Cutaneous delayed hypersensitivity reactions to heparins and heparinoids.

Introduction. Due to cross-reactions between unfractionated heparins, low-m olecular-weight heparins and sometimes heparinoids, cutaneous delayed hyper sensitivity reactions might be a problem for the choice of therapeutic alte rnative. We report on two cases of sensitization to heparins and heparinoid s. Observations. One woman developed localized skin reaction to a low-molecula r-weight heparin, then a generalized maculopapular rash when an intravenous injection of unfractionated heparins was performed, The second patient had a localized then extended reaction to a low-molecula r-weight heparin and was referred for the choice of a well tolerated method to obtain anticoagulation during a pulmonary surgery. Methods, Patch tests , prick tests, intradermal and subcutaneous tests were performed with sever al unfractionated heparins, low-molecular-weight heparins, danaparoid and l epirudin in both cases. Results. In the first case, tests performed with both heparins and heparino id were positive and the use of lepirudin was proposed if anticoagulation w as necessary. In the second case the subcutaneous danaparoid injection indu ced a localized reaction on the injection site. Danaparoid injections were continued associated with localized applications of dermocorticoids without any side effect. Discussion, Cutaneous delayed hypersensitivity reactions occur on the injec tion site but can also be generalised. Cross reactions might be unexpected therefore skin-tests are necessary to guide the choice of a therapeutic alt ernative. In case of intolerance to both heparins and heparinoids various s olutions may be proposed such as the application of topical corticosteroids on the injection site or the administration of hirudins. There is no cross sensitization between heparins and hirudins, but the use of hirudins is re stricted and requires specific monitoring.