1. What is vitiligo
Vitiligo is a recalcitrant skin disease characterized by the loss of pigment in the cutaneous tissue. It is caused by many pathogenic factors (chemicals and heavy metal toxic substances), or psychological trauma. These adverse factors cause the endocrine and immunological disturbances resulting in damage and loss of melanocytes, thus the vitiliginous patches (skin lesions).In traditional Chinese medicine vitiligo is called by many names: baidian, baishi, or baibofeng.

2. The initiation and development process of the skin lesions
The disease starts as a localized white spot or patch in certain areas on the surface of the skin. In a small number of patients this can start in deeper tissue, such as the uvea -- the pigmented epithelia within the eye. The lesion manifests as grain-sized or nail-sized patches. It can be singular or multiple in number occurring in many parts of the body simultaneously. Most patients have no subjective symptoms and they are unaware of any causative factors. The white patches are discovered in many cases only by accident. A portion of the patients start to feel itchy in the area before the vitiliginous skin lesion gradually develops. In yet another proportion of patients the predisposing factors are quite apparent, such as allergy to drugs and cosmetics, strong sunlight exposure after sightseeing or sea-side bathing, after trauma and infections. Most of the skin lesions (white, depigmented patches) progress slowly, with gradual enlargement of the small, primary lesion, and new lesions may continue to appear in other parts of the body. A minority of patients may experience a rapid spreading of the lesions to virtually every part of the body in a short period of time, forming large disseminated patches. In childhood patients these rapid spreading type is often related to long-term intake of contaminated foods or dietary bias while in adult patients the rapid spread is related to psychological trauma and mental stress. In some patients the lesions may remain in the initial sites without further spreading. This is the stable type. In some patients the initial lesions are stable but inappropriate treatment causes the rapid deterioration. There is also a special type of lesions seen in children. Congenital hypopigmented patch or patches of pale white color is seen in certain areas of the body after birth. Such patches may slightly increase with age, and is not diagnosed as vitiligo. However in recent years it was found that these patches may develop into vitiligo. The characteristics is that the color of the patches change from pale white to pure white and the patches spread to other parts of the body after initial local enlargement. In such cases a diagnosis of vitiligo can be made and the patients treated promptly.

3. Changes in color of skin lesions
At the start the white skin lesions are usually inconspicuous, of pale white color. As the disease progresses, the white patches become more apparent to become pure white in color. In the more advanced stage the hair and the vellous hair also turn white, with the falling of vellous hair in more severe cases and closure of the openings of the sweat gland ducts. Therefore there will not be any sweating in these diseased skin due to the occlusion of these openings. In this stage there is complete depletion of melanocytes in the diseased areas and the treatment is very difficult.