Patch testing with budesonide in serial dilutions: the significance of dose, occlusion time and reading time

Budesonide is advocated as a marker molecule for corticosteroid contact all ergy. When patch testing corticosteroids, one must consider their sensitizi ng potential but also their anti-inflammatory properties, as well as the po ssibility of different time courses for such properties. The dose-response relationship for budesonide was therefore investigated with regard to dose, oo elusion time, and reading time. 10 patients were patch tested with bude sonide in ethanol in serial dilutions from 2.0% down to 0.0002% with occlus ion times of 48, 24, and 5 h. Readings were on D2, D4, and D7. The 48-h occ lusion picked up most positive reactors, 8/10. The D4 reading (48-h occlusi on) detected most positive reactors, 8/10, and here 0.002% picked up most c ontact allergies. Late readings favoured high concentrations. The "edge eff ect" was noted for several concentrations at early readings. Due to the ind ividual corticosteroid reactivity, the dose-response relationship and the t ime courses of the elicitation and the anti-inflammatory capacity, several features may be explained, i.e., that lower concentrations may detect budes onide allergy better at early readings, that patients with an "edge reactio n" can have positive reactions to lower concentrations.