Reactivity at edges of corticosteroid patch tests may be an indicator of astrong positive test response

Background: The importance of the reactivity at the edges of corticosteroid patch tests is unknown. Objective: To study the clinical importance of edg e reactivity in budesonide patch tests. Methods: Ten subjects previously po sitive for budesonide patch tests were retested with 0.1% budesonide in Fin n Chambers(R) and with budesonide-printed polyester squares in serial doses (150-0.074 mu g/cm(2)). Six exposure periods were used for each polyester square dose (3 h to 4 days). Tests were followed up to 11 days. Doubtful or weakly visible reactivity at the test edges was assessed additionally by t est perfusion assessments. Results: Nine of 10 subjects reacted with some e dge reactivity and later exhibited positive reactions. Perfusion assessment s helped to confirm early edge reactivity. Some allergic subjects showed ed ge reactivity only at high doses, while longer applications were required f or weaker doses. Conclusion: Edge reactivity may be an indicator of a stron g suppressed test response.