The study was conducted between October 2006 and September 2007. The researchers recruited patients with chronic plaque psoriasis from the Division of Dermatology at Srinagarind Hospital at Khon Kaen University in Khon Kaen, Thailand. The patients were 18 years or older and had clinically diagnosed psoriasis covering more than 10% of the body surface. During a 4-week wash-out period, the patients did not use topical or systemic psoriasis treatments. The patients were randomized using a simple random number table to receive either an aloe cream containing 70% aloe mucilage (n=37) or the 0.1% TA cream (n=38). Both creams were prepared by the Faculty of Pharmaceutical Sciences at Khon Kaen University (Khon Kaen, Thailand). The patients applied the creams twice daily for 8 weeks. The researchers measured the severity of disease on a scale of 0-72 with the Psoriasis Area Severity Index (PASI). The change in PASI scores after 8 weeks of treatment was the primary outcome measure. The researchers considered a reduction of 75% or more a "marked" response, a reduction of 50-74% a "moderate" response, and a reduction of less than 50% a "slight" response. The patients completed the Dermatology Life Quality Index (DLQI) to measure their quality of life.

There were 80 patients at baseline, and 3 in the aloe group and 2 in the TA group were lost to follow-up. There were no significant differences between the groups in baseline DLQI or PASI scores. None of the patients experienced a complete recovery after 8 weeks of treatment. In the aloe group, 6 patients (16.2%) experienced a marked response, while 4 patients (10.5%) in the TA group did so. In the aloe group, 20 patients (54.1%) experienced a moderate response to treatment, while 25 patients (65.8%) in the TA group had a moderate response. The researchers found that 10 patients (27%) in the aloe group and 9 patients (23.7%) in the TA group had a slight response to treatment. In the aloe group, 1 patient showed no response to treatment. After 8 weeks, the average change in PASI scores was significantly greater in the aloe group, when compared to the TA group (P=0.0237); however, the average PASI scores were not significantly different between the groups. There were no statistically significant changes in DLQI scores after 8 weeks of treatment, although both groups experienced decreases. The authors report that no serious adverse events occurred during the study, but 6 patients in the aloe group experienced stinging and itching at the plaques during the first week.

The authors propose that aloe's anti-inflammatory effects may be responsible for the effects observed in this study. They conclude that aloe cream "can be considered a safe, alternative treatment for mild to moderate chronic plaque psoriasis." More research is needed to confirm the results of this study. 

—Marissa Oppel-Sutter, MS