Cromolyn does not modulate human allergic skin reactions in vivo

Cromolyn pretreatment frequently reduces antigen inhalation-induced bronchospasm possibly by inhibiting mast cell degranulation and mediator release. However, the local effects of cromolyn on type I hypersensitivity skin reactions are not well understood. We studied the effect of local cromolyn on antigen-induced skin reaction, histamine release, cellular inflammatory response, and ultramicroscopic changes of mast cells in 10 ragweed-sensitized subjects. Results showed that cromolyn 2% (nonirritant dose) does not modulate ragweed-induced skin whealing response, histamine release, and ultramicroscopic changes of must cells. Thus, unlike the situation in the tracheobronchial tree, allergic skin reactions and associated events are not inhibited by local cromolyn application.