You're going about your day, maybe getting dressed or glancing at your arms in the sunlight, and you notice them: small, white spots scattered across your skin. They're not raised. They don't itch. They're just... there. Pale little patches that stand out against your normal skin tone.

If you've noticed these spots, you're not alone. They're surprisingly common, especially as we age. But what are they? Are they harmless? And is there anything you can do about them?

Let's explore the most likely causes—and when you might want to mention them to a doctor.

The Most Common Cause: Idiopathic Guttate Hypomelanosis

The medical name is a mouthful, but the condition itself is simple: idiopathic guttate hypomelanosis (often called IGH).

Let's break it down:

Idiopathic – The cause isn't fully understood
Guttate – Latin for "teardrop-shaped"
Hypomelanosis – Loss of skin pigment

What it looks like:

Small, flat white spots, usually 1-5mm in size
Most commonly on sun-exposed areas: shins, forearms, shoulders
Smooth texture (not scaly or raised)
More common as we age (often starting after 40)

What causes it?
While the exact cause isn't known, IGH is strongly associated with:

Sun exposure over many years (it's most common on sun-exposed skin)
Natural aging – the spots become more common as we get older
Genetics – some people are simply more prone to them

Is it harmful?
No. IGH is completely harmless. It doesn't turn into skin cancer, doesn't spread to other people, and doesn't affect your overall health. It's purely a cosmetic concern.