Oral desensitization in papular urticaria in children.

Papular urticaria (PU) is among the commonest skin ailments in children. Induced specific desensitization to insect bites is theoretically an effective means of prevention of PU. In this double blind placebo controlled study, an oral vaccine prepared from insect saliva was compared with placebo (stable vaccine solvent). Vaccine and placebo effectiveness were tested by counting active PU lesions, serum eosinophils, and IgE, before and after 4 months of treatment. Statistically significant differences between oral vaccine and placebo were not found in the clinical or the immunological variables tested. We conclude that, although a lack of oral vaccine efficacy was suspected, larger study samples are needed to strengthen our conclusion.