Reappraisal of intracutaneous tests in the diagnosis of reaginic allergy.

In an attempt to determine the clinical relevance of positive intracutaneous tests when epicutaneous tests are negative, 34 patients with symptoms of perennial rhinitis who had negative epicutaneous but positive intracutaneous tests were evaluated by radioallergosorbent (RAST) test, nasal provocation (NP) tests and leukocyte histamine release (LHR) assay. Nineteen patients with perennial rhinitis who had positive epicutaneous tests and 13 normal healthy volunteers were also studied as positive and negative controls, respectively. None of the 34 patients with negative epicutaneous but positive intracutaneous tests had positive RASTs or LHR assays, but 1 patient had a positive NP test. In contrast, of the 19 patients with positive epicutaneous tests, 12 patients had positive RASTs, 17 had positive LHR assays, and 17 had positive NP tests. In the negative control group of 13 subjects, none had positive RAST, LHR assays, or NP tests, although 3 subjects showed positive intracutaneous tests. These results indicate that when epicutaneous tests are negative in patients with perennial rhinitis, positive intracutaneous tests are not likely to indicate the presence of reaginic allergy.