Interferon alpha-2a has already been shown to be effective in clinical use of virus-originated diseases such as hairy cell leukemia, condyloma acuminatum, and AIDS-related Kaposi's sarcoma. The use of recombinant alpha-interferon may allow common warts to be treated relatively atraumatically and with less incidence of recurrence.

We tried to determine the safety and effectiveness of intralesional injections of recombinant alpha-2a interferon in the treatment of patients with common warts.

A single wart on each patient was weekly injected with 0.75 to 1.5×10⁵ IU/25mm² of interferon for 8 weeks, and the response to treatment was followed up-to 6 months.

Clearing of the treated wart at the end of treatment occurred in 5(71%) out of 7 patients and the rest showed no improvement. With evaluation for relapses up-to 6 months after treatment, warts relapsed in 2(40%) out of 5 patients. Therefore, 3(43%) out of 7 patients were completely free of warts 6 months after treatment.

Intralesional recombinant interferon alpha-2a has a limited therapeutic effect, but may be considered as a therapeutic modality of recalcitrant verruca or when it can be anticipated that destructive techniques or blistering agents will not be tolerated.