Intralesional interferon gamma treatment for keloids and hypertrophic scars.

Keloids and hypertrophic scars are characterized by excessive collagen formation. Interferon gamma is a lymphokine that can down-regulate collagen synthesis in vitro and in vivo and, therefore, has potential therapeutic benefit in the management of abnormal scars. Intralesional scar injections of interferon gamma were performed to determine the tolerance toxicity and to obtain preliminary evidence for the efficacy of this treatment in the management of hypertropic and keloid lesions. All scars decreased in linear dimensions and flattened out. Five of 10 scars studied decreased at least 50% in linear dimensions. Interferon gamma can safely be administered intralesionally once per week up to a dosage of 0.05 mg for 10 weeks with no serious toxic effects. The commonest reported side effect was a mild headache.