EPP Kids' Program
Camp Discovery Summer Time Parents and Kids!
Disneyland and Disney World are responsive to people with sun sensitivity. They will provide a pass to enable you to enter attractions without waiting in line in the sun.
Go to "City Hall" and explain your problem of photosensitivity. You should bring a physician's letter with you as well as an APF brochure explaining the cutaneous disorder.
Proceed to the "Guest Relations" office at any of their parks (Magic Kingdom, EPCOT, etc.) and request the Special Assistance Pass.