Childhood

The incidence of allergies in children has increased significantly in the last two decades. On its heels has come a rise in asthma, which is now the number-one diagnosis for child hospital admissions. There are more children with asthma, hay fever, and eczema (allergic rash) than ever before. In my own practice in recent years, I have seen a steady stream of children, as young as six months old with these conditions. Parents tell me their children have runny noses, itchy and watery eyes, coughing and wheezing, without any evidence of viral infection. Many are convinced that their child's exposure to flowers, grass, weeds and pets is the culprit.

General Information on Allergies
Allergy is the term used to describe the immune system's sensitivity to an allergen - any normally benign substance in the environment, such as pollen or mold, that can trigger an allergic reaction in a susceptible person.. The immune system can become sensitized (prone to allergic reaction) after a person inhales an airborne allergen like pollen, or eats certain foods, like milk, peanuts, or eggs. Allergies can develop in the first few months of life, evident as nasal congestion, arching, rash, or diarrhea following the ingestion of certain foods. Refusing food and/or vomiting are good signals of a food allergy in infants. Allergies affect all races and have been found in all parts of the world.

When a person is sensitized to an allergen, any time he or she is exposed to it, the immune system triggers a release of chemicals, such as histamine, that cause the well-known allergy symptoms listed below:

• sneezing
• itchy or stuffy nose
• watery nasal discharge
• itchy eyes
• eye tearing and redness

And less frequently:

• cough
• palatal (roof of the mouth) itch
• bronchial asthma symptoms, such as wheezing
• eczema
• urticaria (hives)
• anaphylaxis

Genetic Factors
If your child develops allergies, the cause will have been a combination of the genes he or she inherited from you, as well as their environmental exposures. As parents, if one of you has a history of allergies, then each of your children will have about a 40 percent chance of developing allergies. If both of you have allergies, then the risk increases to about 80 percent.

Genetic factors have been intensively researched in recent years, and what seems clear is that the genetics of allergy are quite complex, involving interactions between our environment and inherited tendencies. The exact genes that contribute to allergies have not been fully identified.

Environmental Exposure
In contrast to genetic influences, the role of environmental exposure has been well-established. The presence of pets, such as cats and dogs, in the home clearly affects whether your child will be reactive to animal dander, a common allergen. It is also true, however, that children can still become sensitized to allergens that have been eliminated from the home. For example, when it comes to animal dander, children can be exposed when they go to school or daycare, as the allergens may be on the clothes of classmates who have pets.

There are also many other theories as to possible causes of allergies in children (and adults):

• Exposure to particulate matter released from the burning of diesel fuel, mainly from trucks, triggers the allergic response. This theory has been supported in lab experiments where certain cells exposed to diesel particulate matter show signs of an allergic response.
• Air pollution has been cited as a stimulus that can provoke the development of childhood asthma. Evidence for this is that high ozone and sulfur dioxide levels often coincide with peak asthma exacerbations or flare-ups.
• Tiny airborne mold spores (specifically, the species Alternaria), which cannot be seen, have recently been associated with epidemics of asthma in certain cities in children and adults.
• Dust mites and cockroaches appear to be major sensitization agents in our inner cities. Cockroaches have proven very difficult to eliminate; dust mites are only somewhat easier.

Food Exposure
The abundance of potential contributors to allergy may seem daunting, but studies have shown that certain measures, like breastfeeding for at least six months may delay or prevent the development of allergies. Breast milk will not generate an allergic reaction and can also boost an infant's immune system. If formulas are necessary, then hypo-allergenic or protein hydrolysate formulas are preferable to soy. Soy products are a common allergy trigger for children, and those who are given a soy formula instead of breast milk are more susceptible to an adverse reaction. Also, a late introduction of solid foods (after six months of age) is recommended.

What Is a Parent to Do?
The goal shared by both physicians and parents in treating childhood asthma and allergies should be to minimize the side effects of medications while maximizing the chance of children leading normal daily lives. Clearly identifying allergens that your children are sensitive to through allergy skin testing or using a specific blood test (called a RAST test), can be extremely helpful in implementing the following avoidance and control measures.

Avoidance and Control Measures for Children with Allergies

• Removing carpet, encasing bedding with breathable covers, hot laundering of linens, and keeping windows closed at night and in the early morning hours can minimize your children's allergen exposure. Also, decreasing dust mites in the bedrooms of allergy- and asthma-prone children can lead to a major improvement in their lung function and reduce the need for concomitant medications to treat their flare-ups.
• Avoidance of allergy triggers, which may include such irritants as tobacco smoke and perfumes and colognes, will also help your allergic children. Smoking while pregnant has been linked to an increased risk of wheezing in infants.
• Unfortunately, since viruses, particularly rhinoviruses (a cause of the common cold), are the most common stimulant of childhood asthma, and there are as yet no specific practical means to inactivate this virus or decrease its penetration in the upper respiratory tract. We are powerless to prevent virus exposure. However, vaccination with flu vaccine and appropriate new agents, as they are released and shown to be safe for children, will be very worthwhile.

Weather and seasonal changes can aggravate asthmatic symptoms. Unfortunately, these factors, like pollen or mold spores, are difficult to avoid. Still, scheduling outdoor playtime or exercise at non-peak pollen periods, such as afternoons or early evening, can be effective.

• Having your child wear a mask when helping with gardening, vacuuming, or dusting can be very helpful.
• Delaying the introduction of certain foods can help prevent food allergies. According to the American Academy of Allergy, Asthma, and Immunology (AAAAI) these are good timelines for introducing new food to your child:
  • Six to 12 months: vegetables, rice, meat, and fruit
  • Twelve months: milk, wheat, corn, citrus, and soy
  • Twenty four months: eggs
  • Three-years: fish and peanuts

Medications
In addition, the recent availability of newer therapeutic agents for children has been extremely useful in managing rhinitis as well as asthma:

• Non-sedating antihistamines available in liquid form and rapidly dissolving tablet form can be very beneficial.
• Sodium cromolyn, an over-the-counter nasal spray, can help prevent nasal allergy symptoms.
• Inhaled nasal corticosteroids have been also shown to be quite effective in ameliorating allergic inflammation.
• A leukotriene antagonist, a new class of drugs, has been approved for the treatment of childhood asthma and is available in a chewable form. Such agents can decrease asthma symptoms and also improve the quality of life.

In summary, allergies are due to genetic tendencies and reactions to normally harmless substances in the environment (allergens). Common allergens include pollen grains, dust mites, airborne mold particles, and animal dander. Long-term complications of allergies in children include sinus problems (sinusitis) and recurrent ear problems such as a buildup of fluid in the middle ear (otitis media). These conditions may require antibiotics and, in the care of ear problems, the placement of ear tubes for ventilation.

It is my opinion that the biggest challenge we face together as physicians and parents is the lack of participation of the allergy specialist in the care of our allergic and asthmatic children. Children who suffer from allergies and/or asthma have impaired performances in school, as well as difficulties at home. There were 14.7 missed days of school and over 700,000 emergency room visits due to asthma among children younger than 18. Primary care providers, such as family physicians and pediatricians, need to be encouraged to involve an allergist early on and more frequently in the care of their patients. It is important to trust the allergist as an equal partner in the delivery of appropriate health care. Meeting this challenge will be extremely important to both children and their parents.