Hair loss

My daughter will be 5 months on august 2nd. She was born with a full head of hair and is now going bald in a few spots. It’s a bit concerning to me as this didn’t happen to my son (he was born with a bit less hair then her) her pediatrician doesn’t seemed concerned but I’m just hoping it gets better and her hair grows back. She also had very bad cradle cap that has gotten better since I drench it in baby oil. Not sure if that has anything to do with it. Looking to see if anyone else had a similar situation 🙂 first pic is her hair when she was born, other pics are now