dear user melanin deficiency is due to an autoimmune disease..... It is also caused by genetic disorders and treatment may take years .......as the patches are on feet,hands,fingers and lips. It is found that the acral variety is more resistant to treatment. Still, you should not loose patience with treatment traeatment course may take few years....... Trimethoxsalen tablets and cream or lotion on skin.....it is preferrly also to give her sun rays for few min daily after application of lotion treatment........ ..... Cotinue treatment under observation of dermatologist...and please be patient with treatment course for few years also topical medication known as Monobenzone over the pigmented areas of skin and it will help in depigmenting those areas too and gradually ...... hope that helps you