Untannable spot, used to be a mole

Just curious as to what this could be. I used to have a small birthmark on my right arm and my sister had the same thing. Hers is still there, but mine disappeared about 4 years ago into a white, tanless spot. The hairs that grow from it are also colorless leading my untrained mind to believe there's no melanin in the area.  The spot still burns, and is a very good indicator of whether or not I stayed out in the sun too long because it's the first spot to get pink/red

All I can think is that maybe it's a scar from my birthmark.

[Bhupinder Kaur, MD]

Hello,
If such changes have appeared in place of a mole, then you should get it evaluated and also get vitiligo ruled out. As a thumb rule, if you notice changes in the mole's/mark’s color, height, size or shape, you should have a dermatologist evaluate it. You also should have it checked if it bleeds, oozes, itches, appear scaly, or become tender or painful.

It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your doctor. I sincerely hope that helps. Take care and please do keep me posted on how you are doing.