Vitiligo shows up as milky-white patches where your skin has completely lost its pigment. It affects roughly 0.3 to 0.5 percent of people worldwide, can appear at any age, and occurs equally in men and women. If you’ve noticed white or lighter spots on your skin, here’s how to tell whether vitiligo is the likely cause or something else entirely.
What Vitiligo Patches Look Like
The hallmark of vitiligo is smooth, flat patches of skin that have turned completely white, not just lighter than your surrounding skin tone. The color is often described as milky-white, and the patches feel normal to the touch. They don’t itch, flake, or feel rough. If a spot is scaly, raised, or uncomfortable, that points toward a different condition.
In the most common form (non-segmental vitiligo), patches appear symmetrically on both sides of your body. If you notice a white spot on one hand, check the other. Matching patches on both knees, both wrists, or both sides of your face are a strong visual clue. The patches tend to have relatively distinct borders where normal skin meets depigmented skin, though very early patches may start as lighter areas that gradually lose more color over time.
Where Patches Typically Appear First
Vitiligo has preferred locations. It commonly starts on the face, neck, scalp, and around body openings like the mouth, nostrils, eyes, and genitals. The hands, arms, and areas where bones sit close to the surface (knuckles, elbows, knees, ankles) are also frequent early sites. Spots also tend to develop in areas that experience repeated friction or pressure, like waistbands, bra straps, or watch bands.
This pattern happens because of something called the Koebner phenomenon: skin trauma, even minor rubbing or scratching, can trigger new patches of pigment loss at the injury site. New spots from this process typically appear within 10 to 20 days of the skin being irritated and often run in a straight line following the path of the scratch or friction.
Signs the Condition Is Spreading
Not all vitiligo behaves the same way. Non-segmental vitiligo, the more common type, tends to spread slowly over time. New patches develop on and off, sometimes over years or even decades. You might go months without any change, then notice a new spot appearing.
Segmental vitiligo behaves differently. It affects only one side or one section of the body, like one arm, one leg, or one half of the face. It spreads rapidly for about 6 to 12 months, then typically stabilizes and stops. Most people with this form don’t develop new patches after that initial burst.
An active, progressing patch often has blurry or irregular borders and may show a “trichrome” pattern, where you can see three distinct shades blending together: white in the center, a lighter tan zone, and your normal skin color at the edges. Once vitiligo stabilizes in an area, the borders become sharp and well-defined. If you’re seeing small dark dots returning inside a white patch, especially around hair follicles, that’s actually a sign of repigmentation, meaning some color is coming back.
Hair and Mucous Membrane Changes
Vitiligo doesn’t just affect skin. The same pigment-producing cells exist in hair follicles and mucous membranes, so you may notice white hairs growing within a patch of vitiligo, or even a patch of white hair on your scalp, eyebrows, or eyelashes before the surrounding skin loses color. Pigment loss can also occur on the lips or inside the mouth. White hair within a depigmented patch is actually a meaningful clinical sign, as it suggests the pigment cells in that area have been more thoroughly lost.
Conditions That Look Similar
Several other skin conditions cause lighter spots, and telling them apart is one of the most important steps in figuring out whether you have vitiligo.
- Tinea versicolor: A common fungal infection that causes lighter patches on the chest and back. The key difference is that these spots become scaly if you scratch them with a fingernail. Vitiligo patches stay smooth.
- Pityriasis alba: Pale, slightly rough patches that commonly appear on children’s cheeks, the fronts of elbows, or backs of knees. These are linked to eczema and are lighter than surrounding skin but not completely white.
- Idiopathic guttate hypomelanosis: Tiny white dots, usually 1 to 2 millimeters across and almost always under 5 millimeters, that appear on sun-exposed areas like the shins and forearms. They stay small and don’t spread the way vitiligo does.
- Nevus depigmentosus: A birthmark that appears in the first few months of life. It has jagged edges, doesn’t turn hair white, and doesn’t grow rapidly. It may stretch as a child grows but won’t expand quickly the way vitiligo can.
- Lichen sclerosus: White patches typically on the genitals that come with itching, pain, or cracking. Vitiligo in the same area causes color loss but no discomfort.
If lighter spots are limited to sun-protected areas like the trunk and groin (a “bathing suit” distribution), that can sometimes indicate a rare form of skin lymphoma rather than vitiligo, which is another reason unusual patterns deserve a professional evaluation.
How a Dermatologist Confirms It
Vitiligo is usually diagnosed through a visual examination alone. A dermatologist will look at the distribution, symmetry, and characteristics of your patches. The most helpful diagnostic tool is a Wood’s lamp, a handheld ultraviolet light used in a darkened room. Under this light, vitiligo patches glow a bright blue-white, making them easier to see and distinguish from other conditions, especially on lighter skin where the patches might be subtle in normal lighting. The exam is painless and takes just a few minutes.
In uncertain cases, a small skin biopsy can confirm the absence of pigment-producing cells. A dermatologist may also scrape a patch to test for fungal infection if tinea versicolor is a possibility.
Blood Tests Your Doctor May Order
Vitiligo itself doesn’t require blood work to diagnose, but because it’s an autoimmune condition, it’s associated with other autoimmune diseases. Thyroid disease is the most common overlap. Current guidelines recommend screening thyroid function (TSH levels) and thyroid antibodies once vitiligo is confirmed. Your doctor may also check for other conditions like diabetes, anemia, or autoimmune hair loss if you have symptoms suggesting those. These tests aren’t done to diagnose vitiligo but to catch related conditions early.
What to Look for Before Your Appointment
Before seeing a dermatologist, it helps to document what you’re noticing. Take photos of each spot in good lighting and note when you first saw them. Track whether patches have grown or new ones have appeared, and how quickly. Pay attention to whether the spots are on both sides of your body or just one, whether the hair in those areas has turned white, and whether the patches itch or flake.
These details help a dermatologist distinguish vitiligo from lookalikes quickly. Completely white and smooth patches that are symmetrical, appear in typical vitiligo locations, and have been gradually spreading are a strong clinical picture. Patches that are only slightly lighter than your normal skin, that scale when scratched, or that appeared at birth point toward other diagnoses.