Tiny white spots on the arms or legs are often harmless, but their cause depends on their appearance, distribution, and whether they are changing.
One common cause is idiopathic guttate hypomelanosis (IGH)—small, flat, pale or white spots that commonly appear on sun-exposed arms and legs, particularly with increasing age. They aren’t contagious and generally don’t require treatment.
Other possibilities include:
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Tinea versicolor — a superficial fungal infection that can produce lighter patches, sometimes with fine scaling.
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Vitiligo — areas where pigment is lost, often becoming more distinctly white and sometimes gradually expanding.
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Post-inflammatory hypopigmentation — lighter areas left behind after irritation, injury, eczema, or another rash.
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Sun-related changes — repeated sun exposure can contribute to uneven pigmentation.
When to have them checked
See a dermatologist or clinician if the spots are new and rapidly spreading, completely depigmented, itchy/scaly, painful, bleeding, or associated with other symptoms.
A photo or physical examination is usually more useful than trying to diagnose white spots from their appearance alone.
