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.

Tests and diagnosis

Medical history and exam
If your doctor suspects you have vitiligo, he or she will ask about your medical history and examine you. Important factors in your medical history include:

• A family history of vitiligo or an autoimmune disease
• A personal history of sun sensitivity or other skin conditions
• A rash, sunburn or other skin trauma within two to three months of the start of pigment loss
• A history of melanoma or multiple, atypical moles
• Premature graying of the hair (before age 35)
• Stress or physical illness

• Your doctor will also examine you to rule out other medical problems or skin conditions, such as dermatitis or psoriasis. He or she may use a device called a Woods lamp, which shines ultraviolet (UV) light onto the skin, to determine whether you have vitiligo.

Skin biopsy and blood draw
In addition to gathering your personal and family medical history and examining your skin, your doctor may also:

• Take a small sample (biopsy) of your affected skin
• Draw blood to check your blood cell count, thyroid function and to look for the presence of anti-nuclear antibodies (a type of autoantibody) that would indicate an autoimmune diseas

• Additionally, your doctor may recommend that you see an eye specialist (ophthalmologist) for an eye examination to check for inflammation in your eye (uveitis).