My aunt was recently told she has a sun allergy called PMLE, which is often a hereditary form of sun allergies. She has been taking beta carotene capsules to help her with this.
She does not know anyone in her family who has been diagnosed with this before. When she is outside in direct sunlight for more than a few minutes she gets a red, itchy rash on her body. She said she doesn't know if the beta carotene is really doing any good, but figures it can't really be hurting her.
She also avoids being outside for very long and usually wears long sleeves and makes sure most of her skin is not directly exposed to the sun.