets off a cascade of cellular events, leading to the release of histamine and other chemical mediators. These chemicals, once released, cause dilation the blood vessels, constriction of smooth muscles, and the activation of mucous glands. The grand finale of this process is an allergic reaction, which can vary in its intensity from mild to severe.

How do childhood allergies present?

Childhood allergies can become evident at any age. Contrary to popular opinion, newborn allergies do exist, as do allergies in babies of all ages. As a general rule, if a newborn, infant, or toddler presents with childhood allergy symptoms, the most likely allergen responsible is one that they are exposed to repeatedly, and in this age group, the most likely allergen is a food. And, the earlier the presentation, the more likely the baby is allergic to milk. It is important to note that milk allergy can occur in nursing babies as cow milk protein ingested by the mother can be passed to the baby through the breast milk. Newborns and infants allergic to cow’s milk based formulas or cow’s milk products ingested by the mother may first manifest their allergy symptoms with gastrointestinal symptoms such as excessive spitting and even projectile vomiting after feeding. These newborns and infants are also commonly irritable and have colic as a result of abdominal discomfort. If the newborn or infant being fed a cow’s milk formula is exhibiting these symptoms, it is often necessary to try a milk free formula, such as a soy containing formula. Soy allergy or intolerance is also seen, but much less frequently that cow’s milk allergy. If the symptoms do not improve, then it is prudent to try a hydrolyzed milk formula. A hydrolyzed formula is one in which the milk protein is degraded and broken down into its amino acid components, a process which eliminates the allergy potential of the offending intact protein. For the breast fed infant having symptoms, it would necessary for the mother to eliminate milk from her diet to ascertain if the milk is causing the symptoms.

Another common infant allergy symptom is eczema. Eczema generally presents in the first few months of life as red, dry, itchy patches on the skin. It is commonly found on the cheeks and behind the ears, but as the child grows, it is most characteristically found in the bends of the arms and in the folds behind the knees. In addition to isolated eczematous patches, children with eczema commonly have generalized dry skin. In approximately half of the cases of eczema in childhood, allergies are the cause or exacerbating factors. When allergies are the cause of eczema, it is commonly referred to as atopic dermatitis, although both of these terms are used interchangeably. In the allergic variety, an allergy to a food is often responsible, although exposure of allergens to the skin, such as proteins of dust mites, can also exacerbate atopic dermatitis. High on the list of suspected foods in the child with eczema are milk, eggs, and wheat. As a general rule, eczema tends to improve over time, and most children are symptom free by the age of six. Unfortunately, some children who have atopic dermatitis go on to develop nasal allergies and/or childhood asthma, a progression described as the “atopic march”.

Children are commonly allergic to the things they breathe. As a general rule, the more frequent and chronic the exposure, the earlier the onset of allergy symptoms. For example, a child who has repeated or chronic exposure to pets, dust mites, or cockroach allergen may begin to exhibit respiratory symptoms beginning as early as a year of age because of the constancy of the exposure. On the other hand, because of episodic exposure, a child is unlikely to develop allergies to seasonal pollen until three or four years of age.

The most common manifestation of allergies in children is allergic rhinitis. Allergic rhinitis results from the inhalation of allergens into the nose and the subsequent allergic inflammation which results in the lining of the nose and sinuses. The inflammation leads to swelling of the tissues in the nose called turbinates and the over production of mucous from the activated mucous glands. The result is nasal congestion, runny nose, sneezing, and itching. It is common for the eyes to be affected as well, a condition called allergic conjunctivitis. This condition leads to tearing, redness of the eyes and intense eye itching. When both the nose and eyes are affected by allergens simultaneously, the diagnosis of allergic rhino-conjunctivitis is applied.

Allergy symptoms in children can be episodic or chronic. Pollen exposure in pollen allergic children will result in symptoms only during the relevant pollen season. These seasonal flare-ups are called hay fever by both the lay public and medical personnel, even though hay is usually not the cause, and fever is generally not present. Episodic symptoms may also result on the occasion exposure to a cat or dog. On the other hand, chronic and daily symptoms will likely result from exposure to dust mites, mold spores, and in homes where pets reside. In urban inner-city environments, allergy to cockroaches is a major cause of persistent allergy symptoms in children. Some children have both year-round, or perrineal symptoms, and seasonal allergy symptoms concomitantly. Such a child may have daily nasal congestion and runny nose, only to get acutely worse in during the spring and fall when tree, grass, and weed pollens are present in the air.

