White spots on skin usually come from one of a handful of common conditions, most of them harmless. The cause depends on the size, texture, and location of the spots, along with your age and how much sun exposure your skin has had over the years. Here’s how to tell what you’re likely dealing with and what, if anything, to do about it.
Fungal Overgrowth: Tinea Versicolor
The most common reason for scattered white (or tan, or pinkish) spots on the chest, back, and shoulders is a fungal condition called tinea versicolor. A yeast that normally lives on healthy skin overgrows and disrupts pigment production in small patches. The spots tend to be flat, slightly scaly, and more noticeable after sun exposure because the affected skin doesn’t tan like the surrounding areas.
Hot, humid weather, oily skin, and hormonal changes all increase the risk. Tinea versicolor is not contagious and isn’t caused by poor hygiene. It’s essentially your own skin yeast getting out of balance.
Over-the-counter antifungal treatments work well. Ketoconazole shampoo, applied to the affected skin for five minutes before rinsing, used once daily for five days, is a standard approach. Selenium sulfide shampoo works similarly. The fungus clears relatively quickly, but the color difference can take weeks or months to even out because your skin needs time to repigment those patches. Recurrence is common in warm climates, and some people use antifungal washes periodically to prevent flare-ups.
Sun Damage Over Time
Small, round white spots on the forearms and shins, each about 2 to 5 millimeters across, are a hallmark of a condition called idiopathic guttate hypomelanosis. These appear when pigment-producing cells in the skin slow down or stop working in tiny, scattered areas. The exact mechanism isn’t fully understood, but the contributing factors are well established: cumulative sun exposure, aging, genetics, and even minor repeated skin trauma like regular use of body scrubs.
The number of spots increases with age, and they’re far more common in people over 40 with lighter skin, though they occur across all skin tones. The spots are flat, smooth, and completely painless. They don’t spread to other people and they don’t indicate skin cancer or any systemic disease. There’s no reliable way to restore pigment to these spots. Sun protection can slow the development of new ones.
Vitiligo: When the Immune System Is Involved
Vitiligo produces white patches that are typically larger, more defined, and symmetrical compared to the spots caused by sun damage or fungal infections. The patches form because the immune system destroys melanocytes, the cells responsible for producing skin pigment. This is the most common form, called non-segmental vitiligo. A less common type, segmental vitiligo, results from chemicals released by nerve endings that are toxic to pigment cells, and it usually affects just one side of the body.
Globally, about 0.36% of the population has been diagnosed with vitiligo, roughly 28.5 million people. Prevalence is highest in Central Europe and South Asia. It can start at any age, though it often appears before 30. The patches can remain stable for years or gradually expand.
Treatment has improved significantly. The first FDA-approved topical treatment for vitiligo, a cream called Opzelura, works by blocking specific immune signals that drive the destruction of pigment cells. It’s approved for use on up to 10% of the body’s skin surface (your hand with fingers spread represents about 1%, so roughly ten “hands” worth of area). Phototherapy, which uses controlled UV light to stimulate pigment cells, remains another effective option. Many people with vitiligo see meaningful repigmentation with consistent treatment, though results vary.
Dry, Scaly Patches in Children
If your child has lighter patches of skin that look slightly dry or flaky, particularly on the face, arms, or upper body, this is most likely pityriasis alba. It’s one of the most common skin conditions in children and is closely related to eczema and atopic dermatitis. The patches aren’t truly white but rather lighter than the surrounding skin, and they’re more visible in children with darker complexions or after a tan.
Pityriasis alba isn’t caused by a fungus or an immune problem. It’s a mild inflammatory process that temporarily reduces pigment in affected areas. The patches may feel slightly rough or scaly. Daily moisturizing with a thick cream or petroleum jelly is the standard approach, and the condition resolves on its own over months to years. No treatment speeds up repigmentation, but keeping the skin well hydrated reduces the visible contrast and any itchiness.
Milia: Raised White Bumps, Not Flat Spots
If your white spots are small, raised bumps rather than flat patches, you may be looking at milia. These are tiny cysts that form when dead skin cells get trapped beneath the surface instead of shedding normally. New skin grows over the trapped cells, which harden into firm, white-to-yellow bumps, typically 1 to 2 millimeters across. They’re most common around the eyes, cheeks, and nose.
Milia aren’t acne and won’t respond to acne treatments. They’re painless, don’t become inflamed, and often resolve on their own. In newborns, milia are present at birth and disappear within a few weeks. In adults, they can persist longer. Resist the urge to squeeze them. A dermatologist can extract them easily with a small needle if they bother you cosmetically.
How to Tell the Difference
- Flat, slightly scaly, on the trunk: likely tinea versicolor, especially if the spots shift between lighter and darker shades seasonally.
- Tiny, smooth, round dots on forearms or shins: likely sun-related spots (idiopathic guttate hypomelanosis), especially if you’re over 40.
- Larger, well-defined, symmetrical patches: consider vitiligo, particularly if the patches have been slowly growing or appearing in new areas.
- Dry, faintly lighter patches on a child’s face: most likely pityriasis alba.
- Small, firm, raised bumps: milia, not a pigment issue at all.
The texture and location of white spots tell you more than the color alone. Scaly spots suggest fungal involvement or pityriasis alba. Completely smooth, well-bordered patches point toward vitiligo. Tiny uniform dots clustered on sun-exposed limbs suggest cumulative UV damage. If spots are changing rapidly, spreading to new areas, or accompanied by other symptoms like itching or hair loss, a dermatologist can confirm the diagnosis with a visual exam and, in some cases, a UV light called a Wood’s lamp that makes different conditions glow distinct colors.