New results and some remarks to the "angry back syndrome"

Forty patients who showed more than two positive reactions to a standard patch test series of 26 substances were retested subsequently with the allergens that had given positive responses; 13 of 151 reactions were negative in the repetition, that is, 8.6% in comparison with 42% in the investigations of Mitchell (1977) in which 38 of 90 reactions could not be reproduced. Possible causes of this difference are discussed.