patch of skin wont tan

[vbudd]

ok, so i've been seeing a dermatologist for about a year.  i have white colored skin patches on my left arm and shoulder and back around the shoulder.  They are very white looking whenever i work out and the normal skin gets red or i get in the sun and the normal skin gets red then too.  it is not raised, scaly, or anything like that, just white.  My dermatologist has treated it as tinea versicolor with first the cream then the pills which did nothing.  they nolonger think its tinea versicolor.  i dont either.  then she thought it might be dry skin and i've been moisturizing for about a month with no change.  she said the only other option was a biopsy bcus it may be sun damage which was what i thought it was initially.  help please?  its a superficial problem but it really bugs me,

[vbudd]

and i've only seen it for the past couple of years

[vbudd]

They do not move at all, and even in the winter when i get no sun they are whiter than my normal skin; and its only around the one shoulder.  

[Vanessa Lacuesta]

Hi,

Are there several similar patches of white skin in other parts of the body?

One differential to consider here also aside from a photosensitivity reaction is a vitiligo. Was this differential considered by your physician?

Vitiligo is a chronic condition and is due to true lack of melanocytes ( cells responsible for pigmentation)  in the area. The involved areas are stark white with  well defined borders delineating it from normally colored skin. Vitiligo may involve focal or small patches of skin. The cause has both autoimmune and genetic components. It is best to ask your physician about this.

Do the patches revert to normal skin after sun exposure?

Do they expand?