Intralesional injection is the direct injection of a therapeutic substance into a lesion or into the skin. The purpose is to deliver a medicine directly into the site to maximise efficacy while minimising systemic adverse effects of the drug.

Examples of Intralesional injections are:

• Intralesional injection of corticosteroids, bleomycin or 5-FU into keloid scars.
• injection of corticosteroids into scalp for alopecia areata.
• Injections of botulin toxin into the armpits to temporarily block the sweat glands for the treatment of axillar hyperhidrosis.
• injections of botulin toxin in facial musles for treatment of migraine of for bruxism.
• Injections of hyaluronic acid into scars to fill the depression of deep scars or to loosen adherences and tethering in acne scars.