[Erkhel]

I'm looking for help on behalf of my friend. She's a woman in her late 20s, who since the age of 15 has been getting headaches whenever she exposes the top of her head to sunlight. In the summer it takes only 30 seconds' exposure to give her a headache that lasts all day.

Sunglasses don't help, and heat alone (e.g. saunas) is no problem. Could this suggest there's a problem with UV exposure to her scalp? She's never dehydrated.

She's seeing a neurologist next month; it'd be a good idea to bring as much info, experience, and anecdotes as possible.