Screening for delayed hypersensitivity in Italian children: multicentric study by multitest skin testing.

The Multitest skin test allows the simultaneous intradermal application of seven standardized recall antigens in a reproducible manner. Response reading is based on a scoring system that distinguishes between normal and diminished delayed hypersensitivity (DH). To determine incidence and size of DH responses for each antigen in relation to age and sex in healthy Italian children, a multicentric study was performed on a representative paediatric population of 491 subjects (285 males and 296 females) aged from 4 months to 16 years. In both sexes DH reactivity as measured by score and number of positive responses increased significantly with age. The incidence of anergy was 8.8% for the whole population and decreased significantly with age in both sexes. Incidence of positive responses was highest for tetanus and diphteria toxoids, intermediate for Candida, Proteus and Streptococcus, and lowest for tuberculin and Trichophyton antigens. There was no significant difference between sexes in the incidence of positive response to each antigen.