Diagnostic significance of late cutaneous allergic responses and their correlation with radioallergosorbent test.

In order to study the clinical significance of late cutaneous allergic responses 178 intracutaneous tests were done on the forearm of forty-three allergic patients with perennial allergy and twelve patients with pollen allergy. The allergen concentration was chosen to give a moderate immediate response with a weal diameter of about 15 mm. Late cutaneous allergic responses (LCAR) were elicited in eighty-two intracutaneous tests in thirty-one patients with perennial allergy and in nine intracutaneous tests in eight patients with pollen allergy, with almost all the allergens frequently responsible for allergy in this area. Their occurrence was found to be related to the size of the immediate reaction. Almost all the patients showing LCAR had positive provocation tests and were clinically sensitive to the corresponding allergen.