(1) Asthma is an inflammatory respiratory disease consisting of recurrent episodes of dyspnea, coughing, and wheezing resulting from hyper-irritability of the tracheobronchial tree. The bronchiole lung tissue of asthmatics is particularly sensitive to a variety of stimuli. Overt attacks may be provoked by allergens, upper respiratory tract infections, exercise, cold air, certain medications (salicylates, nonsteroidal anti-inflammatory drugs [NSAIDs], cholinergic drugs, and beta-adrenergic blocking drugs), chemicals, smoke, and highly emotional states such as anxiety, stress, and nervousness. Though it is a worldwide problem, its exact incidence is unclear. In Japan, the prevalence has tripled since the 1960s from 1.2% to 3.14%. In the United States from 1982 to 1992, the prevalence increased about 40% from 3.47% to 4.94%. It is estimated that 10% of children are affected. Asthma is a disease primarily of children. Young asthmatics are most often male, whereas adulthood-onset disease affects women more frequently.

(2) Asthma is a multifactorial disease whose exact etiology is not well defined. Five types of asthma have been described: extrinsic asthma (allergic or atopic), intrinsic (idiosyncratic, nonallergic, or nonatopic), drug induced, exercise induced, and infectious.

(3) Allergic or extrinsic asthma is the most common form of asthma and accounts for approximately 35% of all adult cases. It is triggered by inhaled seasonal allergens such as pollens, dust, house mites, and animal danders and usually is seen in children and in young adults. There is a dose-response relationship between allergen exposure and immunoglobulin E (IgE)-mediated sensitization, positive skin testing to various allergens, as well as an associated family history of allergic diseases in these patients. During an attack, allergens interact with IgE antibodies affixed to mast cells along the tracheobronchial tree. The complex of antigen with antibody causes mast cells to degranulate and secrete vasoactive autocoids and cytokines such as bradykinins, histamine, leukotrienes, and prostaglandins. Histamine causes broncho-constriction and increased vascular permeability. The release of platelet-activating factor (PAF) sustains bronchial hyperresponsiveness. Release of E-Sekection and ICAM-1 (endothelial cell adhesion molecules), neutrophil chemotactic factor (NCF), and eosinophilic chemotactic factor of anaphylaxis (ECF-A) is responsible for recruitment of leukocytes to the airway wall, which increases tissue edema and mucous secretion. T lymphocytes prolong the inflammatory responses.

(4) Intrinsic asthma accounts for about 30% of cases of asthma. It is seldom associated with a family history of allergy nor with a known cause. Patients usually are non-responsive to skin testing and demonstrate normal IgE levels. This form of asthma is generally seen in middle-aged adults, and its onset appears to be associated with endogenous causes, such as emotional stress (implicated in at least 50% of asthmatics), gastroesophageal acid reflux, or vagal-medicated responses.

(5) Ingestion of drugs (aspirin, NSAIDs, beta-blockers, angiotensin-converting enzyme [ACE} inhibitors) or food substances (nuts, shellfish, strawberries, milk, tartrazine food dye and color yellow no. 5) can trigger asthma. Aspirin causes bronchoconstriction in about 10% of patients with asthma, and sensitivity to aspirin occurs in 30% to 40% of asthmatics who have pansinusitis and nasal polyps (triad asthmaticus). Aspirins ability to block the cyclooxygenase pathway results in bronchial spasm.

(6) Metabisulfite preservatives of foods and drugs (local anesthetics containing epinephrine) may cause wheezing, when low levels of the enzyme sulfite oxidase are present. Sulfur dioxide is produced in the absence of sulfite oxidase. The buildup of sulfur dioxide in the bronchial tree precipitates an acute asthma attack.

(7) Exercise-induced asthma is a form of asthma that is stimulated by exertional activity. Although the pathogenesis of this form of asthma is unknown, it is believed that thermal changes during inhalation of cold air provoke mucosal irritation and airway hyperactivity. Children and young adults are more severely affected owing to their high level of physical activity.

(8) Patients with infectious asthma develop bronchial constriction and increased airway resistance due to the inflammatory response of the bronchi to infection. Causative agents often are viruses, bacteria, dermatologic fungi (Trichophyton), and Mycoplasma organisms. Treatment of the infection usually improves control of the pulmonary constriction.

