The geographical variation in the prevalence of asthma in children does not coincide with variations in air pollution levels. The increase in the prevalence of asthma and allergies seen over the last decades was paralleled by a decrease in emissions of SO2 and particles from coal combustion, and an increase of emissions from motor vehicle traffic. There is a growing number of studies suggesting that increased exposure to traffic exhausts, particularly diesel exhausts, may be a risk factor for the new onset of asthma. (more…)

The prevalence of atopic dermatitis is increasing in Western societies. The hygiene hypothesis proposes that this is due to reduced exposure to environmental allergens and infections during early life. The authors examined factors associated with a diagnosis of atopic dermatitis at 3.5 years of age, especially those factors implicated by the hygiene hypothesis. The Auckland Birthweight Collaborative study is a case–control study of risk factors for small-for-gestational-age babies. Cases were born at term with birth weight at or below the 10th centile; controls were appropriate for gestational age, with birth weight above the 10th centile. (more…)

Asthma is a complex syndrome rather than a single disease entity. Different phenotypes with varying prognosis and determinants have been described, particularly over childhood years 2 and will be discussed in detail in the following. For example, transient early wheezing is characterized by the occurrence of wheezing in infants up to the age of 2 to 3 years which disappears thereafter. The main predictor of these wheezing illnesses is premorbid reduced lung function before the manifestation of any wheeze. These decrements in pulmonary function are in part determined by passive smoke exposure in utero 4 and result in symptoms of airway obstruction when infants get infected with respiratory viruses. (more…)

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 effects of exposure to environmental tobacco smoke (ETS) on children have been extensively studied and numerous surveys have consistently reported an association between environmental tobacco smoke exposure and respiratory diseases or respiratory allergies. Strong evidence exists that passive smoking increases the risk of lower respiratory tract illnesses such as bronchitis, wheezy bronchitis and pneumonia in infants and young children. (more…)

An allergic patient’s history may point the clinician’s assessment to a specific area or organ system during allergy testing. In general, physical examination may be standard; shortage of findings isn’t going to rule out allergy.

Essential indicators are a starting point in any physical examination of allergic patients. Respiratory rate is essential as well, but hyperventilation is more a representation of minute ventilation (respiratory rate × tidal volume) than respiratory rate on it’s own. (more…)

Atopic Dermatitis is considered to be one of the first manifestations in the atopic march. The aim of this study was to investigate prospectively the natural course of Atopic Dermatitis to determine factors influencing its prognosis and to analyse the relationship of Atopic Dermatitis with childhood asthma. The Multicenter Allergy Study, a German birth cohort, followed 1314 children from birth to age 7 years. Physical examinations, parental interviews on atopic symptoms and diagnoses, and determination of specific immunoglobulin (Ig)E levels were performed regularly. (more…)

During recent decades there has been extensive epidemiological research to explore the increasing prevalence of asthma and allergy in childhood. The worldwide variations in the prevalence of these diseases necessitate regional rapport. Furthermore, time-trend analyses with comparable methods are important in order to monitor the rapidly changing prevalence of these atopic diseases. Three cross sectional questionnaire-based studies of asthma and allergy in school children were conducted in the counties of Troms and Finnmark in northern Norway in 1985, 1995 and 2000. (more…)

There is much controversy as to the role of allergen exposure for the development of atopic sensitization towards this allergen. While in some studies, a clear, almost linear dose-response relation between allergen exposure and sensitization has been found, others described a bell-shaped association with higher levels of exposures relating to lower rates of atopic sensitization. Part of the discrepancy may relate to the type of allergen, since mostly cat but not house dust mite allergy allergen exposure has been shown, in some studies, to exert protective effects at higher levels of exposure. (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.