(CNN) -- When Yuki Izumoto developed ugly white patches on her neck, hands and face nearly a year ago, her dermatologist had no answers for her.
The 44-year-old Japanese housewife was embarrassed to show people her dotted hands, and the spots weren't going away.
Her doctor told her "it was a kind of disease, but the cause is unknown," she says.
Now it seems likely that she and thousands of others may have developed white blotches on their skin as a result of a popular whitening product from Japanese cosmetics brand Kanebo.
Izumoto says she used the product for several years.
Reports of such symptoms from thousands of customers have led Kanebo to initiate a voluntary recall of all of its products that contain the "quasi-drug ingredient" known as Rhododenol. In a statement, Kanebo said 6808 customers had complained of vitiligo -- the appearance of irregular white blotches, or inconsistent de-pigmentation of the skin -- as of July 19.
Kanebo advises customers to stop using the skin products in question immediately and to contact a dermatologist.
The company has set up a task force with "the mission of taking full responsibility for the care of all customers who experience vitiligo-like symptoms following the use of the affected products, through to the stage of full recovery."
Skin whitening is a near obsession for some women in many Asia countries, with both local and Western brands selling a variety of products designed to evenly lighten skin tone.
Kanebo has sold nearly five million products containing the recalled ingredient across 11 Asian countries, including Japan, Hong Kong and South Korea. There have been very limited sales in the United Kingdom. The company plans to visit all customers who have complained of skin blotches.
Meanwhile, Izumoto says she has yet to receive a visit and is angry at the company for not being in touch sooner.
"I used the products to become beautiful, but I was tainted by it," she says. She believes her skin may never return to normal.
Saori Ibuki contributed to this report.