photosensitivity | Notion

Photosensitivity describes a group of skin disorders that result from exposure to normal levels of UV light exposure

Fitzpatrick skin types

Normal human skin is photosensitive in that it reddens/tans following following acute sunlight exposure, and thickens following chronic sunlight exposure
Photosensitivity is multi-factorial with it being influenced by the intensity of UV light, genetics, genetics, drugs and skin types

Type	Skin colour	Reaction to light
1	Very fair	Always burns, never tans
2	Fair	Usually burns, sometimes tans
3	Medium	Sometimes burns, usually tans
4	Olive	Rarely burns, always tans
5	Brown	Never burns, always tans
6	Black	Never burns, always tans

Xeroderma pigmentosum

Xeroderma pigmentosum refers to a group of autosomal recessive genetic disorders caused by a deficiency in the DNA repair mechanisms in the skin

Clinical features

Severe photosensitivity
Accelerated photo ageing
Ocular damage
Early formation of skin cancers

Management

Patients are required to undertake strict sun avoidance
Most will die in teenage or early adult years due to skin cancer