intralesional steroids for keloid and hypertrophic scarring

Last reviewed 01/2018

Intralesional coritocsteroids are a mainstay in the treatment of hypertrophic and keloid scars. Their molecular action is mannifold:

• reduced glycosaminoglycan synthesis
• decreased collagen deposition
• reduced fibroblast activity
• decreased pro-inflammatory cytokine production

Intralesional injection may be combined with other treatment modalities. For example, after scar excision and before wound closure, the surrounding dermis may be injected with steroid. More typically, an active hypertrophic or keloid scar is injected with an agent like triamcinalone every four to six weeks. Concentrations of 10-40 mg/ml are injected with a 25- to 27-gauge needle. Maximal doses at one consultation can be up to 100mg. 0.5 ml or 1ml diabetic syringes are well suited for this task as the integrated needle permits adequate pressure to be generated; there is often great resistance to steroid infiltration due to the density of the scar. Injection can be painful and as such, a useful technique is to mix the corticosteroid with local anaesthetic, to inject local anaesthetic into the subcutaneous tissue prior to infiltration, or to apply local anaesthetic cream to the area for an adequate duration (typically 30 minutes to one hour) prior to steroid injection. At injection, the needle must be sited sufficiently deeply within the lesion to limit the tendency to ulceration. Adequate infiltration is indicated by transient blanching of the lesion.

Most lesions respond to this regimen with flattening, reduction in erythema and pruritus. This change may take some weeks before starting. Anecdotally, hypertrophic scars are thought to respond better than keloid scars. For the latter, up to half of all lesions recur.