Was bald until age of three? No hair at all?

It wasn't like thin i was completely bald. Then I saw pic from age 4 where my hair was thick, poofy and curly. When I was born I had a full head of hair too be from like age 1-3 I was bald. Parents have always hinted it was medical but what could make a 1-3 year old bald? I know kemo does but I don't think they do that on babies nor have my patents ever told me I had cancer. P.s. I am 13 now and I do have something else unexplained. Under my nose is this spot that has no pigment in it so it's ghost white. Idk if that has anything to do with anything