Cutaneous Ulcerations Following Subcutaneous Interferon β Injection to a Patient with Multiple Sclerosis

We report a case treated with interferon beta‐1b for multiple sclerosis (MS), who developed severe cutaneous ulcers after six months of therapy. Interferon beta‐1b had been used in a regimen of 8 million IU administered subcutaneously through oblique direction of the needle, twice a week. The cutaneous ulcers developed at inoculation sites, as a result of penetration of interferon beta into dermis. Other underlying diseases of coagulative or bleeding disorders or secondary infection were excluded. Histological features of non‐specific inflammatory reactions including hyperplastic changes of blood vessels without any evidence of vasculitis were the prominent features in this case. Corticosteroid and interferon beta‐1b therapy was continued on restricted sites on the extremities with care not to repeat injections at the same sites previously used. The administration of interferon beta into subcutaneous fatty tissues vertically reduced the incidence of dermal penetration of drug and occurrence of ulcerations in this patient. We review other case reports of severe cutaneous reactions associated with interferon beta‐1b therapy in MS patients and conclude that local cytokine‐mediated, adverse, immune reaction or non‐specific cutaneous inflammatory reaction to interferon beta‐1b initiated the skin ulceration long after institution of therapy at the injection sites, and the reaction might be related to the depth of injection.