Exacerbations of severe asthma while on Anti-IL5 biologicals.

Anti-interleukin 5 (IL5) and anti-IL5 receptor alpha monoclonal antibodies markedly decrease airway and peripheral blood eosinophil numbers; thus, they are highly effective in reducing asthma exacerbations. Nonetheless, flare-ups are not completely ameliorated on these biologics. There is modest evidence regarding the nature of these exacerbations, where severe asthmatics on these therapies could still have serious exacerbations that are non-eosinophilic. Using illustrative clinical case scenarios, we highlight the importance of carefully characterizing asthmatics at the time of exacerbation and recognizing neutrophilic causes of exacerbations. This is important to manage these exacerbations. While an eosinophilic exacerbation may benefit with more glucocorticosteroids or by switching to another anti-IL5 mAb, a non-eosinophilic exacerbation will likely not. An infective exacerbation needs to be recognized, the pathogen identified and treated with the appropriate anti-microbial agent.