Bronchial inhalation challenge procedures with allergens and other bronchoconstrictor substances

Antigen inhalation challenges nowadays are most commonly used as an investigative tool to better understand the pathophysiology of asthma and possible blocking effects of immunotherapy. However, they also serve to better define the role of specific allergens in asthma, and as a possible substitution for skin tests when they cannot be performed. Of particular interest in the literature has been the late asthmatic response and the increase in so-called nonspecific reactivity that follows. When a new pharmaceutical agent is studied, its ability to block both the late phase and subsequent hyperreactivity is presumptive evidence for effectiveness. The more commonly employed challenges with bronchoconstrictive substances, such as methacholine and histamine, have been used to assess atypical asthma, better define occupational asthma and a way to quantitate hyperreactive airways disease. Other bronchoconstrictive agents that have been employed include acetylcholine, carbamylcholine, serotonin, prostaglandins and leukotrienes. Since any bronchoconstrictor agent has a potential for making a patient uncomfortable due to the induced bronchoconstriction, necessary equipment for anaphylaxis should be available and trained personnel should be aware of possible adverse reactions which can occur uncommonly.