(1) Asthma is an inflammatory respiratory disease consisting of recurrent episodes of dyspnea, coughing, and wheezing resulting from hyper-irritability of the tracheobronchial tree. The bronchiole lung tissue of asthmatics is particularly sensitive to a variety of stimuli. Overt attacks may be provoked by allergens, upper respiratory tract infections, exercise, cold air, certain medications (salicylates, nonsteroidal anti-inflammatory drugs [NSAIDs], cholinergic drugs, and beta-adrenergic blocking drugs), chemicals, smoke, and highly emotional states such as anxiety, stress, and nervousness. Though it is a worldwide problem, its exact incidence is unclear. In Japan, the prevalence has tripled since the 1960s from 1.2% to 3.14%. In the United States from 1982 to 1992, the prevalence increased about 40% from 3.47% to 4.94%. It is estimated that 10% of children are affected. Asthma is a disease primarily of children. Young asthmatics are most often male, whereas adulthood-onset disease affects women more frequently.

(2) Asthma is a multifactorial disease whose exact etiology is not well defined. Five types of asthma have been described: extrinsic asthma (allergic or atopic), intrinsic (idiosyncratic, nonallergic, or nonatopic), drug induced, exercise induced, and infectious.

(3) Allergic or extrinsic asthma is the most common form of asthma and accounts for approximately 35% of all adult cases. It is triggered by inhaled seasonal allergens such as pollens, dust, house mites, and animal danders and usually is seen in children and in young adults. There is a dose-response relationship between allergen exposure and immunoglobulin E (IgE)-mediated sensitization, positive skin testing to various allergens, as well as an associated family history of allergic diseases in these patients. During an attack, allergens interact with IgE antibodies affixed to mast cells along the tracheobronchial tree. The complex of antigen with antibody causes mast cells to degranulate and secrete vasoactive autocoids and cytokines such as bradykinins, histamine, leukotrienes, and prostaglandins. Histamine causes broncho-constriction and increased vascular permeability. The release of platelet-activating factor (PAF) sustains bronchial hyperresponsiveness. Release of E-Sekection and ICAM-1 (endothelial cell adhesion molecules), neutrophil chemotactic factor (NCF), and eosinophilic chemotactic factor of anaphylaxis (ECF-A) is responsible for recruitment of leukocytes to the airway wall, which increases tissue edema and mucous secretion. T lymphocytes prolong the inflammatory responses.

(4) Intrinsic asthma accounts for about 30% of cases of asthma. It is seldom associated with a family history of allergy nor with a known cause. Patients usually are non-responsive to skin testing and demonstrate normal IgE levels. This form of asthma is generally seen in middle-aged adults, and its onset appears to be associated with endogenous causes, such as emotional stress (implicated in at least 50% of asthmatics), gastroesophageal acid reflux, or vagal-medicated responses.

(5) Ingestion of drugs (aspirin, NSAIDs, beta-blockers, angiotensin-converting enzyme [ACE} inhibitors) or food substances (nuts, shellfish, strawberries, milk, tartrazine food dye and color yellow no. 5) can trigger asthma. Aspirin causes bronchoconstriction in about 10% of patients with asthma, and sensitivity to aspirin occurs in 30% to 40% of asthmatics who have pansinusitis and nasal polyps (triad asthmaticus). Aspirins ability to block the cyclooxygenase pathway results in bronchial spasm.

(6) Metabisulfite preservatives of foods and drugs (local anesthetics containing epinephrine) may cause wheezing, when low levels of the enzyme sulfite oxidase are present. Sulfur dioxide is produced in the absence of sulfite oxidase. The buildup of sulfur dioxide in the bronchial tree precipitates an acute asthma attack.

(7) Exercise-induced asthma is a form of asthma that is stimulated by exertional activity. Although the pathogenesis of this form of asthma is unknown, it is believed that thermal changes during inhalation of cold air provoke mucosal irritation and airway hyperactivity. Children and young adults are more severely affected owing to their high level of physical activity.

(8) Patients with infectious asthma develop bronchial constriction and increased airway resistance due to the inflammatory response of the bronchi to infection. Causative agents often are viruses, bacteria, dermatologic fungi (Trichophyton), and Mycoplasma organisms. Treatment of the infection usually improves control of the pulmonary constriction.

