The present invention generally relates to inhibitors of DUOX1. In some aspects, an inhibitor may be applied to a subject having or being at risk for asthma or other conditions. The inhibitor may be applied by various techniques, such as pulmonary or topical delivery. In some embodiments, the inhibitor may include a peptide or other moiety having a reactive electrophile. The reactive electrophile can target cysteine or other residues within DUOX1 to inhibit its activity, e.g., by covalently binding to the residue. Other non-limiting examples of suitable inhibitors include hydroxynonenal, curcumin, sulforaphane, cinnamaldehyde, dimethyl fumarate, or phenyl vinyl sulfonate. Other aspects of the invention are generally directed to methods of making or using such inhibitors, kits involving such inhibitors, devices or formulations containing such inhibitors, or the like.