Small white or pale spots on the arms and legs are often harmless, but there are several possible causes. One particularly common cause in adults—especially with increasing age—is idiopathic guttate hypomelanosis (IGH).
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DermNet®
Common possibilities
Idiopathic guttate hypomelanosis: Tiny, flat, smooth white spots, often about 2–5 mm, appearing on sun-exposed forearms and shins. They become increasingly common with age and are considered benign.
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DermNet®
Vitiligo: Areas where pigment-producing cells are lost, producing more distinctly white patches. These can enlarge or appear in other locations.
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DermNet®
Tinea (pityriasis) versicolor: A yeast-related skin condition that can cause lighter patches, sometimes with fine scaling. It is more common in warm, humid environments.
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American Academy of Dermatology
Post-inflammatory lightening: Skin can remain lighter after eczema, an injury, infection, or other inflammation.
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American Academy of Dermatology
If they’re the typical tiny white dots
If they’re small, flat, painless, non-itchy spots on your forearms or lower legs, particularly if you’ve had them gradually appear over the years, IGH is a reasonable possibility. It generally doesn’t require treatment, although sun protection can help prevent further contrast between the spots and surrounding skin.
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DermNet®
Don’t try to diagnose white spots solely from their appearance. Rapidly spreading patches, scaling, itching, inflammation, or significant changes in pigmentation are good reasons to have a dermatologist examine them.
If you describe their size, whether they’re completely white or just lighter than your skin, whether they’re smooth or scaly, and where exactly they appear, I can help narrow down the possibilities.
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