A friend is extremely sensitive to direct sunlight.  After a few
minutes exposure (anywhere), it becomes visibly bumpy and irritated.
If she allows exposure to last a long time, she starts to feel quite
sick.  I've seen the effects myself, and it's pretty upsetting.
Sunscreens have little effect, but clothing reduces exposure.
Antihistamines help the allergic reactions somewhat.

She's under 30, black, no history of skin trouble, no special
sensitivity to the sun.  The problems started in the last two years.

She's tried several dermatologists without success.  Someone sold her
on macrobiotics, so she tried that too.  It didn't help the skin
problem at all.  

Has anyone on the net any experience with this problem??  It's
effectively moved her life indoors.  Or, can someone recommend
fruitful searches in the literature?

t