4th July 2023

Investigations

Photosensitivity is usually a clinical diagnosis, but investigations can be done to try and identify the underlying cause. This includes blood tests (full blood count, renal profile, liver function tests, iron studies, autoimmune screen and porphyrias) and stool and urine samples. Autoimmune screens are to look for connective tissue conditions and stool/urine samples are used to check for porphyrins if suspecting porphyria. Rarely, contact photosensitivity tests can be carried out where a photosensitising patch is applied to the skin and checked 2 days after the light is shone to the area.