Although the diagnosis of vitiligo generally is made on the basis of clinical findings, biopsy is occasionally helpful for differentiating vitiligo from other hypopigmentary disorders.
Vitiligo may be associated with other autoimmune diseases, especially thyroid disease and diabetes mellitus. Other associated autoimmune diseases include pernicious anemia, Addison disease, and alopecia areata. Patients should be made aware of signs and symptoms that suggest the onset of hypothyroidism, diabetes, or other autoimmune disease. If signs or symptoms occur, appropriate tests should be performed. 
Thyrotropin testing is the most cost-effective screening test for thyroid disease. Antinuclear antibody screening is also helpful. A CBC count with indices helps rule out anemia.
Clinicians should also consider investigating for serum antithyroglobulin and antithyroid peroxidase antibodies, particularly if thyroid involvement is suspected. Antithyroid peroxidase antibodies are regarded as a sensitive and specific marker of autoimmune thyroid antibodies. Screening for diabetes can be accomplished with fasting blood glucose or glycosylated hemoglobin testing.
Vitiligo is diagnosed by means of inspection with a Wood lamp.
Microscopic examination of involved skin shows a complete absence of melanocytes in association with a total loss of epidermal pigmentation. Superficial perivascular and perifollicular lymphocytic infiltrates may be observed at the margin of vitiliginous lesions, consistent with a cell-mediated process destroying melanocytes. Degenerative changes have been documented in keratinocytes and melanocytes in both the border lesions and adjacent skin. Other documented changes include increased numbers of Langerhans cells, epidermal vacuolization, and thickening of the basement membrane. Loss of pigment and melanocytes in the epidermis is highlighted by Fontana-Masson staining and immunohistochemistry testing. [3, 4]
What would you like to print?