Venom skin testing and alteration of RAST levels

Since the availability of insect venoms for skin testing, recommendations suggest skin testing any person who has had a systemic reaction to a stinging insect with all venoms available for diagnostic purposes. Considering the possibility for actual sensitization with such a procedure, 30 children had RAST testing obtained before, immediately following and several weeks after skin testing with venoms for honey bee, wasp, yellow jacket and hornets. We found 53% of our patients had elevations in either immediate or delayed RAST levels of over 120% and this increase was believed to be significant. While the clinical significance is not directly interpretable as none of these patients were subsequently stung, we felt it may suggest that they are at greater risk for a future reaction. The increase was most often observed in RAST venom levels where corresponding skin tests had been negative. We therefore conclude that skin testing should not be arbitrarily performed and perhaps skin testing with a minimal number of venoms would be appropriate (especially when the responsible insect is known). Lastly, we believe that closing monitoring of RAST levels following skin testing may be important.