What is the recommended concentration and administration protocol for triamcinolone acetonide (corticosteroid) for scalp intralesional injections in the treatment of alopecia areata?

Recommended Protocol for Triamcinolone Acetonide Intralesional Injections in Alopecia Areata

For scalp intralesional injections in alopecia areata, triamcinolone acetonide should be administered at a concentration of 5-10 mg/mL, with 0.05-0.1 mL injected per site just beneath the dermis in the upper subcutis, given monthly until satisfactory response is achieved. 1

Concentration and Dosing

• Concentration: 5-10 mg/mL triamcinolone acetonide 1
• Volume per site: 0.05-0.1 mL 1
• Injection depth: Just beneath the dermis in the upper subcutis 1
• Frequency: Monthly injections until satisfactory response 1

Recent evidence suggests that lower concentrations may be equally effective with fewer side effects. A 2020 study found that 5 mg/mL was equally effective compared to 10 mg/mL, with complete hair regrowth in 43.5% vs 53.8% of patients respectively (not statistically significant) 2. Another study in 2021 proposed a step-up regimen starting with 2.5 mg/mL and increasing based on response, as this approach balanced efficacy with reduced side effects 3.

Patient Selection

Intralesional corticosteroids are most appropriate for:

• Patchy hair loss of limited extent
• Fewer than five patches of < 3 cm in diameter
• Cosmetically sensitive sites
• Patients with less than 50% scalp involvement 1

Administration Technique

1. Inject directly into the affected areas
2. Multiple injections given as needed, limited by patient discomfort
3. Space injections approximately 1 cm apart 4
4. Alternative delivery methods such as needleless devices (Dermajet) can be used 1

Expected Response and Duration

• Effect typically lasts about 9 months 1
• Complete hair regrowth occurs in approximately 62% of patients with monthly injections 1
• Early response can be detected dermoscopically at 4 weeks with regrowth of new vellus hair 5
• Better response is observed in patients with:
  • Fewer patches
  • Smaller patch size
  • Presence of exclamation mark hairs
  • Disease duration less than 6 months 1, 2

Monitoring and Follow-up

• Assess response after 6-12 weeks of treatment 1
• Use dermoscopy to identify early signs of clinical response and adverse effects 5
• Monitor for side effects, particularly folliculitis and skin atrophy 1

Common Side Effects

• Skin atrophy at injection sites (more common with 10 mg/mL concentration) 1, 3
• Mild pain during injection 1
• Folliculitis (typically reversible) 1
• Telangiectasia (more common with higher concentrations) 3

Clinical Pearls and Pitfalls

1. Pitfall: Using high concentrations in all patients

   • Solution: Consider starting with lower concentrations (2.5-5 mg/mL) and increasing if needed, especially in patients with thin skin or risk factors for atrophy 3

2. Pitfall: Treating patients with poor prognostic factors using only intralesional steroids

   • Solution: Recognize poor prognostic factors (childhood onset, ophiasis pattern, extensive hair loss, long duration, associated nail changes) and consider additional or alternative treatments 1

3. Pitfall: Failure to recognize when to discontinue treatment

   • Solution: If no response is seen after 3 monthly injections, consider alternative approaches 4, 6

4. Pitfall: Overlooking psychological impact

   • Solution: Consider psychological support and referral to patient support groups 1

The evidence consistently supports intralesional triamcinolone acetonide as the most effective first-line treatment for localized alopecia areata, with superior results compared to topical treatments like tacrolimus 6.