Skin reactions to histamine and compound 48/80 in chronic urticaria: a diagnostic tool?

Chronic urticaria is a changeable disorder with an unknown length of duration. Thus, an objective method which could differentiate affected individuals from healthy individuals and with predictive information about when treatment might be diminished or stopped would be desirable. Therefore, we have tried to achieve this by means of Multitest, a device rendering good skin reaction reproduction and reagents such as 48/80 Compound (a nonspecific mast cell degranulator) and histamine. These substances were applied on 1 to 10(3) Mol concentrations for histamine and 10 to 10(3) mg/ml as the degranulating agent. Sixteen patients and 10 controls were submitted to this test, variables such as drugs modifying wheals, time of the day, age range and skin area were controlled. In both groups a clear dose-response relationship was demonstrated by either reagent. However, an excessive individual variability appeared in each sample and significant differences could not be shown so much for sensitivity or for reactivity (responses by the lowest and the highest concentrations, respectively). We conclude that the lack of differences observed on cutaneous mast cell "releasability" and skin vessels response to histamine in chronic urticaria patients could be due to a rather outstanding role of other cells and its mediators, in mechanisms of that chronic disease.