Asthma is described as an chronic infection which shows inflammation in the pulmonary airway and bronchial hyperresponsiveness to an allergen resulting in asthmatic conditions.inflammatory cells are accumulated in respiratory bronchioles.
Physiologically, allergen inhaled results in provocation of the inflammatory system of the respiratory system resulting in increased secreation of inflammatory mediators such as methacalmine and histamine. Release of histamine from the mast cells results in activation of the prostaglandins and leukotrienes.In addition to that cytokines are also released from the mast cells which leads to Increased vascular permeabilty,mucous secretion, bronchospasm, and wheezing.these are the signs of EARLY ASTHMATIC ATTACK.
Triggering factors that results in blockage of the pulmonary airway include cold air, exercise, viral upper respiratory infection, cigarette smoke, and respiratory allergens. Bronchial provocation with allergen induces a prompt early phase immunoglobulin E (IgE)-mediated decrease in bronchial airflow. Initially there is an increase in the leukocyte count in the pulmonary ares with help of CD4+ cells. The activated T-lymphocytes also direct the release of inflammatory mediators from eosinophils, mast cells, and lymphocytes. The cross-linkage of two IgE molecules by allergen causes mast cells to degranulate, releasing histamine, leukotrienes, and other mediators that perpetuate the airway inflammation. Histolopathology of the bronchial airway might shows an inflammatory cells consisting of eosonophis, mast cells, lymphocytes, monocytes and neutrophils.This is the sign of LATE ASTHMATIC ATTACK.