What is the procedure for a triamcinolone (corticosteroid) intralesion acne injection in a young individual with a 2-month history of a resistant pimple?

Intralesional Triamcinolone Injection Procedure for Resistant Acne

For a resistant acne nodule or cyst, inject triamcinolone acetonide at 2.5-5 mg/mL concentration using a 30-gauge needle, delivering 0.05 mL into the center of the lesion just beneath the dermis, which will produce visible flattening within 48-72 hours. 1, 2

Pre-Procedure Preparation

• Cleanse the skin thoroughly with an antiseptic solution to minimize infection risk 1
• Topical anesthesia is optional for this brief procedure, though some practitioners apply it for 30 minutes if treating multiple lesions 3
• Counsel the patient about potential adverse effects including temporary atrophy and hypopigmentation before every injection 2

Medication Preparation

• Use triamcinolone acetonide 10 mg/mL diluted with sterile normal saline to achieve a final concentration of 2.5-5 mg/mL 1, 2
• The most commonly used concentration among dermatologists is 2.5 mg/mL (reported by 52.5% of practitioners), which minimizes complications while maintaining efficacy 2
• Lower concentrations reduce the risk of atrophy and hypopigmentation compared to higher concentrations 1, 4

Injection Technique

• Select a 30-gauge, 4 mm needle with the bevel facing upward 3, 1
• Inject into the center of the lesion (61.6% of dermatologists use this approach) at the intradermal to upper subcutaneous level 2
• Deliver 0.05 mL per injection site (the most frequently used volume by 42.3% of practitioners) 2
• Formation of a visible papule with blanching confirms proper intradermal placement and ensures the medication stays within the target tissue rather than entering deeper vasculature 3
• Avoid high injection pressures or volumes, particularly in periocular areas, as rare cases of central retinal artery embolization have occurred with upper eyelid injections 3

Post-Procedure Instructions

• Advise patients to avoid direct sunlight and heavily scented facial products for 24 hours following the procedure 3
• Expect visible improvement within 48-72 hours, with most nodules flattening significantly in this timeframe 1
• Schedule follow-up at one week to assess response and determine if additional treatment is needed 5

Critical Limitations and Contraindications

• This technique is reserved for individual stubborn lesions only, not for patients with multiple active nodules who require systemic therapy 1
• Do not inject at sites of active infection or in patients with previous hypersensitivity to triamcinolone 1
• Avoid large-volume injections in patients with active tuberculosis or systemic fungal infections 1
• Consider isotretinoin as definitive therapy for patients with severe nodular acne, significant psychosocial burden, or scarring risk, as it achieves 90% lesion reduction in 81% of patients at 20 weeks 1

Adverse Effects and Management

• Local atrophy occurs in less than 1% of patients but can last over 6 months when it develops (reported by 48.4% of practitioners who observed it) 2
• Hypopigmentation and pigmentary changes are possible, particularly with higher concentrations or repeated injections 1, 6
• Branch-shaped or linear patterns of atrophy and hypopigmentation can occur if the medication tracks along tissue planes 6
• Granulomatous foreign body reactions to triamcinolone have been rarely reported 7
• Using the lowest effective concentration (2.5 mg/mL) and smallest volume (0.05 mL) significantly reduces these risks 1, 2

Enhanced Efficacy Option

• Adding intralesional lincomycin (75 mg/mL) to triamcinolone achieved 100% improvement at one week in all patients compared to 70% with triamcinolone alone, though this combination is not widely adopted in current practice 5