[Urticarial skin reaction to codeine, a measure of mast cell reactivity]

The reactivity of skin mast cells was tested in 86 probands. Introduction of various concentrations of codeine phosphate, either by intradermal injection or by prick test, produced an immediate wheal and flare response. Since the codeine skin test depends on both release of and response to histamine, it may be more useful than the conventional skin test with histamine for assessment of skin reactivity, and also for preliminary evaluation of anti-allergic agents in man.