Childhood

Charlie Brown is dying of cancer

Oof. This one hurts. According to at least one theorist, "My personal explanation for why Charlie Brown in Peanuts is bald is he's dying of cancer and dreaming up everything. In the strip nothing ever works out for him and his life is a disaster, but he's simply channeling his sadness into his dreams."

Source - Flavorwire.com
My opinion - wow! This reminds me of another cartoon theory! I have to give this theory a 3/10 for the lack of evidence