Cutaneous reaction or necrosis in response to interferon alpha: can interferon be reintroduced after healing? Six case reports.

Purpose. - Alpha, beta or gamma interferon (INF) are cytokines produced by cells in response to antigenic stimulation. They are used to treat various hepatic, hematological, oncological and neurological diseases. Cutaneous re actions (rash, alopecia, labial herpes, erythema, or induration at the site of injection, and more rarely cutaneous necrosis) represent 5 to 12% of si de-effects observed in patients receiving INF: The authors report six cases of local cutaneous reactions to alpha INF; five of which corresponded to c utaneous necrosis. This makes them question the relevance of INF reintroduc tion. Methods. - The study included 5 male and 1 female patients (mean age : 59.1 years; range : 42 to 74 years old). Three patients had chronic hepatitis C , while three others presented a blood disease. Results. - Cutaneous necrosis occurred after 1 to 10 months of treatment. T he mean time to healing was 16,2 weeks. Reintroduction of the drug includin g injection in other sites did not lead to recurrence of necrosis in five o ut of the six cases. Conclusion. - INF-induced cutaneous necrosis does not depend on the type of INF, the site of injection, the dose and may occur 2 months to 9 years aft er treatment implementation. The exact mechanisms involved in cutaneous nec rosis remain unknown. Morbidity is due to a very long time to healing (4 to 6 months). Futhermore, healing sometimes requires prior surgery. Physician s should be aware of the potential occurrence of erythema in patients treat ed by INF, as if is the first sign of necrosis. The site of injection shoul d then be modified. In case of necrosis, risk factors for thrombophilia, fa ctors reducing microcirculation (DHE, beta-blockers, cigarette smoking) sho uld be investigated. INF injections should be cautiously reintroduced in ot her sites with the help of a nurse in case of self-injections prior to the occurrence of necrosis. Regarding self-injections patients' training should be emphasized. (C) 2000 Editions scientifiques et medicales Elsevier SAS.