Erythropoietic Protoporphyria (EPP)
EPP is a rare metabolic disorder that causes severe, or phototoxic, reactions to light and affects approximately 10,000 people globally.
Patients with EPP have a deficiency of ferrochelatase, an enzyme which is involved in the formation of haemoglobin. This deficiency causes a precursor chemical called protoporphyrin IX to accumulate in the body and skin. Protoporphyrin IX is highly reactive with sunlight, resulting in severe inflammation and pain after only a few minutes of sun exposure.
EPP symptoms can occur suddenly (acute), or delayed (subacute), and are most often expressed as intense burning, tingling and itching of sun-exposed skin, followed by redness and swelling. Long-term exposure to light can cause scarring.
Phototoxicity is unresponsive to traditional pain and burn management techniques and patients can be incapacitated for days before reactions subside. Most patients must withdraw from light exposure in order to manage their symptoms.
Children and adults living with EPP must avoid sunlight and even reflected light for life, often staying indoors or wearing protective clothing. Conventional sunscreens have little to no effect as they do not block the wavelengths of light which cause phototoxicity in EPP.
What is Erythropoietic Protoporphyria?
Learn more about EPP.