Natural history studies with the following design features provide a firm epidemiologic foundation for risk factor assessments and etiologic hypotheses:
(1) long-term cohort studies of a prospective design minimize biases resulting from poor parental recall;
(2) multiple evaluations over time provide important checkpoints during the dynamic period of childhood growth and development; and
(3) the inclusion of objective disease measurements strengthens these studies by validating subjective disease assessments (i.e. questionnaire data). (more…)

The protective effect of breast-feeding on asthma and allergy has been debated for more than 60 years without any hope of a consensus. A major problem is the lack of randomized controlled trials. However, breast-feeding has a number of other benefits and should be recommended irrespective of any effect on asthma or allergy. This is why randomized trials are not considered ethical. Thus, we have to rely on observational studies, which have produced conflicting results. Mothers who do or do not breastfeed differ in several environmental exposures, including socio-economic class, smoking and area of living, which influence indoor and outdoor exposure to pollutants. Despite statistical adjustment for these confounding factors, the evidence is never as robust as it would be with an randomized controlled trial. (more…)

By definition, allergy is a condition where a person has hypersensitivity to an environmental, drug, or food antigen (allergen) caused by an altered or unusual immune system reaction to the antigen.

Allergenic foods can impact the lungs when an allergic reaction individual inhales food particles that may have been released when the food was cooked or that were dispersed in aerosol form. Allergy to the allergens in cooked food has been reported by highly allergic patients who were exposed to their allergenic foods (say, fish, shellfish, or eggs) in an enclosed area (for example, a restaurant dining room) or during meal preparation. Most cases of asthma triggered by aerosolized food allergens involve adults engaged in specific occupations that regularly expose them to the allergens. In contrast, most cases of asthma in children are triggered when the allergen is eaten, not inhaled.

Many experts believe that if a baby can be protected from becoming sensitized to the most highly allergenic foods when their healthy immune system and the digestive tract are in the most vulnerable stage for allergy to develop, the incidence of lifelong food allergy and potentially life-threatening anaphylactic reactions to foods will be reduced and hopefully entirely prevented. When a baby has been identified to be at risk for developing allergy, measures to reduce allergic sensitization might be implemented at birth and the problems associated with future food allergy may be significantly reduced. However, as we shall see in later discussions, experts disagree on the best way to avoid this early allergic sensitization.

The reaction of asthmatics to these chemical compounds is not an allergy, but is more correctly described as allergy intolerance because the initial response is not a triggering of the immune system. The process involves an increase in the level of the inflammatory mediators that are responsible for the bronchospasm of asthma. These mediators include histamine and leukotrienes. They are released during the reaction to an allergen, and cause the muscular contractions that result in the difficulty in breathing and wheezing that are typical of asthma. By inhibiting (or turning off) other types of mediators, the chemicals in the food additives cause an increase in the level of antihistamine and leukotrienes. This results in increased bronchospasm, and a definite worsening of the asthma symptoms.

Oral allergy syndrome is an allergic reaction to food that is confined to the oral cavity (i.e., to the lips, and around the lips, roof of the mouth, tongue, hard and soft palate, and uvula) and adjacent structures. It differs from other food allergy in that its symptoms do not appear in any other location in the body, and always accompany respiratory allergy to inhaled allergens of plants, particularly plant pollens. Of course, symptoms in the mouth, throat, and upper respiratory tract can be part of a generalized reaction to foods, but in this case they are more accurately described as oral allergy symptoms. The term oral allergy syndrome applies specifically to pollen allergy (pollinosis) accompanied by reactions to certain raw foods when they are in direct contact with oral tissues. Individuals with Oral allergy syndrome typically have hay fever symptoms caused by allergies to trees, grasses, and weeds. They experience irritation in the mouth (lips, tongue, roof of the mouth) and sometimes the throat after eating specific types of raw fruits, vegetables, and sometimes nuts.

The two strongest risk factors for asthma in childhood are a family history and immediate hypersensitivity to common allergens. This immune response includes both IgE antibodies and helper T cells type 2 (Th2), both of which are thought to contribute to the inflammation in the respiratory tract. Children with asthma who mount an immune response to inhalant allergens have an increased risk of developing asthma because of this combination of genetics and exposure. However, it is sensitization to indoor allergens (e.g. dust mites, cats, dogs, and cockroaches) that is strongly associated with asthma. (more…)

The prevalence of asthma increases with increasing levels of Dichlorodiphenyldichloroethylene (DDE). However, the effect of early-life exposure, the fundamental window of exposure, is unknown. The investigators assessed the association of prenatal exposure to DDE and other organochlorine compounds with atopy and asthma during infancy. All women presenting for antenatal care in Menorca (Spain) over 12 months starting in mid-1997 were invited to take part in a longitudinal study; 482 children were subsequently enrolled and 468 (97.1%) provided complete outcome data up to the 4th year of the study. (more…)

It is clear from the results of large epidemiologic studies that while atopy is a major risk factor for asthma, it is usually not sufficient by itself to drive the disease process to chronicity, as less than 25% of atopics develop persistent asthma. The situation in childhood is further complicated by an additional series of development factors, related to postnatal maturation of respiratory function. (more…)

If you suspect that certain foods trigger wheezing or asthma symptoms in your child, your first action should be a consultation with your pediatrician to determine the exact inventory of foods your child is allergies to. The doctor will probably refer you to a pediatric allergist, or may carry out the tests him-or herself to identify your child’s reactive foods. (more…)

Up to 85% of asthmatics patients have symptoms of wheezing during or after exercise. Moreover, many patients diagnosed with allergies or asthma have family allergy history and bronchospasm. Bronchospasm or a bronchial spasm is a sudden constriction of the muscles in the walls of the bronchioles. Bronchospasm is one of the condition or tightness of the airways caused by exercise. (more…)

Many children are living with asthma. Asthma is a lung disease because the constriction of small airways (bronchioles). When this happens, there is moderate to severe difficulty in breathing came with by wheezing. Even though wheezing is not always heard but most of the time it is always present. (more…)

Many people will tell you that they have a food allergy; in fact in today’s society it is considered to be trendy, with celebrities announcing their food allergies on the front covers of magazines. However, true food allergies aren’t as common as you might think and they usually only affect as few as two percent of children. (more…)