Several months ago, my son developed a small white patch on the skin of his arm. It appears to be getting larger. Is a white patch on skin anything to be concerned about?

Answers from Lawrence E. Gibson, M.D.

Generally, a white patch on skin isn't cause for concern. Skin discoloration can be triggered by a number of causes, including:

  • Eczema. Sometimes a small area of skin becomes irritated or develops mild eczema, which results in a patch of skin that's lighter in pigment than is the skin around it. This is particularly common in children who have allergies, asthma or eczema. Your son's doctor may recommend applying moisturizer to the affected skin and avoiding harsh or drying soaps.
  • Superficial yeast infection. Another possible cause of a white patch on skin is a superficial yeast infection (tinea versicolor), which may cause the skin to look either lighter or darker than normal. In this case, treatment may include antifungal creams or shampoos.
  • Other skin diseases, including psoriasis and vitiligo, also may cause a light or white patch or other discoloration on skin. Treatment focuses on controlling the length and severity of flare-ups.

Consult a dermatologist for an evaluation if the white patch on your son's arm continues to enlarge or if additional white patches appear in other places.

Jan. 17, 2014