Proposal of abolition of the skin sensitivity test before equine rabies immune globulin application

Abstract

An epizootic outbreak of rabies occurred in 1995 in Ribeirão Preto, SP, with 58 cases of animal rabies (54 dogs, 3 cats and 1 bat) confirmed by the Pasteur Institute of São Paulo, and one human death. The need to provide care to a large number of people for the application of equine rabies immune globulin (ERIG) prevented the execution of the skin sensitivity test (SST) and often also the execution of desensitization, procedures routinely used up to that time at the Emergency Unit of the University Hospital of the Faculty of Medicine of Ribeirão Preto, University of São Paulo (EU-UHFMRP-USP), a reference hospital for the application of heterologous sera. In view of our positive experience of several years with the abolition of SST and of the use of premedication before the application of antivenom sera, we used a similar schedule for ERIG application. Of the 1489 victims of animal bites, 1054 (71%) received ERIG; no patient was submitted to SST and all received intravenously anti-histamines (anti-H1 + anti-H2) and corticosteroids before the procedure. The patients were kept under observation for 60 to 180 minutes and no adverse reaction was observed. On the basis of these results, since December 1995 ERIG application has been decentralized in Ribeirão Preto and has become the responsibility of the Emergency Unit of the University Hospital and the Central Basic Health Unit, where the same routine is used. Since then, 4216 patients have received ERIG (1818 at the Basic Health Unit and 2398 at the EU-UHFMRP), with no problems. The ideal would be the routine use of human rabies immune globulin (HRIG) in public health programs, but this is problematic, because of their high cost. However, while this does not occur, the use of SST is no longer justified at the time of application of ERIG, in view of the clinical evidence of low predictive value and low sensitivity of SST involving the application of heterologous sera. It is very important to point out that a negative SST result may lead the health team to a feeling of false safety that no adverse reaction will occur, but this is not true for the anaphylactoid reactions. The decision to use premedication, which is based on knowledge about anaphylaxis and on the pharmacology of the medication used, is left to the judgment of health professionals, who should always be prepared for eventual untoward events.

Serum Sickness after Equine Rabies Immunoglobulin in Identical Male Twins: Two Case Reports

“…We would suggest human rabies immunoglobulin for them, instead of ERIG, because of the lower incidence of serum sickness and other side effects [5, 6]. Owning to the skin sensitivity test results which were negative in our cases, our findings confirm previous studies which have reported that this conventional test had poor predictability of anaphylaxis or serum sickness reactions [15]. Thus, monitoring of acute and delayed adverse reactions is essential regardless of types of immunoglobulins.…”

Monoclonal antibodies for the prevention of rabies: theory and clinical practice

“…33 Medical concerns may be managed by performing skin tests or by premedication with antihistamine and corticosteroids. 34,35 Compared with HRIG, the less expensive nature of ERIG seems to be the primary reason for its continued use in developing countries. All licensed RIGs are expected to neutralize all known RABV variants, but no available product will neutralize all described lyssaviruses.…”

Intravenous administration of equine-derived whole IgG antivenom does not induce early adverse reactions in non-envenomed horses and cows

“…Hypersensitivity skin test is used to predict possible IgE-mediated anaphylactic reactions induced by a variety of medicines. However, since anaphylactoid reactions to antivenoms are not mediated by IgE, snake antivenom skin test has been of low value in predicting these reactions [9,29], and it is therefore not routinely recommended in the clinical administration of antivenoms [30,31]. Thus, intradermal skin test in antivenom administration is only valid for the prediction of type I hypersensitivity, i.e.…”