What is an intralesional steroid injection?
An intralesional injection is the direct injection of a steroid into a lesion or into the skin. The aim of an intralesional injection is to deliver a high concentration of medicine into the site of the pathology to maximise efficacy while minimising systemic adverse effects of the drug.
What drugs are used for intralesional steroid injection and why?
The most common steroid used for intralesional injection is triamcinolone acetonide.
What are the indications for intralesional steroid injection?
Intralesional steroid is used for localised inflammatory, hyperplastic, and hypertrophic lesions like cystic acne, keloid and hypertrophic scar.
It is also useful for immunological disorders such as:
Discoid lupus erythematosus
Lichenified skin disorders such as:
Lichen simplex chronicus
Hypertrophic lichen planus.
Granulomatous skin disorders such as:
Medications, dosage and method of intralesional injection
Triamcinolone acetonide with 10 mg/mL or 40 mg/mL strengths are used for intralesional steroid injection. The dose depends on the type, size, and location of the lesion.
The steroid can be diluted with normal saline or plain local anaesthesic.
What is the duration between each injection?
For cystic acne, usually one injection would be sufficient. For hypertropic scar and keloid, the procedure can be repeated every 4–6 weeks until the scar become flatten.
What are the potential side effects and risks of an intralesional injection?
The possible side effects of intralesional injection of a corticosteroid are:
Short-term local pain, inflammatory reaction, and rarely, infection.
Longer-term hypopigmentation, hyperpigmentation, atrophy (more likely in the case of subcutaneous injection) and telangiectasia.
Is the procedure painful?
The injection is slightly painful, numbing cream may be used to reduce the pain. Doctor may also mix the steroid with topical anaesthetic to reduce discomfort.