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03-11-2011 | Psoriasis | Article

Indigo naturalis shows potential for treating nail psoriasis


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MedWire News: Results from a pilot study suggest that topical application of indigo naturalis ointment, extracted from the leaves of indigo-bearing plants such as Baphicacanthus cusia and Polygonum tinctorium, may improve the symptoms of nail psoriasis.

"Although preliminary, these results indicate that it could provide a novel therapeutic option for nail psoriasis, a disease notoriously difficult to treat," say Yin-Ku Lin (Chang Gung Memorial Hospital, Keelung, Taiwan) and colleagues.

They report that over the last 8 years they have treated more than 10,000 patients with skin psoriasis using topical indigo naturalis, resulting in significant symptom improvement. More recently patients with nail psoriasis were also treated successfully in the same manner.

The team explains that patient compliance to indigo naturalis treatment may be affected by the blue stains that it can leave on the nails.

In the current study, Lin and co-workers tested the efficacy of a refined formulation of indigo naturalis extract, designed to reduce blue discoloration of the skin, nails, and clothes, on the nails of 28 patients with nail psoriasis.

The participants applied one drop of the extract to the affected nails twice a day for 24 weeks. The researchers assessed efficacy of the extract using the Nail Psoriasis Severity Index (NAPSI), where higher scores indicate and a modified target NAPSI for the most severely affected nail.

Mean NAPSI score decreased significantly from 36.1 at baseline to 14.9 at week 24, indicating that application of indigo naturalis extract could be an effective treatment for this condition, the researchers note.

In addition, mean modified target NAPSI also decreased significantly from 11.7 at baseline to 3.6 at week 24.

"Further study is required to confirm safety and efficacy with a larger and more rigorously controlled trial, as well as to elucidate the pharmacological mechanisms of the observed antipsoriasis effects," write Lin et al in the journal Dermatology.

"If further trials are successful, indigo naturalis may become an important tool in the treatment of a notoriously difficult disease," they conclude.

MedWire ( is an independent clinical news service provided by Current Medicine Group, a trading division of Springer Healthcare Limited. © Springer Healthcare Ltd; 2010

By Helen Albert

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