Vitiligo usually starts with the development of small lesions or depigmented patches which often shows a variable number of depigmented hair and without any change in the skin texture in specific areas of the body. These patches are usually observed in areas that are normally relatively hyperpigmented. The progression of this disease highly varies and depends on the type of vitiligo you have.

The disease may start at any stage. Onset as early as birth and as late as 81 years of age has been reported. Most cases with vitiligo vulgaris type begin in 2nd to 4th decades of life. 

Vitiligo is usually divided into two categories: localized and generalized. Localized vitiligo refers to the depigmentation that is exclusive to a specific part of the body, while generalized vitiligo has the ability to spread and affect multiple skin regions. 
Localized vitiligo further divided into Focal(small isolated lesion in one area of the body), segmental (white patches only occur on one side of the body) and Mucosal Generalized vitiligo further divided into Acrofacial (involving  face and extremities), Vitiligo Vulgaris (scattered distribution throughout the body), vitiligo Universalis (a wide distribution which eventually leads to complete depigmentation)

Vitiligo is a multifactorial disorder related to both genetic and non-genetic factors. Trigger events like stress, sunburn, mechanical trauma, chemical exposure cause an autoimmune response in a genetically susceptible individual which target melanin pigment-producing cell-melanocytes, predisposing individual to develop vitiligo.

Vitiligo occasionally goes away by itself, but a cure cannot be guaranteed.Some medical and surgical treatments may slow its progression for which you should consult with a skilled dermatologist.

No, Vitiligo is not contagious in any way. It does not spread by contact or touching, sharing foods or clothes. Vitiligo seems to be the result of a combination of genetic, biochemical, immunologic and neurogenic factors.

No. There is no risk of skin cancer from vitiligo. Although people with Vitiligo are prone to sunburn; and sunburn increases the risk of cancer. Hence, take appropriate precautions to prevent sunburn by applying sunscreen lotions. 

Studies suggest that heredity can influence the susceptibility of an individual to contract vitiligo, with the skin condition commonly occurring in more than one case in a family. But although the genetic predisposition of a person to vitiligo obviously affects its development, there are also various external factors that can lead to this skin condition.

In rare cases, vitiligo patches can itch because of the increased sensitivity. Itching can also be felt in regions where the depigmentation is starting. But to ensure an accurate diagnosis, seek an expert dermatologist's advice to make sure that you are not affected by another skin condition.

Although most vitiligo patients are otherwise healthy, generalized vitiligo is epidemiologically associated with a number of other autoimmune diseases, especially in patients with a family history of vitiligo or other forms of autoimmunity. The associated conditions include autoimmune thyroid disease, pernicious anemia, addison's disease, lupus erythematosus, rheumatoid arthritis, and adult-onset autoimmune diabetes mellitus.

Studies have shown that people with vitiligo are often deficient in certain vitamins, like vitamin D, folic acid, B12, copper, and zinc. These, along with others like CoQ10, vitamin E, sometimes vitamin C and a high-quality multi-vitamin are prescribed to help stabilize the immune system. Vitamins/supplements are generally used in combination with other treatments.

Different treatment modalities are available to stop Vitiligo from spreading, which depends on the extent, location and activity of disease as well as the patient's age, skin type, and motivation to undergo treatment for which take the advice of a skilled dermatologist. 

Existing treatments include topical and systemic immunosuppressants, phototherapy, and surgical techniques, which together may serve to halt disease progression, stabilize depigmented lesions, and encourage repigmentation. Also, wear sun safe clothing and sunscreen, avoid excessive stressful situations and improve nutrition and diet to prevent the spread of vitiligo.

Melanin is a natural pigment found in most organisms including humans. People with high amounts of melanin tend to have darker skin, whereas people with less melanin have lighter skin. Melanin acts as a physical barrier that scatters UV radiations and reduces the UV penetration through the epidermis and protects from UV induced damage like sun-induced skin cancer.
However, melanin can also have toxic properties, especially after exposure to UVR. At present, the clinical significance of deleterious effects in carcinogenesis is not known.