Phototoxicity in erythropoietic protoporphyria is when skin becomes red, blistered and swollen after being exposed to light, due to a build up of protoporphyrins which occurs in people who have the condition called erythropoietic protoporphyria.

What is phototoxicity

Phototoxicity is when a chemical reacts with light and causing the skin to become irritated.

What is erythropoietic protoporphyria

In the condition of erythropoietic protoporphyria (EPP) there is an inherited change in a gene (FECH gene) that causes a particular chemical called protoporphyrins to build up in the red blood cells (erythrocytes). When these red blood cells travel close to the skin they become exposed to light. The excessive protoporphyrin within the red blood cells absorbs light and becomes unstable, which damages the skin causing pain, redness and swelling.

How to prevent phototoxicity in EPP

Prevention of phototoxicity in EPP is by avoiding sunlight by using sun protective clothes including long sleeve tops, long pants, hats and sunglasses.  Sunscreens containing physical reflecting ingredients can reduce the amount of light penetrating the skin.

Medication to increase the skin pigmentation (melanin) can increase the skin tolerance to light

Drugs used to treat Prevention of Phototoxicity in Erythropoietic Protoporphyria