(1) Asthma is an inflammatory respiratory disease consisting of recurrent episodes of dyspnea, coughing, and wheezing resulting from hyper-irritability of the tracheobronchial tree. The bronchiole lung tissue of asthmatics is particularly sensitive to a variety of stimuli. Overt attacks may be provoked by allergens, upper respiratory tract infections, exercise, cold air, certain medications (salicylates, nonsteroidal anti-inflammatory drugs [NSAIDs], cholinergic drugs, and beta-adrenergic blocking drugs), chemicals, smoke, and highly emotional states such as anxiety, stress, and nervousness. Though it is a worldwide problem, its exact incidence is unclear. In Japan, the prevalence has tripled since the 1960s from 1.2% to 3.14%. In the United States from 1982 to 1992, the prevalence increased about 40% from 3.47% to 4.94%. It is estimated that 10% of children are affected. Asthma is a disease primarily of children. Young asthmatics are most often male, whereas adulthood-onset disease affects women more frequently.

(2) Asthma is a multifactorial disease whose exact etiology is not well defined. Five types of asthma have been described: extrinsic asthma (allergic or atopic), intrinsic (idiosyncratic, nonallergic, or nonatopic), drug induced, exercise induced, and infectious.

(3) Allergic or extrinsic asthma is the most common form of asthma and accounts for approximately 35% of all adult cases. It is triggered by inhaled seasonal allergens such as pollens, dust, house mites, and animal danders and usually is seen in children and in young adults. There is a dose-response relationship between allergen exposure and immunoglobulin E (IgE)-mediated sensitization, positive skin testing to various allergens, as well as an associated family history of allergic diseases in these patients. During an attack, allergens interact with IgE antibodies affixed to mast cells along the tracheobronchial tree. The complex of antigen with antibody causes mast cells to degranulate and secrete vasoactive autocoids and cytokines such as bradykinins, histamine, leukotrienes, and prostaglandins. Histamine causes broncho-constriction and increased vascular permeability. The release of platelet-activating factor (PAF) sustains bronchial hyperresponsiveness. Release of E-Sekection and ICAM-1 (endothelial cell adhesion molecules), neutrophil chemotactic factor (NCF), and eosinophilic chemotactic factor of anaphylaxis (ECF-A) is responsible for recruitment of leukocytes to the airway wall, which increases tissue edema and mucous secretion. T lymphocytes prolong the inflammatory responses.

(4) Intrinsic asthma accounts for about 30% of cases of asthma. It is seldom associated with a family history of allergy nor with a known cause. Patients usually are non-responsive to skin testing and demonstrate normal IgE levels. This form of asthma is generally seen in middle-aged adults, and its onset appears to be associated with endogenous causes, such as emotional stress (implicated in at least 50% of asthmatics), gastroesophageal acid reflux, or vagal-medicated responses.

(5) Ingestion of drugs (aspirin, NSAIDs, beta-blockers, angiotensin-converting enzyme [ACE} inhibitors) or food substances (nuts, shellfish, strawberries, milk, tartrazine food dye and color yellow no. 5) can trigger asthma. Aspirin causes bronchoconstriction in about 10% of patients with asthma, and sensitivity to aspirin occurs in 30% to 40% of asthmatics who have pansinusitis and nasal polyps (triad asthmaticus). Aspirins ability to block the cyclooxygenase pathway results in bronchial spasm.

(6) Metabisulfite preservatives of foods and drugs (local anesthetics containing epinephrine) may cause wheezing, when low levels of the enzyme sulfite oxidase are present. Sulfur dioxide is produced in the absence of sulfite oxidase. The buildup of sulfur dioxide in the bronchial tree precipitates an acute asthma attack.

(7) Exercise-induced asthma is a form of asthma that is stimulated by exertional activity. Although the pathogenesis of this form of asthma is unknown, it is believed that thermal changes during inhalation of cold air provoke mucosal irritation and airway hyperactivity. Children and young adults are more severely affected owing to their high level of physical activity.

(8) Patients with infectious asthma develop bronchial constriction and increased airway resistance due to the inflammatory response of the bronchi to infection. Causative agents often are viruses, bacteria, dermatologic fungi (Trichophyton), and Mycoplasma organisms. Treatment of the infection usually improves control of the pulmonary constriction.

