Asthma

During an asthma episode, inflamed airways react to environmental triggers such as smoke, dust, or pollen. The airways narrow and produce excess mucus, making it difficult to breathe. In essence, asthma is the result of an immune... See more » During an asthma episode, inflamed airways react to environmental triggers such as smoke, dust, or pollen. The airways narrow and produce excess mucus, making it difficult to breathe. In essence, asthma is the result of an immune response in the bronchial airways.[6] The airways of asthmatics are "hypersensitive" to certain triggers, also known as stimuli (see below). In response to exposure to these triggers, the bronchi (large airways) contract into spasm (an "asthma attack"). Inflammation soon follows, leading to a further narrowing of the airways and excessive mucus production, which leads to coughing and other breathing difficulties. [edit] Stimuli There are about ten different categories of stimuli: * Allergenic air pollution, from nature, typically inhaled, which include waste from common household pests, such as the house dust mite and cockroach, grass pollen, mould spores, and pet epithelial cells; * Medications, including aspirin[7], β-adrenergic antagonists (beta blockers), and penicillin. * Food allergies such as milk, peanuts, and eggs. However, asthma is rarely the only symptom, and not all people with food or other allergies have asthma. * Use of fossil fuel related allergenic air pollution, such as ozone, smog, summer smog, nitrogen dioxide, and sulfur dioxide, which is thought to be one of the major reasons for the high prevalence of asthma in urban areas; * Various industrial compounds and other chemicals, notably sulfites; chlorinated swimming pools generate chloramines—monochloramine (NH2Cl), dichloramine (NHCl2) and trichloramine (NCl3)—in the air around them, which are known to induce asthma.[8] * Early childhood infections, especially viral respiratory infections. However, persons of any age can have asthma triggered by colds and other respiratory infections even though their normal stimuli might be from another category (e.g. pollen) and absent at the time of infection. 80% of asthma attacks in adults and 60% in children are caused by respiratory viruses. * Exercise, the effects of which differ somewhat from those of the other triggers; * Allergenic indoor air pollution from newsprint & other literature such as, junk mail leaflets & glossy magazines (in some countries). * Hormonal changes in adolescent girls and adult women associated with their menstrual cycle can lead to a worsening of asthma. Some women also experience a worsening of their asthma during pregnancy whereas others find no significant changes, and in other women their asthma improves during their pregnancy. * Emotional stress which is poorly understood as a trigger. See less »

The word 'asthma' is derived from the Greek aazein, meaning "sharp breath." The word first appears in Homer's Iliad;[3] Hippocrates was the first to use it in reference to the medical condition, in 450 BC. Hippocrates thought that...

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