White spots on skin are areas where pigment has been lost or reduced, and they have several possible causes ranging from harmless fungal infections to autoimmune conditions like vitiligo. The most common culprits are tinea versicolor (a superficial yeast infection), pityriasis alba (linked to eczema), sun damage over time, and vitiligo. What’s causing yours depends on the size, location, texture, and whether the spots are spreading.
Tinea Versicolor: A Common Fungal Cause
Tinea versicolor is one of the most frequent reasons people notice white spots, especially on the trunk, neck, and abdomen. It’s caused by a yeast called Malassezia furfur that naturally lives on everyone’s skin but occasionally overgrows. When it does, it interferes with normal pigment production and leaves behind scaly patches that can range from white to tan, pink, or brown. The patches tend to become more noticeable after sun exposure because the affected skin doesn’t tan like the surrounding areas.
The telltale sign of tinea versicolor is fine scaling on the surface of the spots. If you lightly scratch a patch and see a thin flake of skin lift off, that’s a strong clue. The spots are usually not itchy or painful, though some people notice mild itching in hot weather. This condition is especially common in warm, humid climates and in teenagers and young adults whose skin produces more oil.
Treatment is straightforward. Over-the-counter antifungal shampoos containing selenium sulfide or pyrithione zinc can be applied directly to the skin for one to two weeks. Prescription antifungal creams are another option, typically used daily for about two weeks. One thing that surprises people: even after the yeast is gone, the white spots can linger for weeks or months until your skin gradually repigments. That delay doesn’t mean the treatment failed.
Vitiligo: When the Immune System Targets Pigment Cells
Vitiligo causes smooth, completely white patches where the skin has lost all pigment. Unlike tinea versicolor, vitiligo patches have no scaling or texture change. The condition is autoimmune, meaning the body’s immune system mistakenly attacks and destroys melanocytes, the cells responsible for producing skin color. Research suggests that melanocytes in people with vitiligo may be more vulnerable to environmental stress from things like chemicals or ultraviolet radiation, making them more likely targets for immune attack.
There are two main forms. Non-segmental vitiligo is the most common and causes patches on both sides of the body, often symmetrically, on areas like the hands, face, elbows, and knees. Segmental vitiligo is less common and appears on just one side of the body in a limited area. Both forms can start at any age, though many people first notice patches in their twenties or thirties.
Vitiligo patches tend to spread over time, though the speed varies enormously. Some people have a few small spots that stay stable for years. Others experience rapid expansion. Treatment focuses on restoring pigment or slowing the spread. Prescription corticosteroid creams can be effective for both children and adults when used for limited periods as directed by a dermatologist. For sensitive areas like the face, calcineurin inhibitor creams offer an alternative that can be used for longer stretches without the skin-thinning side effects of steroids.
Pityriasis Alba: White Patches in Children
If your child has pale, slightly rough patches on the cheeks, arms, or trunk, pityriasis alba is the likely explanation. This condition is closely linked to eczema and is extremely common in school-age children. The patches start as mildly pink or red areas that fade into lighter spots as the inflammation resolves. They’re more visible on darker skin tones and tend to stand out after sun exposure.
Pityriasis alba resolves on its own, though it can take many months for the patches to return to normal pigment. Keeping the skin moisturized helps with any dryness or mild flaking. No specific treatment is usually needed.
Sun Damage Spots That Appear With Age
Small, flat white spots on the forearms, shins, and other sun-exposed areas are often a condition called idiopathic guttate hypomelanosis. These spots are usually smaller than a pea, though some can grow as large as a quarter. They become more numerous with age and are thought to result from cumulative UV exposure gradually damaging the pigment-producing cells in those areas.
These spots are harmless and permanent. They don’t spread to unexposed areas or indicate any underlying disease. Because the melanocytes in those tiny patches have been permanently damaged, the spots don’t respond well to treatment, though some people pursue cosmetic procedures if the appearance bothers them.
Post-Inflammatory Hypopigmentation
Any skin injury or inflammation can temporarily disrupt pigment production in the affected area. Burns, cuts, acne, psoriasis flares, eczema patches, and even cosmetic procedures like laser treatments or chemical peels can leave behind lighter spots as the skin heals. This is especially noticeable on brown and black skin, where psoriasis in particular often leaves discolored patches after it resolves.
The good news is that post-inflammatory hypopigmentation typically resolves on its own within a few weeks to months as your skin cells resume normal melanin production. No treatment is usually necessary beyond letting the area heal.
Milia: Raised White Bumps, Not Flat Spots
If your white spots are actually small, raised bumps rather than flat patches, you may be looking at milia. These are tiny cysts formed when dead skin cells become trapped beneath the surface instead of shedding normally. New skin grows over them, and the trapped cells harden into firm, white-to-yellow bumps. They’re commonly found on the face, particularly around the eyes and cheeks.
Milia are often confused with whiteheads, but they aren’t a form of acne. They don’t respond to acne treatments. In newborns, milia are extremely common and resolve without intervention. In adults, they can be removed by a dermatologist with a small needle or blade if they’re cosmetically bothersome, but they pose no health risk.
How Dermatologists Tell These Apart
A dermatologist can often diagnose the cause of white spots by appearance alone, but when the cause isn’t obvious, a Wood’s lamp examination is a common next step. This handheld UV light causes different skin conditions to fluoresce in distinct colors. Depigmented skin from vitiligo glows bright blue-white, fungal infections like tinea versicolor appear blue-green, and certain yeast infections show up as yellow or orange. This quick, painless test can distinguish between a fungal infection and an autoimmune condition in seconds.
In some cases, a skin biopsy is necessary. This is particularly important when white patches don’t behave like any of the common causes. A rare condition called hypopigmented mycosis fungoides, a type of skin lymphoma, can mimic vitiligo closely enough that it’s one of the most common misdiagnoses. It tends to cause patches that are slightly different in texture or distribution than typical vitiligo. While rare, it requires proper evaluation because it needs a different treatment approach entirely. Patches that are persistent, slowly growing, and don’t respond to standard treatments warrant a dermatology visit for closer evaluation.
Matching Your Spots to the Most Likely Cause
- Scaly patches on the trunk or neck: Most likely tinea versicolor, especially in warm weather.
- Smooth, milk-white patches with sharp borders: Characteristic of vitiligo, particularly if symmetric on both sides of the body.
- Pale, slightly rough patches on a child’s face: Pityriasis alba, especially if the child has a history of eczema.
- Tiny flat spots on forearms or shins in someone over 40: Likely idiopathic guttate hypomelanosis from cumulative sun exposure.
- Light patches where you previously had a rash, burn, or injury: Post-inflammatory hypopigmentation, which typically fades on its own.
- Small, firm, raised white bumps on the face: Milia, which are keratin-filled cysts rather than a pigment issue.