Comparison of personal history with patch test results in metal allergy.

In order to compare the validity of patient personal history of contact sensitivity to metal alloys with patch test results, 160 patients with hand eczema were patch tested with a standard series according to the ICDRG after a special questionnaire. In 65%, history and patch test results were identical. Seventy-eight (48.8%) patients thought they would be allergic to metal ions, whereas the patch test revealed a positive result in only 21.3% cases. Positive history but negative test was more frequent in women; in the male group, negative history and positive patch test was the most common finding. Although 82 patients had a negative history, the patch test was positive for contact sensitivity to metal allergens in 12 of them. Both false positive patch tests and false negative histories are possible. Since many factors influence a positive patch test, not only the patient's history but also a synopsis of the anamnesis and patch testing will help to achieve the correct diagnosis of metal contact hypersensitivity.