Vitiligo is a relatively common clinical skin disease, people will have white patches on the damaged skin after suffering from vitiligo. How to diagnose vitiligo, including skin color, skin changes after sun exposure, etc., as follows: 1, After sunlight skin changes: if vitiligo sunlight after, the white spot will be red and itchy, if not vitiligo, after sunlight will not have a significant change. So vitiligo this disease appears harmful, if not able to correctly diagnose, when the body appears the symptoms of white spots, or suggest timely to the regular hospital, for comprehensive diagnosis and treatment, so as not to delay the disease.