These spots are usually:
- Small and round or oval
- White or noticeably lighter than the surrounding skin
- Flat rather than raised
- More common on the forearms and lower legs
- Usually painless and not itchy
They can become more noticeable over time, particularly in people with significant lifetime sun exposure.
The word “idiopathic” means that the exact cause isn’t fully understood. However, age and cumulative ultraviolet exposure are thought to play important roles.
IGH is not contagious, and the spots themselves are generally harmless.
If you have many tiny, sharply defined white spots that have gradually appeared on sun-exposed areas, IGH may be one possibility.
2. Sun Exposure Can Make White Spots More Noticeable
The contrast between lighter spots and surrounding skin can become more obvious after tanning.
Imagine that the normal skin becomes darker from sun exposure while an area with reduced pigment remains lighter. The spots may suddenly appear much more prominent, even though the underlying condition has not dramatically changed.
