[Cutaneous reactions or necrosis from interferon alpha: can interferon be reintroduced after healing? Six case...

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 reactions (rash, alopecia, labial herpes, erythema, or induration at the site of injection, and more rarely cutaneous necrosis) represent 5 to 12% of side-effects observed in patients receiving INF. The authors report six cases of local cutaneous reactions to alpha INF, five of which corresponded to cutaneous necrosis. This makes them question the relevance of INF reintroduction.

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.

Cutaneous necrosis occurred after 1 to 10 months of treatment. The mean time to healing was 16.2 weeks. Reintroduction of the drug including injection in other sites did not lead to recurrence of necrosis in five out of the six cases.

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 after treatment implementation. The exact mechanisms involved in cutaneous necrosis remain unknown. Morbidity is due to a very long time to healing (4 to 6 months). Futhermore, healing sometimes requires prior surgery. Physicians should be aware of the potential occurrence of erythema in patients treated by INF, as it is the first sign of necrosis. The site of injection should then be modified. In case of necrosis, risk factors for thrombophilia, factors reducing microcirculation (DHE, beta-blockers, cigarette smoking) should be investigated. INF injections should be cautiously reintroduced in other 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.