Just like the nose and eyes can be a target for allergies, so can the lungs, and more specifically the bronchial tubes.  In approximately 50% of all children with asthma, the asthma is caused and exacerbated by allergies. Childhood asthma can present initially at any age, but it is often not diagnosed until after age three. Because the diagnosis of childhood asthma can be difficult to make, children presenting with symptoms compatible with childhood asthma are often given the diagnosis of reactive airways disease, or RAD. Pediatricians are reluctant to diagnose a child with asthma, but the sooner the diagnosis can be made and confirmed, the quicker one can begin appropriate childhood asthma treatment. It is very important to distinguish between allergic asthma and non-allergic asthma in children, as the treatment can vary depending on the presence or absence of allergies.

Childhood asthma can mimic other common pediatric respiratory illnesses, sometimes resulting in the delay of treatment. The most common presenting symptom of childhood allergic asthma is coughing. It may present as a recurrent or chronic nighttime or early morning cough and sometimes it is the only childhood asthma symptom. As the symptoms worsen, wheezing and difficulty breathing may be present. Symptoms tend to be made worse with exercise and upon exposure to increasing amounts of allergens and non-allergic irritants such as cigarette smoke.

Diagnosis of childhood allergies

Allergy testing is generally necessary to identify the allergen(s) responsible for childhood allergies. Contrary to popular belief, allergy testing can be performed at any age. Of the two reliable allergy testing methods available, skin testing is the testing method preferred by most pediatric allergists. This is because it can take less than one minute to test to 40 or more allergens, and the results are evident in just 15-20 minutes after the tests are applied to the skin. Prick skin testing is well tolerated by even very young children as its application is quick and only minimally uncomfortable. With the advent of a device called a multi-test, multiple allergens can be applied to the skin simultaneously, shortening the testing procedure while allowing multiple allergens to be tested. These tests are generally applied to the back of the child or the forearms. Once applied, the allergens are left on the skin for 15-20 minutes. During this time, positive reactions can cause local itching. After this short duration, the allergist or nurse can ascertain which inhalants or foods the child is allergic to and the severity of the allergy.  Many foods can be testing by the skin prick method. In addition, inhalant allergens such as dust mites, pets, mold spores, cockroach, weed pollen, tree pollens, grass pollens, and others can be tested. It is important that children being allergy skin tested be off of all antihistamine for 3-5 days prior to testing.

Allergies can also be tested through the blood. These tests, called RAST or ImmunoCap, are used by allergists under certain circumstances. Since antihistamines do not interfere with the results of these tests, it might be used if the child is presently on an antihistamine or has been taking antihistamines within the prior 3-5 days. Also, if the child has eczema, or some other skin condition which would interfere with skin testing, then the blood test may be ordered.

No allergy test is perfect. Both skin testing and blood testing can be associated with false positive and false negative results. It is for this reason that an allergist will attempt to correlate the child’s allergy symptoms with the allergy test results in order to establish a cause and effect relationship.

Treatment of childhood allergies

The treatment of childhood allergies is no different than the treatment of allergies in an adult. Regardless of age and the cause of the allergies, the cornerstone of treatment is environmental control. Simply put, one needs to minimize exposure to known allergens to the greatest degree possible. In theory, this treatment approach is simple, but in reality it is very challenging, For instance, if a child is allergic to the family cat, the best treatment option is that the cat should be removed from the house. However, the compliance rate for this recommendation is very low due to the fact that pets are loved and they have become members of the family in many homes. Many parents also express concern over the pycho-social impact on the child that may result by the removal of the cat or dog.

Environmental control is also difficult when one is told to eliminate an allergen that cannot be seen. A case in point is house dust mites and mold spores. Fortunately, there are very effective and inexpensive allergy control products that can be very helpful in decreasing an allergic child’s exposure to these allergens. But, regardless of the challenges of environmental control, every effort must be made to maintain the allergic child in an as allergy free an environment as possible.

