Incidence and risk factors for latent sensitization to chymopapain: predictive skin-prick tests in 700 candidates for chemonucleolysis.

Seven hundred patients were investigated prospectively before undergoing chemonucleolysis. A past history of allergy and/or previous exposure to papain, either in food, beverages or drugs, was sought, and a skin-prick test with chymopapain was performed. Based on the results obtained, the subjects were classified into four groups: Group I--225 non-atopic non-papain-exposed subjects; Group II--285 non-atopic papain-exposed subjects; Group III--69 atopic non-papain-exposed subjects; and Group IV--121 atopic papain-exposed subjects. Latent sensitization to papain was observed in 0.4% of subjects in Group I, 3.16% in Group II, 5.8% in Group III and 7.4% in Group IV. The odds ratios were 13.8 for atopy and 7.3 for exposure to papain. Interaction between atopy and papain exposure did not result in a significantly greater risk. Neither sex nor age nor a history of a previous drug reaction were risk factors. Only one patient out of the 23 who were sensitive to papain had no risk factor. The 677 skin-test negative patients then underwent chemonucleolysis and none of them had an anaphylactic reaction. This was significantly less frequent: (P = 0.04) than the incidence in a random population (0.45%). Prick tests performed 6 weeks and 6 months after chemonucleolysis revealed newly acquired sensitization in 36% of the patients. Atopy was not a risk factor for this event.(ABSTRACT TRUNCATED AT 250 WORDS)