Ultraviolet exposure to the face in patients with xeroderma pigmentosum and healthy controls: applying a novel methodology to define photoprotection behaviour.

Photoprotection behaviour varies widely within the XP group indicating that non-adherence to photoprotection advice is a significant issue. Timing and duration of going outside are as important as photoprotective measures taken when outside, to determine the UVR exposure to the face. This new methodology will be of value in identifying the sources of UVR exposure in other conditions where facial UV exposure is a key outcome, particularly in patients with multiple non-melanoma skin cancers.