(1) Asthma is an inflammatory respiratory disease consisting of recurrent episodes of dyspnea, coughing, and wheezing resulting from hyper-irritability of the tracheobronchial tree. The bronchiole lung tissue of asthmatics is particularly sensitive to a variety of stimuli. Overt attacks may be provoked by allergens, upper respiratory tract infections, exercise, cold air, certain medications (salicylates, nonsteroidal anti-inflammatory drugs [NSAIDs], cholinergic drugs, and beta-adrenergic blocking drugs), chemicals, smoke, and highly emotional states such as anxiety, stress, and nervousness. Though it is a worldwide problem, its exact incidence is unclear. In Japan, the prevalence has tripled since the 1960s from 1.2% to 3.14%. In the United States from 1982 to 1992, the prevalence increased about 40% from 3.47% to 4.94%. It is estimated that 10% of children are affected. Asthma is a disease primarily of children. Young asthmatics are most often male, whereas adulthood-onset disease affects women more frequently.

(2) Asthma is a multifactorial disease whose exact etiology is not well defined. Five types of asthma have been described: extrinsic asthma (allergic or atopic), intrinsic (idiosyncratic, nonallergic, or nonatopic), drug induced, exercise induced, and infectious.

(3) Allergic or extrinsic asthma is the most common form of asthma and accounts for approximately 35% of all adult cases. It is triggered by inhaled seasonal allergens such as pollens, dust, house mites, and animal danders and usually is seen in children and in young adults. There is a dose-response relationship between allergen exposure and immunoglobulin E (IgE)-mediated sensitization, positive skin testing to various allergens, as well as an associated family history of allergic diseases in these patients. During an attack, allergens interact with IgE antibodies affixed to mast cells along the tracheobronchial tree. The complex of antigen with antibody causes mast cells to degranulate and secrete vasoactive autocoids and cytokines such as bradykinins, histamine, leukotrienes, and prostaglandins. Histamine causes broncho-constriction and increased vascular permeability. The release of platelet-activating factor (PAF) sustains bronchial hyperresponsiveness. Release of E-Sekection and ICAM-1 (endothelial cell adhesion molecules), neutrophil chemotactic factor (NCF), and eosinophilic chemotactic factor of anaphylaxis (ECF-A) is responsible for recruitment of leukocytes to the airway wall, which increases tissue edema and mucous secretion. T lymphocytes prolong the inflammatory responses.

(4) Intrinsic asthma accounts for about 30% of cases of asthma. It is seldom associated with a family history of allergy nor with a known cause. Patients usually are non-responsive to skin testing and demonstrate normal IgE levels. This form of asthma is generally seen in middle-aged adults, and its onset appears to be associated with endogenous causes, such as emotional stress (implicated in at least 50% of asthmatics), gastroesophageal acid reflux, or vagal-medicated responses.

(5) Ingestion of drugs (aspirin, NSAIDs, beta-blockers, angiotensin-converting enzyme [ACE} inhibitors) or food substances (nuts, shellfish, strawberries, milk, tartrazine food dye and color yellow no. 5) can trigger asthma. Aspirin causes bronchoconstriction in about 10% of patients with asthma, and sensitivity to aspirin occurs in 30% to 40% of asthmatics who have pansinusitis and nasal polyps (triad asthmaticus). Aspirins ability to block the cyclooxygenase pathway results in bronchial spasm.

(6) Metabisulfite preservatives of foods and drugs (local anesthetics containing epinephrine) may cause wheezing, when low levels of the enzyme sulfite oxidase are present. Sulfur dioxide is produced in the absence of sulfite oxidase. The buildup of sulfur dioxide in the bronchial tree precipitates an acute asthma attack.

(7) Exercise-induced asthma is a form of asthma that is stimulated by exertional activity. Although the pathogenesis of this form of asthma is unknown, it is believed that thermal changes during inhalation of cold air provoke mucosal irritation and airway hyperactivity. Children and young adults are more severely affected owing to their high level of physical activity.

(8) Patients with infectious asthma develop bronchial constriction and increased airway resistance due to the inflammatory response of the bronchi to infection. Causative agents often are viruses, bacteria, dermatologic fungi (Trichophyton), and Mycoplasma organisms. Treatment of the infection usually improves control of the pulmonary constriction.

