Only a few clinical trials have been published on the topical treatment of atopic dermatitis with herbal ointments. An ointment containing extracts from Mahonia aquifolium, Viola tricolor and Centella asiatica has previously been studied in open uncontrolled trials with children. However, no data exist on adult patients in a randomized controlled trial.
A total of 88 patients with mild-to-moderate atopic dermatitis were enrolled in a double-blind, vehicle-controlled, randomized, half-side comparison. Patients between 18 and 65 years of age were treated for 4 weeks with an ointment containing Mahonia aquifolium, Viola tricolor and Centella asiatica. The primary endpoint was a summary score for erythema, edema/papulation, oozing/crust, excoriation and lichenification according to a 4-point scale. Secondary efficacy variables were assessment of pruritus severity (10 cm VAS) and a global assessment of effectiveness as well as tolerability.
The study ointment reduced the primary and secondary endpoints slightly more than the base cream which was used as vehicle; the differences were not statistically significant. Since the climatic conditions during the study duration varied from very mild and sunny to very cold and dry, a post-hoc subanalysis was performed with a subset of 64 patients whose treatment was at a mean outside temperature of 10 degrees C or less. Under these conditions the primary endpoint showed high statistical significance.
In this trial, an ointment containing Mahonia aquifolium, Viola tricolor and Centella asiatica could not be proven to be superior to a base cream for patients with mild-to-moderate atopic dermatitis. However, a subanalysis indicated that the cream might be effective under conditions of cold and dry weather.