Well, time to become a detective...

Look at all the things you share... bug bites (mosquito and tick),
vaccines (did you all get flu shots?), water (have it tested,for heavy metals), airborne (formaldehyde outgassing in the house, mold spores, industrial fumes, second hand smoke), foods (arsenic in rice, too much green stuff (see the recent post here on oxalate excess), that awful Himalyan salt,
the stuff you wash your clothes in (get sensitive soaps).

One thing that is a big cause of photosensitive dermatitis is the blue green algae in water. Right now Northern Ohio is having another microcystin attack from Lake Erie in their municipal water supply. This invisible to the naked eye, organism sits on skin that was exposed to the water, and reacts with UV to form dermatitis. Many people where we live in summers, have had this reaction including me. Many are fishermen who get this on their hands and arms.

http://www.tpchd.org/environment/sur...cyanobacteria/

Search the internet for an environmental doctor...they have a website, that might be helpful. Or call your local hospital to see if they know of a doctor who specializes in toxins.
http://www.aaemonline.org/referral.php