(1) Asthma is an inflammatory respiratory disease consisting of recurrent episodes of dyspnea, coughing, and wheezing resulting from hyper-irritability of the tracheobronchial tree. The bronchiole lung tissue of asthmatics is particularly sensitive to a variety of stimuli. Overt attacks may be provoked by allergens, upper respiratory tract infections, exercise, cold air, certain medications (salicylates, nonsteroidal anti-inflammatory drugs [NSAIDs], cholinergic drugs, and beta-adrenergic blocking drugs), chemicals, smoke, and highly emotional states such as anxiety, stress, and nervousness. Though it is a worldwide problem, its exact incidence is unclear. In Japan, the prevalence has tripled since the 1960s from 1.2% to 3.14%. In the United States from 1982 to 1992, the prevalence increased about 40% from 3.47% to 4.94%. It is estimated that 10% of children are affected. Asthma is a disease primarily of children. Young asthmatics are most often male, whereas adulthood-onset disease affects women more frequently.

(2) Asthma is a multifactorial disease whose exact etiology is not well defined. Five types of asthma have been described: extrinsic asthma (allergic or atopic), intrinsic (idiosyncratic, nonallergic, or nonatopic), drug induced, exercise induced, and infectious.

(3) Allergic or extrinsic asthma is the most common form of asthma and accounts for approximately 35% of all adult cases. It is triggered by inhaled seasonal allergens such as pollens, dust, house mites, and animal danders and usually is seen in children and in young adults. There is a dose-response relationship between allergen exposure and immunoglobulin E (IgE)-mediated sensitization, positive skin testing to various allergens, as well as an associated family history of allergic diseases in these patients. During an attack, allergens interact with IgE antibodies affixed to mast cells along the tracheobronchial tree. The complex of antigen with antibody causes mast cells to degranulate and secrete vasoactive autocoids and cytokines such as bradykinins, histamine, leukotrienes, and prostaglandins. Histamine causes broncho-constriction and increased vascular permeability. The release of platelet-activating factor (PAF) sustains bronchial hyperresponsiveness. Release of E-Sekection and ICAM-1 (endothelial cell adhesion molecules), neutrophil chemotactic factor (NCF), and eosinophilic chemotactic factor of anaphylaxis (ECF-A) is responsible for recruitment of leukocytes to the airway wall, which increases tissue edema and mucous secretion. T lymphocytes prolong the inflammatory responses.

(4) Intrinsic asthma accounts for about 30% of cases of asthma. It is seldom associated with a family history of allergy nor with a known cause. Patients usually are non-responsive to skin testing and demonstrate normal IgE levels. This form of asthma is generally seen in middle-aged adults, and its onset appears to be associated with endogenous causes, such as emotional stress (implicated in at least 50% of asthmatics), gastroesophageal acid reflux, or vagal-medicated responses.

(5) Ingestion of drugs (aspirin, NSAIDs, beta-blockers, angiotensin-converting enzyme [ACE} inhibitors) or food substances (nuts, shellfish, strawberries, milk, tartrazine food dye and color yellow no. 5) can trigger asthma. Aspirin causes bronchoconstriction in about 10% of patients with asthma, and sensitivity to aspirin occurs in 30% to 40% of asthmatics who have pansinusitis and nasal polyps (triad asthmaticus). Aspirins ability to block the cyclooxygenase pathway results in bronchial spasm.

(6) Metabisulfite preservatives of foods and drugs (local anesthetics containing epinephrine) may cause wheezing, when low levels of the enzyme sulfite oxidase are present. Sulfur dioxide is produced in the absence of sulfite oxidase. The buildup of sulfur dioxide in the bronchial tree precipitates an acute asthma attack.

(7) Exercise-induced asthma is a form of asthma that is stimulated by exertional activity. Although the pathogenesis of this form of asthma is unknown, it is believed that thermal changes during inhalation of cold air provoke mucosal irritation and airway hyperactivity. Children and young adults are more severely affected owing to their high level of physical activity.

(8) Patients with infectious asthma develop bronchial constriction and increased airway resistance due to the inflammatory response of the bronchi to infection. Causative agents often are viruses, bacteria, dermatologic fungi (Trichophyton), and Mycoplasma organisms. Treatment of the infection usually improves control of the pulmonary constriction.