As important and effective as environmental control can be, there are allergens which are so ubiquitous in our environment that effective allergen reduction procedures are only minimally effective. This is especially true for pollens which the allergic child is exposed to most of the year when outdoors. These allergenic pollen grains are very light and are carried hundreds of miles by a light breeze. On a practical note, if a child is allergic to oak tree pollen and Bermuda grass pollen and in the family yard is a big beautiful oak tree and a carpet of Bermuda grass, it is not necessary to uproot the oak tree and replace the Bermuda grass. Even in the absence of the tree and grass, they will be exposed to high oak tree and Bermuda grass pollen that comes from the yards of neighbors near and far.

The second treatment option is the use of allergy medications. Allergy medications are not curative; they are used to reduce the child’s symptoms while other more critical components of the treatment plan are implemented. The most commonly recommended and prescribed allergy medication for children are antihistamines. Antihistamines have been used for many decades and they have an excellent safety profile. Historically, the main disadvantages of antihistamines were their sedative affects and the frequency which they had to be taken. Non-sedative antihistamines are now available, as well as antihistamines which can be taken once or twice a day. Antihistamines are effective in reducing the symptoms of runny nose, post nasal drip, sneezing, and nose or eye itching, but they do very little for nasal congestion. They are only minimally effective for coughing.

They other classification of medications which can be very helpful in childhood allergies are corticosteroids. Oral or injectable corticosteroids can be extremely helpful in eliminating or reducing the symptoms of allergies, but they should be prescribed judiciously in cases of difficult to control or severe allergies. Even though steroids are safe in children when taken for short periods of time, long term use should be avoided due to potential side effects. One should discuss the benefits and risks of these medications with one’s allergist or pediatrician, if they are recommended.

Topical steroids, on the other hand, are extremely safe in children, even if taken for long periods of time. These topical steroids are available as nose sprays, inhalers, eye drops, and creams and ointments for the skin. There have been some research studies which have suggested that long term use of topical steroids could slow down a child’s rate of growth, but other studies failed to establish this suggested relationship. Most allergy specialists are confident of their safety and they use these medications quite successfully in allergic children.

There are many other allergy medications available and many undergoing clinical trials. Your pediatrician or allergist will decide which medication are most appropriate, but the goal to is to keep children on as little medicine as necessary to stay well.

Even though no one should claim that there is a “cure” for allergies, the next best thing to a cure is the potential to increase a child’s tolerance to the allergen(s) to the point that they are symptom free, or at least, greatly improved. This can be accomplished through a desensitization process called immunotherapy. Immunotherapy is the only form of allergy treatment that gets to the cause of the problem, and represents a significant advantage to other “band-aid” approaches to childhood allergy treatment. This desensitization process is accomplished by exposing the child’s immune system to increasing amounts of the allergen over a long period of time. As the exposure increases, the child will likely become more and more tolerant to the allergen(s). The goal is to increase the child’s tolerance to the things that the child is allergic to so that when the child is exposed to normal amounts of the allergen(s), for example dust mites or pollen, they will not have symptoms. This form of treatment is estimated to be 80-85% effective in significantly reducing or eliminating the child’s allergy symptoms.

Immunotherapy, or desensitization, should always be thought of as a long term approach to health, and not as a quick fix. Allergy relief from immunotherapy does not happen quickly and it commonly takes 6-12 months to begin to see improvement in symptoms. If improvement is seen, then the process should be continued for 3-5 years in order to maintain long term, if not lifelong, improvement.

Immunotherapy has been administered to children for many decades. The gold standard for immunotherapy in the United States has been allergy injections or allergy shots. In Europe, however, immunotherapy has historically been given as drops under the tongue, commonly known as sublingual immunotherapy, or SLIT. American allergists have been slow to embrace the SLIT approach, but its acceptance is becoming more commonplace, especially in light of the very favorable clinical trials which have demonstrated SLIT’s effectiveness and safety. Both allergy shots and SLIT have their distinct advantages and disadvantages. One should consult their allergist concerning which desensitization process is best for their child.

For children with recurrent or chronic allergy symptoms, severe symptoms, or symptoms which do not respond to conventional therapy, consultation with a pediatric allergist should be sought. A pediatric allergist is trained to recognize the symptoms of childhood allergies, test for their causes, and to recommend the best therapy and treatment available toward the goal of totally eliminating or greatly reducing the symptoms of childhood allergies.

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