[Incidence and prevention of allergic reactions following chemonucleolysis with chymopapain]

Allergic reaction following chemonucleolysis with chymopapain is responsible for half of all known complications of this treatment. Although the incidence of allergic reactions is comparatively low one should not underestimate the danger involved. If chemonucleolysis is performed under local anaesthesia, the risk of an anaphylactic reaction is reduced. If no pre-operative test methods are available, the patient risk can be considerably lessened by suitable premedication and by keeping anti-allergics within easy reach during intradiscal therapy. Exclusion of patients who have a previous history of allergy from chemonucleolysis will not result in additional safety. The specificity of the serological tests is very high, but their sensitivity and reliability in respect of prediction of an allergic reaction with positive or negative test result is comparatively low. They take up a lot of time (24 hours) and require skilled personnel trained in laboratory chemistry. The chymopapain prick test is simple to perform and the result of the test rapidly available (15 minutes). The danger of allergic reactions to the prick test itself is negligibly small, as experience has shown. At the present time no comparative tests are available between serological tests and skin tests in a large group of patients, so that we can say something about the reliability only on the basis of empirical data. Of the 352 test-negative patients investigated so far, none had an allergic immediate reaction to chymopapain. Even if we take the possibility of false positive skin tests into consideration, we believe that it would not be appropriate with a positive skin test to perform chemonucleolysis.