Clinical value of morphine, pholcodine and poppy seed IgE assays in drug-abusers and allergic people.

BACKGROUND The diagnosis of anaphylactic reactions due to opiates during anaesthesia can be difficult, since in most cases various drugs may have been administered. Detection of specific IgE to poppy seed might be a marker for sensitisation to opiates in allergic people and heroin-abusers. This study assessed the clinical value of morphine, pholcodine and poppy seed skin-prick and IgE determination in people suffering hypersensitivity reactions during anaesthesia or analgesia and drug-abusers with allergic symptoms. METHODS We selected heroin abusers and patients who suffered severe reactions during anaesthesia and analgesia from a database of 23,873 patients. The diagnostic yield (sensitivity, specificity and predictive value) of prick and IgE tests in determining opiate allergy was analysed. RESULTS Overall, 149 patients and 200 controls, mean age 32.9 ± 14.7 years, were included. All patients with positive prick to opiates showed positive prick and IgE to poppy seeds, but not to morphine or pholcodine IgE. Among drug-abusers, 13/42 patients (31%) presented opium hypersensitivity confirmed by challenge tests. Among non-drug abusers, sensitisation to opiates was higher in people allergic to tobacco (25%), P<.001. Prick tests and IgE against poppy seed had a good sensitivity (95.6% and 82.6%, respectively) and specificity (98.5% and 100%, respectively) in the diagnosis of opiate allergy. CONCLUSIONS Opiates may be significant allergens. Drug-abusers and people sensitised to tobacco are at risk. Both the prick and specific IgE tests efficiently detected sensitisation to opiates. The highest levels were related to more-severe clinical profiles.