The incidence of allergies in children has increased significantly in the last two decades.

There are more children with asthma, hay fever, and eczema now, than ever before. Closely following this increased prevalence of allergies is the rise in asthma, which has become the number one diagnosis for child hospital admissions. Parents usually tell the doctor that 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
Allergies can develop in the first few months of life, evident as nasal congestion, cough, rash, or diarrhea following the ingestion of certain foods. Allergies affect all races and have been found in all parts of the world. Allergy is the term used to describe our immunological sensitivity to an allergen (any substance that causes an allergic reaction). This sensitization may occur by inhaling airborne allergens or eating food that contains allergens.

The consequence of allergens entering into our body involves the release of chemical messengers that bring about the well–known symptoms of allergy listed below:

• Sneezing.
• Itchy or stuffy nose.
• Watery nasal discharge.
• Itchy eyes.
• Watery eyes and redness.

And less frequently

• Cough.
• Palatal (roof of the mouth) itch.
• Bronchial asthma symptoms, such as wheezing.

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 child will have about a 25% chance of developing them. If both of you have allergies, the risk increases to about 50%. Genetic factors have also been intensively researched in recent years and what has emerged is that the genetics of allergy are quite complex, involving interactions between our environment and inherited tendencies. The exact genes that account for our allergies have not been fully identified.

Environmental exposure
In contrast to the genetic influences, the influence of environmental exposure has been well–established. The presence of pets, such as cats and dogs in homes clearly determines whether your susceptible child will be reactive to these allergens. It is also true, however, that children can still become sensitized to allergens that have been eliminated from the home environment. Exposure to allergens, such as animal dander, is hard to avoid in school or day care and in outdoor areas, as these allergens may be on the coats and clothing of children from homes with pets. There are also currently many theories as to other possible causes for allergy 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 proved in the laboratory, 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 among children and adults.

Dust mites and cockroaches appear to be major sensitization agents in our inner cities. Cockroaches have proven to be very difficult to eliminate, dust mites are somewhat easier. This abundance of possible causes may seem daunting, but studies have nevertheless shown that certain measures like maintaining a pet–free home, breastfeeding, or soy formula feeding for at least six months or more, along with the late introduction of solid foods (greater than six months of age) can delay the onset of allergic symptoms in susceptible children.

Be an observant parent
The goal shared by both physicians and parents alike in treating childhood asthma and allergies should be to minimize the side–effects of medications while maximizing the chance of our children to lead 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 to you in implementing the following avoidance and control measures.