Q: Three years ago, I discovered a 1mm round white spot on my right arm. Now, similar small white spots have appeared on both arms. There is also a reddish patch over the first white spot. Do the white spots indicate death of the skin cells and is there any treatment or way to prevent this? Will my skin turn white if I am covered by more spots? I am in my early 50s.

A: From your description, the white spots are likely to represent a condition known as Idiopathic Guttate Hypomelanosis.

This is thought to be an age-related condition with long-term sun exposure also possibly a factor. The spots are usually discreet, 1-3mm in size and affect mainly sun-exposed areas such as the forearms and shins.

Prevention methods include ensuring one has adequate sun protection. There is no consistently effective treatment for this, though various forms of therapy, including tretinoin creams and liquid nitrogen (cryotherapy), have been used with varying results.

However, there is no danger of large areas of skin turning white and the spots do not predispose one to skin cancer.

I am unable to comment on the cause of the reddish patch over the white spot which you have described without a proper consultation. I would recommend that you see a dermatologist for a more thorough assessment of your condition.

Dr Chris Foo
Specialist in dermatology at Raffles Hospital

This article was first published in Mind Your Body, The Straits Times.