Efficacy and safety of indigo naturalis ointment in Treating Atopic Dermatitis: A randomized clinical trial

Indigo naturalis, a herbal medicine with a history of use dating back to ancient times, may be a good alternative topical treatment for atopic dermatitis (AD). To provide empirical evidence of the efficacy and safety of Indigo naturalis ointment in treating AD. In this randomized double-blind clinical trial, participants aged 6 to 65 years with AD affecting less than 40% of their body surface area (BSA) and an Investigator's Global Assessment (IGA) score of 2 to 4 were randomized (2:1) to receive either Lindioil ointment or a vehicle ointment twice daily for 6 weeks. The primary endpoint was the percentage change in the Eczema Area Severity Index (EASI) from baseline to week 6. Secondary endpoints were as follows: EASI improvement ≥50%, 75%, and 90%; IGA score; BSA affected by AD; pruritus severity; and Dermatology Life Quality Index. The safety assessment included adverse events (AEs), laboratory tests, and physical examinations. The Lindioil group (32 participants) and vehicle group (16 participants) achieved mean percentage EASI reductions of 49.9% ± 36.5% (95% CI 36.8%–63.1%) and 19.6% ± 52.2% (95% CI -8.2%–47.4%), respectively (P = 0.0235). The Lindioil group also showed greater improvement in every secondary assessment category. No significant AEs occurred. Indigo naturalis ointment is effective for treating mild to severe AD topically, and appears to be safe. This is the first clinical trial to provide evidence supporting topical indigo-based AD treatment. ClinicalTrials.gov identifier: NCT02669888.