Intralesional therapy — SAQ

Stem

A 26-year-old woman has a firm, claw-like scar on the shoulder that grew beyond the original acne wound edges and is itchy and cosmetically distressing. Separately, she has two 2 cm round bald patches on the scalp with exclamation-mark hairs. She asks for “steroid injections.”

Questions

a) Name the most likely diagnoses for the shoulder and scalp lesions. (2 marks)

b) Explain the rationale for intralesional triamcinolone and how concentration differs by site. (3 marks)

^[3]c) Outline injection technique endpoints and a typical treatment interval. (3 marks)

d) List important local and rare systemic adverse effects to counsel. (2 marks)

Model answer

a) (2 marks) — Shoulder: keloid (grows beyond original wound). Scalp: patchy alopecia areata.^[1][2]

^[2]b) (3 marks) — IL TAC creates a local corticosteroid depot with high tissue levels in thick scar or peri-follicular dermis. Use lower working concentrations on scalp/face (atrophy-sensitive) and higher concentrations may be required for thick truncal keloid bulk; dilute stock 10 or 40 mg/mL thoughtfully and document.

^[1]c) (3 marks) — Small-gauge needle into scar midsubstance or dermal AA grid (~1 cm spacing); inject small aliquots to blanching; limit total session dose; repeat about every 3–6 weeks while monitoring response and atrophy. Keloids often need multimodal adjuncts if incomplete.

d) (2 marks) — Local: pain, atrophy, telangiectasia, hypopigmentation, ulceration if other agents used. Rare systemic: Cushingoid/HPA effects after large cumulative doses; rare anaphylaxis — emergency readiness.^[1][3]

References3ShowHide

1. [1]Yin Q, Wolkerstorfer A, Lapid O, et al. KECORT Study: an international e-Delphi study on the treatment of keloids using intralesional corticosteroids in clinical practice Am J Clin Dermatol, 2024.PMID 39298112
2. [2]Mateos-Haro M, Novoa-Candia M, Sánchez Vanegas G, et al. Treatments for alopecia areata: a network meta-analysis Cochrane Database Syst Rev, 2023.PMID 37870096
3. [3]Fredman R, Tenenhaus M. Cushing's syndrome after intralesional triamcinolone acetonide: a systematic review of the literature and multinational survey Burns, 2013.PMID 23092701