How is vitiligo diagnosed?

If a doctor suspects that a person has vitiligo, he or she usually begins by asking the person about his or her medical history. Important factors in a person's medical history are a family history of vitiligo; a rash, sunburn, or other skin trauma 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 need to know whether the patient or anyone in the patient's family has had any autoimmune disorders and whether the patient is very sensitive to the sun.

The doctor will then examine the patient to rule out other medical problems. The doctor may take a small sample (biopsy) of the affected skin. He or she may also take a blood sample to check the blood-cell count and thyroid function. The doctor may examine your skin with a special black light called a Woods Light, which illuminates areas of vitiligo. This also helps the doctor rule out other conditions. For some patients, the doctor may recommend an eye examination to check for uveitis (inflammation of part of the eye). 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 any other autoimmune conditions.