(1) Asthma is an inflammatory respiratory disease consisting of recurrent episodes of dyspnea, coughing, and wheezing resulting from hyper-irritability of the tracheobronchial tree. The bronchiole lung tissue of asthmatics is particularly sensitive to a variety of stimuli. Overt attacks may be provoked by allergens, upper respiratory tract infections, exercise, cold air, certain medications (salicylates, nonsteroidal anti-inflammatory drugs [NSAIDs], cholinergic drugs, and beta-adrenergic blocking drugs), chemicals, smoke, and highly emotional states such as anxiety, stress, and nervousness. Though it is a worldwide problem, its exact incidence is unclear. In Japan, the prevalence has tripled since the 1960s from 1.2% to 3.14%. In the United States from 1982 to 1992, the prevalence increased about 40% from 3.47% to 4.94%. It is estimated that 10% of children are affected. Asthma is a disease primarily of children. Young asthmatics are most often male, whereas adulthood-onset disease affects women more frequently.

(2) Asthma is a multifactorial disease whose exact etiology is not well defined. Five types of asthma have been described: extrinsic asthma (allergic or atopic), intrinsic (idiosyncratic, nonallergic, or nonatopic), drug induced, exercise induced, and infectious.

(3) Allergic or extrinsic asthma is the most common form of asthma and accounts for approximately 35% of all adult cases. It is triggered by inhaled seasonal allergens such as pollens, dust, house mites, and animal danders and usually is seen in children and in young adults. There is a dose-response relationship between allergen exposure and immunoglobulin E (IgE)-mediated sensitization, positive skin testing to various allergens, as well as an associated family history of allergic diseases in these patients. During an attack, allergens interact with IgE antibodies affixed to mast cells along the tracheobronchial tree. The complex of antigen with antibody causes mast cells to degranulate and secrete vasoactive autocoids and cytokines such as bradykinins, histamine, leukotrienes, and prostaglandins. Histamine causes broncho-constriction and increased vascular permeability. The release of platelet-activating factor (PAF) sustains bronchial hyperresponsiveness. Release of E-Sekection and ICAM-1 (endothelial cell adhesion molecules), neutrophil chemotactic factor (NCF), and eosinophilic chemotactic factor of anaphylaxis (ECF-A) is responsible for recruitment of leukocytes to the airway wall, which increases tissue edema and mucous secretion. T lymphocytes prolong the inflammatory responses.

(4) Intrinsic asthma accounts for about 30% of cases of asthma. It is seldom associated with a family history of allergy nor with a known cause. Patients usually are non-responsive to skin testing and demonstrate normal IgE levels. This form of asthma is generally seen in middle-aged adults, and its onset appears to be associated with endogenous causes, such as emotional stress (implicated in at least 50% of asthmatics), gastroesophageal acid reflux, or vagal-medicated responses.

(5) Ingestion of drugs (aspirin, NSAIDs, beta-blockers, angiotensin-converting enzyme [ACE} inhibitors) or food substances (nuts, shellfish, strawberries, milk, tartrazine food dye and color yellow no. 5) can trigger asthma. Aspirin causes bronchoconstriction in about 10% of patients with asthma, and sensitivity to aspirin occurs in 30% to 40% of asthmatics who have pansinusitis and nasal polyps (triad asthmaticus). Aspirins ability to block the cyclooxygenase pathway results in bronchial spasm.

(6) Metabisulfite preservatives of foods and drugs (local anesthetics containing epinephrine) may cause wheezing, when low levels of the enzyme sulfite oxidase are present. Sulfur dioxide is produced in the absence of sulfite oxidase. The buildup of sulfur dioxide in the bronchial tree precipitates an acute asthma attack.

(7) Exercise-induced asthma is a form of asthma that is stimulated by exertional activity. Although the pathogenesis of this form of asthma is unknown, it is believed that thermal changes during inhalation of cold air provoke mucosal irritation and airway hyperactivity. Children and young adults are more severely affected owing to their high level of physical activity.

(8) Patients with infectious asthma develop bronchial constriction and increased airway resistance due to the inflammatory response of the bronchi to infection. Causative agents often are viruses, bacteria, dermatologic fungi (Trichophyton), and Mycoplasma organisms. Treatment of the infection usually improves control of the pulmonary constriction.

