EMLA CREAM FOR PAIN REDUCTION IN DIAGNOSTIC ALLERGY SKIN TESTING - EFFECTS ON WHEAL AND FLARE RESPONSES

Background: The use of a topical anesthetic cream containing prilocain e and lidocaine (EMLA) has been considered to reduce the pain of diagn ostic allergy skin testing, but the effects of the cream on interpreta tion of skin tests is unclear. Objective: To determine the effects of the cream for pain reduction using prick and ID skin tests and for pos sible alteration of wheal and flare responses to allergen, saline, and histamine. Methods: In a randomized, double-masked, placebo-controlle d design, 20 adult volunteers with a history of positive allergen test s had EMLA and placebo cream placed according to the manufacturer's re commendations on the volar aspect of the arms. Paired skin tests were placed and subjects rated the tests on a pain scale from 0 to 5 and av erage wheal and flare diameters were determined. Results: Mean pain sc ores (+/- SEM) were significantly reduced from 2.5 +/- 0.7 to 1.1 +/- 0.6 for prick tests (n = 20, P < .001) and from 3.2 +/- 0.9 to 1.13 +/ - 0.9 for intradermal (ID) tests (n = 58, P < .001). The wheal sizes f or allergen prick tests, allergen TD tests, and histamine ID tests wer e identical in comparing placebo to EMLA-treated skin. Flare responses were reduced on the actively treated skin, on average, as follows: al lergen skin tests- 52% (P < .001), and histamine- 40% (P < .001). fn n ine tests there was complete suppression of the flare response, all on the EMLA treated skin. Conclusions: EMLA significantly reduced the pa in associated with diagnostic allergy skin testing and with no effect on the size of the wheal response. It reduces the flare response, in s ome cases inhibiting it completely, which must be taken into considera tion in interpreting results.