How long should one wait to observe in case vitiligo spreads to other parts of body of a person who has vitiligo?
What does vitiligo look like?
Will the depigmented patches spread?
How is vitiligo diagnosed?

How long should one wait to observe in case vitiligo spreads to other parts of body of a person who has vitiligo?
At least one year.

One medical doctor recommended partial thickness skin grafting to treat vitiligo.

What does vitiligo look like?
Vitiligo is a condition in which white patches develop on the skin. Any location on the body can be affected, and most people with vitiligo have white patches in many areas of the body.

Melanin is the pigment that gives the skin its characteristic color. Vitiligo is caused by a loss of pigment in the skin, due to destruction of pigment-forming cells known as melanocytes. Although vitiligo affects all races equally, it is more noticeable in dark-skinned people. Vitiligo can cause cosmetic problems.

Vitiligo affects 1-2% of the American population, and it is estimated that 2 to 4 million Americans have the condition. In most cases, vitiligo develops early in life, between the ages of 10 and 30 years. Ninety-five percent of those affected will develop the disorder before age 40. Both men and women are equally likely to develop vitiligo. Vitiligo may run in families; those with a family history of vitiligo or premature graying of the hair are at increased risk for the development of vitiligo. Other risk factors that increase one's chances of developing vitiligo include having autoimmune diseases, such as autoimmune thyroid disease (Hashimoto's thyroiditis).

Vitiligo symptoms include an often rapid pigment loss in several areas of the skin. The initial appearance of the white patches can be followed by a stable period without any progression of the condition.

Will the depigmented patches spread?
Focal pattern vitiligo and segmental vitiligo remain localized to one part of the body and do not spread. There is no way to predict if generalized vitiligo will spread. For some people, the depigmented patches do not spread. The disorder is usually progressive, however, and over time the white patches will spread to other areas of the body. For some people, vitiligo spreads slowly, over many years. For other people, spreading occurs rapidly. Some people have reported additional depigmentation following periods of physical or emotional stress.

How is vitiligo diagnosed?
The diagnosis of vitiligo is made based on a physical examination, medical history, and laboratory tests.

A doctor will likely suspect vitiligo if you report (or the physical examination reveals) white patches of skin on the body-particularly on sun-exposed areas, including the hands, feet, arms, face, and lips. If vitiligo is suspected, the doctor will ask about your medical history. Important factors in the diagnosis include a family history of vitiligo; a rash, sunburn, or other skin trauma that occurred at the site of vitiligo 2 to 3 months before depigmentation started; stress or physical illness; and premature graying of the hair (before age 35). In addition, the doctor will ask whether you or anyone in your family has had any autoimmune diseases and whether you are very sensitive to the sun.

To help confirm the diagnosis, the doctor may take a small sample (biopsy) of the affected skin to examine under a microscope. In vitiligo, the skin sample will usually show a complete absence of pigment-producing melanocytes. On the other hand, the presence of inflamed cells in the sample may suggest that another condition is responsible for the loss of pigmentation.

Because vitiligo may be associated with pernicious anemia (a condition in which an insufficient amount of vitamin B12 is absorbed from the gastrointestinal tract) or hyperthyroidism (an overactive thyroid gland), the doctor may also take a blood sample to check the blood-cell count and thyroid function. For some patients, the doctor may recommend an eye examination to check for uveitis (inflammation of part of the eye), which sometimes occurs with vitiligo. A blood test to look for the presence of antinuclear antibodies (a type of autoantibody) may also be done. This test helps determine if the patient has another autoimmune disease.