Value of history and testing in suspected contact dermatitis

Testing with a routine series of 20 compounds was performed in 140 patients with suspected allergic contact dermatitis. In 49 patients 97 positive test reactions were found. The number of expected and unexpected test reactions was about the same. When unexpected test reactions were found eczematogenic exposures to the allergens could be traced in one half of the cases. The study demonstrates the diagnostic value of testing, but the actual clinical significance of testing must be the subject of further investigations.