Summary about Disease
Erythropoietic Protoporphyria (EPP) is a rare inherited metabolic disorder characterized by extreme sensitivity to sunlight. It results from a deficiency in the enzyme ferrochelatase, which is necessary for the production of heme (a component of hemoglobin). This deficiency leads to the accumulation of protoporphyrin in red blood cells, plasma, and the skin. This excess protoporphyrin reacts with sunlight, causing painful skin reactions.
Symptoms
Burning, itching, and redness of the skin after even brief sun exposure.
Swelling of the hands and face.
Thickening and scarring of the skin over time (particularly on the hands and face).
Gallstones (due to increased protoporphyrin excretion).
Liver disease (in a small percentage of individuals).
Pain can be intense and disproportionate to the visible skin changes.
Causes
EPP is caused by a genetic mutation in the FECH gene, which provides instructions for making the ferrochelatase enzyme. It's typically inherited in an autosomal recessive pattern, meaning that an individual must inherit two copies of the mutated gene (one from each parent) to develop the condition. In some cases, a specific *ALAS2* gene mutation can cause X-linked dominant EPP.
Medicine Used
Afamelanotide (Scenesse): A synthetic melanocortin receptor agonist that stimulates melanin production, offering some protection against sunlight.
Beta-carotene: An antioxidant that can help reduce light sensitivity (though its effectiveness varies).
Ursodeoxycholic acid (UDCA): May be used to help prevent or treat gallstones and certain liver complications.
Cholestyramine: Used to bind protoporphyrin in the gut and reduce its enterohepatic circulation.
Liver Transplantation: In severe cases of liver failure.
Hematopoietic stem cell transplantation (HSCT): In rare cases.
Is Communicable
No, EPP is not communicable. It is a genetic disorder, not an infectious disease.
Precautions
Strict avoidance of sunlight (including indirect sunlight and light through windows).
Wearing protective clothing (long sleeves, hats, gloves).
Using high SPF, broad-spectrum sunscreen (although its effectiveness is limited).
Tinting windows in homes and cars.
Avoiding prolonged exposure to artificial light sources (some may trigger reactions).
Monitoring liver function regularly.
Iron supplementation, if iron deficient.
How long does an outbreak last?
The duration of an EPP "outbreak" (i.e., a skin reaction) varies depending on the intensity and duration of sun exposure. Reactions can last from several hours to several days. The pain can persist even after the visible skin changes have subsided.
How is it diagnosed?
Clinical evaluation: Based on symptoms and medical history.
Blood tests: To measure protoporphyrin levels in red blood cells and plasma.
Genetic testing: To identify mutations in the FECH or *ALAS2* gene.
Urine and Stool porphyrin analysis: To differentiate from other porphyrias
Liver function tests: To assess for liver involvement.
Timeline of Symptoms
Childhood: Symptoms usually begin in early childhood (often before age 5).
Immediate: Burning pain starts within minutes of sun exposure.
Hours: Redness and swelling develop.
Days: Symptoms gradually subside, but pain can linger.
Years/Decades: Chronic sun exposure leads to thickening and scarring of the skin, particularly on the hands and face. Gallstones and liver problems can develop over time.
Important Considerations
EPP significantly impacts quality of life due to chronic pain and limitations on outdoor activities.
Early diagnosis and strict sun avoidance are crucial to prevent long-term complications.
Genetic counseling is recommended for families with EPP.
Liver disease is a serious potential complication that requires ongoing monitoring.
Patients with EPP should inform healthcare providers about their condition before any medical procedures or treatments, as some medications and light sources may trigger reactions.