The role of intradermal skin testing in inhalant allergy

Objective: To provide an overview of the role of intradermal skin testing (IDST) in inhalant allergy. Data Sources: A literature search was conducted in MEDLINE to identify peer-reviewed articles related to IDST using the following keywords: skin testing, intradermal, intracutaneous, aeroallergen, and inhalant allergen. In addition, references cited within these articles were also reviewed. Study Selection: Articles were selected based on their relevance to the topic. Results: The use of IDST for inhalant allergy varies widely among allergists. When performed, it is necessary to use a 100- to 1,000-fold dilution from the stock allergen extract. IDST is used routinely in the standardization of extracts in the United States. With a negative skin prick test result, a positive IDST result has low agreement with in vitro and challenge results and generally adds little to the diagnostic evaluation. In contrast, a negative IDST result generally has a high negative predictive value. Only a few inhalant allergens have been evaluated with challenge models for IDST. A summary of the data is also presented in tabular form. Conclusions: Most of the literature suggests that with a negative skin prick test result, a positive IDST result adds little to the diagnostic evaluation of inhalant allergy. However, additional studies are necessary using challenge models for less potent and nonstandardized inhalant allergens (molds, trees, dog, weeds).