Respiratory symptoms in ispaghula-allergic nurses after oral challenge with ispaghula suspension

Ispaghula powder, which is used as a component in bulk laxatives, is known to induce allergic reactions when inhaled by occupationally exposed persons. We have tested whether nurses sensitized by inhalation could get allergic symptoms when challenged by eating ispaghula. Of six nurses tested, all developed symptoms from the airways, one of them even pronounced ones requiring treatment. In all cases the dose required to produce symptoms was below the single dose of ispaghula used as a laxative.