Clinical assessment of patients with recalcitrant psoriasis in a randomized, observer-blind, vehicle-controlled trial...

To evaluate the efficacy and safety of treatment with indigo naturalis in patients with recalcitrant plaque-type psoriasis.

Randomized, observer-blind, vehicle-controlled, intrapatient comparison study.

Ambulatory department of a hospital.

Forty-two outpatients with chronic plaque psoriasis were enrolled in the study from May 1, 2004, to April 30, 2005.

The patients applied either indigo naturalis ointment or vehicle ointment topically to each of 2 bilaterally symmetrical psoriatic plaque lesions for 12 weeks (depending on the date of enrollment in the study).

The outcomes were assessed using the following criteria: the sum of erythema, scaling, and induration scores and the clearing percentage of the target plaque lesion assessed by 2 blinded observers.

Significant reductions in the sum of scaling, erythema, and induration scores (P < .001) (mean score, 6.3 after indigo naturalis treatment vs 12.8 in control subjects) and plaque area percentage (P < .001) (mean percentage, 38.5% after indigo naturalis treatment vs 90% in controls) were achieved with topical application of indigo naturalis ointment. Approximately 31 of 42 patients (74%) experienced clearance or near clearance of their psoriasis in the indigo ointment-treated lesion.

Topical indigo naturalis ointment was a novel, safe, and effective therapy for plaque-type psoriasis.