In an asthmatic patient, what causes increased airway resistance following exposure to an allergen?

💡 Explanation

Mast cell degranulation leads to the release of histamine and leukotrienes, causing bronchoconstriction and inflammation, which increases airway resistance, because these mediators directly stimulate smooth muscle contraction. Therefore, the answer is mast cell degranulation, rather than epithelial hyperplasia or surfactant deficiency, which are not primary mechanisms in acute asthma exacerbations.

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