(1) Asthma is an inflammatory respiratory disease consisting of recurrent episodes of dyspnea, coughing, and wheezing resulting from hyper-irritability of the tracheobronchial tree. The bronchiole lung tissue of asthmatics is particularly sensitive to a variety of stimuli. Overt attacks may be provoked by allergens, upper respiratory tract infections, exercise, cold air, certain medications (salicylates, nonsteroidal anti-inflammatory drugs [NSAIDs], cholinergic drugs, and beta-adrenergic blocking drugs), chemicals, smoke, and highly emotional states such as anxiety, stress, and nervousness. Though it is a worldwide problem, its exact incidence is unclear. In Japan, the prevalence has tripled since the 1960s from 1.2% to 3.14%. In the United States from 1982 to 1992, the prevalence increased about 40% from 3.47% to 4.94%. It is estimated that 10% of children are affected. Asthma is a disease primarily of children. Young asthmatics are most often male, whereas adulthood-onset disease affects women more frequently.

(2) Asthma is a multifactorial disease whose exact etiology is not well defined. Five types of asthma have been described: extrinsic asthma (allergic or atopic), intrinsic (idiosyncratic, nonallergic, or nonatopic), drug induced, exercise induced, and infectious.

(3) Allergic or extrinsic asthma is the most common form of asthma and accounts for approximately 35% of all adult cases. It is triggered by inhaled seasonal allergens such as pollens, dust, house mites, and animal danders and usually is seen in children and in young adults. There is a dose-response relationship between allergen exposure and immunoglobulin E (IgE)-mediated sensitization, positive skin testing to various allergens, as well as an associated family history of allergic diseases in these patients. During an attack, allergens interact with IgE antibodies affixed to mast cells along the tracheobronchial tree. The complex of antigen with antibody causes mast cells to degranulate and secrete vasoactive autocoids and cytokines such as bradykinins, histamine, leukotrienes, and prostaglandins. Histamine causes broncho-constriction and increased vascular permeability. The release of platelet-activating factor (PAF) sustains bronchial hyperresponsiveness. Release of E-Sekection and ICAM-1 (endothelial cell adhesion molecules), neutrophil chemotactic factor (NCF), and eosinophilic chemotactic factor of anaphylaxis (ECF-A) is responsible for recruitment of leukocytes to the airway wall, which increases tissue edema and mucous secretion. T lymphocytes prolong the inflammatory responses.

(4) Intrinsic asthma accounts for about 30% of cases of asthma. It is seldom associated with a family history of allergy nor with a known cause. Patients usually are non-responsive to skin testing and demonstrate normal IgE levels. This form of asthma is generally seen in middle-aged adults, and its onset appears to be associated with endogenous causes, such as emotional stress (implicated in at least 50% of asthmatics), gastroesophageal acid reflux, or vagal-medicated responses.

(5) Ingestion of drugs (aspirin, NSAIDs, beta-blockers, angiotensin-converting enzyme [ACE} inhibitors) or food substances (nuts, shellfish, strawberries, milk, tartrazine food dye and color yellow no. 5) can trigger asthma. Aspirin causes bronchoconstriction in about 10% of patients with asthma, and sensitivity to aspirin occurs in 30% to 40% of asthmatics who have pansinusitis and nasal polyps (triad asthmaticus). Aspirins ability to block the cyclooxygenase pathway results in bronchial spasm.

(6) Metabisulfite preservatives of foods and drugs (local anesthetics containing epinephrine) may cause wheezing, when low levels of the enzyme sulfite oxidase are present. Sulfur dioxide is produced in the absence of sulfite oxidase. The buildup of sulfur dioxide in the bronchial tree precipitates an acute asthma attack.

(7) Exercise-induced asthma is a form of asthma that is stimulated by exertional activity. Although the pathogenesis of this form of asthma is unknown, it is believed that thermal changes during inhalation of cold air provoke mucosal irritation and airway hyperactivity. Children and young adults are more severely affected owing to their high level of physical activity.

(8) Patients with infectious asthma develop bronchial constriction and increased airway resistance due to the inflammatory response of the bronchi to infection. Causative agents often are viruses, bacteria, dermatologic fungi (Trichophyton), and Mycoplasma organisms. Treatment of the infection usually improves control of the pulmonary constriction.