Nov. 17, 2008 -- Psoriasis patients showed dramatic improvement after 12 weeks of treatment with an ointment containing indigo naturalis, a Chinese herbal remedy.
The findings come from a study by Yin-Ku Lin, MD, of Chang Gung Memorial Hospital in Taipei, Taiwan, and colleagues. For more than five years, the researchers have been using the indigo ointment to treat psoriasis patients who do not respond to standard Western drug therapy.
"We anticipate that indigo naturalis ointment can be an alternative or complementary therapy for psoriasis and believe it will be a great benefit to this patient population," Lin and colleagues suggest.
Indigo naturalis is a traditional Chinese medicine derived from the plant Strobilanthes formosanus Moore. It's typically taken orally, but long-term use has been linked to stomach and liver problems. So Lin's team mixed the indigo powder with a base made of petroleum jelly, yellow wax, and olive oil.
In their study, the researchers gave the indigo ointment to 42 patients whose chronic plaque psoriasis did not improve despite at least two different medical treatments.
All of the patients had bilateral psoriasis -- that is, they had equally severe psoriasis plaques on both sides of their body. The patients spread the indigo ointment on the plaques on one side of the body and the base alone on plaques on the other side of the body.
The dark indigo powder stained the patients' skin but came off after washing. Before regular checkups, the patients washed all the ointment away so that their doctors would not know which side of the body had received the real treatment and which received the base alone.
The soothing ointment base, all by itself, did offer a bit of relief. But the indigo ointment worked much better. After 12 weeks of indigo treatment, 31 of the 42 patients' psoriasis plaques cleared or nearly cleared.
No harmful side effects were seen, although patients were not happy that the ointment stained their skin and clothing, even though it washed off and there was no permanent change in skin color. Also, the ointment has a disagreeable odor. Lin and colleagues suggest that researchers should look for a more potent, more convenient form of indigo ointment than their "crude herb" ointment.
"Indigo naturalis ointment treatment has neither adverse effects, such as those found with corticosteroid treatment, or other toxic effects based on our past five years of clinical observation. Furthermore, it costs much less," Lin and colleagues note.
The researchers report their findings in the November issue of Archives of Dermatology.