Patch test reactions to mite antigens: a GERDA* multicentre study

We performed patch tests with Dermatophagoides pteronyssinus (Dp) antigen from 2 different sources in 355 non‐randomly selected patients with atopic dermatitis(AD) and 398 subjects of a control group. The study demonstrated that contact sensitization to mites occurred in an appreciable% of AD cases(20.8%). Using commonly available assay products. The differences recorded between the 2 materials tested were related to the concentration of P1 antigen. Non‐atopic patients rarely showed positive reactions to Dp (0.75%), when strict criteria for readings were applied and if 2 readings were performed, Patients with positive patch tests did not necessarily show positive immediate skin tests. It would be useful to carry out tests systematically in atopic patients, even if it is not yet known what modern treatment would be best for the patient. Laboratories still do not provide standardized house dust mite preparations measuring and codifying their biological acitivity for use in patch of better test materials, in syringes with homogeneous dispersion and concentration.