Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
Call emergency services for a seizure lasting several minutes, sudden severe weakness, loss of consciousness, choking with inability to breathe, or another immediately life-threatening symptom.
These are emergency signs regardless of whether someone has XP.
Arrange a prompt medical or dermatology assessment for a new or changing mole, a lump, a scaly patch that persists, or a sore that does not heal.
Bleeding, crusting, rapid growth, changing colour, or an irregular border also need timely review.
These signs do not always mean cancer, but they should not wait until the next distant routine appointment.
Report increasing eye redness, discomfort, light sensitivity, eyelid changes, or a gradual change in vision promptly to an eye specialist.
Seek urgent same-day care for severe eye pain, a sudden loss or major change in vision, or a chemical or UV injury to the eyes.
Routine appointments are appropriate for planned skin and eye checks, hearing monitoring, vitamin D review, equipment questions, and gradual changes in mobility or learning.
Every sign above is quoted from the sofidex article on Xeroderma pigmentosum. If you are not sure, err upward — it is always reasonable to be checked.