Opiate-sensitivity: clinical characteristics and the role of skin prick testing.
BACKGROUND
The value of skin prick testing in opiate-sensitive individuals is uncertain as opiates cause non-specific weals by direct degranulation of mast cells.


OBJECTIVE
To define whether skin prick test (SPT) responses to opiates in opiate-sensitive individuals are different to those seen in the normal population and to describe the clinical characteristics of this group of subjects.


METHODS
The SPT responses of eight opiate-sensitive subjects to morphine 10 mg/mL, pethidine (meperidine) 50 mg/mL and papaveretum 15.4 mg/mL at four different concentrations (undiluted, 1/10, 1/50 and 1/100) were compared with the responses of 100 (32 atopic) non-opiate-sensitive control subjects. Four of the opiate-sensitive subjects had a clinical history of asthma, rhinitis or urticaria on occupational exposure to morphine. One subject developed urticaria with codeine, one developed urticaria and asthma with morphine and diamorphine and two subjects reacted to intravenous papaveretum with anaphylaxis or urticaria. Five out of the eight cases had opiate sensitivity confirmed by single-blind placebo-controlled oral challenge.


RESULTS
Skin prick tests to all three opiates were not significantly different when the eight opiate-sensitive subjects were compared with either the entire normal control group or the subgroup of 47 definite opiate-tolerant controls that had previously received opiates for clinical indications. Furthermore, there were no significant differences in size of opiate SPT responses between atopic and non-atopic control subjects. In the control subjects, there was a positive correlation in SPT weal size between the three opiates.


CONCLUSIONS
Skin prick testing is not useful in the diagnosis of opiate sensitivity and placebo-controlled challenge should be considered.
Nasser
S M
SM
Department of Medicine, University of Cambridge Clinical School, Addenbrooke's Hospital, Hills Road, Cambridge CB2 2QQ, UK.
Ewan
P W
PW
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000485:Allergens; D001249:Asthma / Q000276:immunology; D003061:Codeine / Q000276:immunology; D004342:Drug Hypersensitivity / Q000175:diagnosis* / Q000276:immunology; D005260:Female; D003932:Heroin / Q000276:immunology; D006801:Humans; D008297:Male; D008614:Meperidine / Q000276:immunology; D008875:Middle Aged; D009020:Morphine / Q000276:immunology; D009294:Narcotics / Q000276:immunology*; D009784:Occupational Diseases / Q000276:immunology; D009892:Opium / Q000276:immunology; D012220:Rhinitis / Q000276:immunology; D012882:Skin Tests / Q000379:methods*; D014581:Urticaria / Q000276:immunology
D000485:Allergens; D009294:Narcotics; D003932:Heroin; D009020:Morphine; D009892:Opium; D008614:Meperidine; D003061:Codeine