White spots on skin can have a number of causes. Here are a few of the more common:

Milia
Occurs on the face and is a build-up of dead skin cells that are not able to get out of the skin. Its not an infection. It has no bacteria or pus. The only way to remove Malia is to have them extracted from the skin. Exfoliation is the best prevention.

Pityriasis Alba
These are rounded white patches on the skin. It is characterised by a temporary loss of pigmentation. Its not contagious and usually occurs on the extremities, upper trunk and neck. This will often occur after sun exposure and could be a mild atopic or allergic dermatitis. The condition can last up to 3 years. Topical hydro-cortisone can be useful in providing cosmetic relief.
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