Summary about Disease
Erythropoietic protoporphyria (EPP) is a rare, inherited metabolic disorder primarily affecting the skin. It's caused by a deficiency in the enzyme ferrochelatase, which leads to a buildup of protoporphyrin (a type of porphyrin) in red blood cells, plasma, and eventually the skin. This excess protoporphyrin makes the skin extremely sensitive to sunlight and certain types of artificial light. Liver disease can occur in some individuals.
Symptoms
The main symptom is painful, non-blistering skin reactions after even brief exposure to sunlight or some artificial lights (like halogen). Symptoms usually begin in childhood. Other symptoms can include:
Burning, itching, redness, and swelling of the skin
Pain that can be severe
Thickening and scarring of the skin over time (especially on the hands and face)
Gallstones (due to excess protoporphyrin in the bile)
Liver problems (in a minority of patients)
Causes
EPP is caused by mutations in the FECH gene, which provides instructions for making the ferrochelatase enzyme. This enzyme is responsible for inserting iron into protoporphyrin to form heme, a component of hemoglobin (the oxygen-carrying protein in red blood cells). A defective *FECH* gene reduces the amount of functional ferrochelatase, leading to the accumulation of protoporphyrin. It is typically inherited in an autosomal recessive pattern, meaning that an individual must inherit two mutated copies of the gene (one from each parent) to develop the condition. However, a more complex inheritance pattern is also seen.
Medicine Used
Afamelanotide (Scenesse): A synthetic melanocortin receptor agonist that stimulates melanin production, providing some protection from sunlight. This is the primary treatment option.
Beta-carotene: An antioxidant that can help to reduce the photosensitivity of the skin.
Ursodeoxycholic acid (UDCA): Used to treat or prevent gallstones and manage liver complications.
Cholestyramine: Binds to protoporphyrin in the intestine, helping to eliminate it from the body and reduce the risk of liver damage.
Blood transfusions: May be used in severe cases to reduce the amount of protoporphyrin in the blood.
Is Communicable
No, EPP is not communicable. It is a genetic disorder and cannot be spread from person to person.
Precautions
Strict sun avoidance: This is the most important precaution. Wear protective clothing (long sleeves, hats, gloves), use broad-spectrum sunscreen with a high SPF (although it might not be fully effective), and avoid being outdoors during peak sunlight hours.
Window tinting: Tint windows in cars and homes to block UV light.
Specific Light Bulbs: Use incandescent light bulbs that emit less UV light or install special filters on fluorescent or halogen lights.
Monitor liver function: Regular blood tests to check liver function are crucial.
Avoid known triggers: Some medications or substances might worsen symptoms. Discuss these with your doctor.
Avoid alcohol: Alcohol can increase the risk of liver damage.
How long does an outbreak last?
The duration of an EPP reaction varies depending on the intensity of sun exposure and individual sensitivity. Reactions can last from several hours to several days. The pain may subside in a few hours, but redness, swelling, and itching can persist for days.
How is it diagnosed?
Clinical evaluation: Based on the symptoms and medical history.
Blood tests: To measure the levels of porphyrins (specifically protoporphyrin) in red blood cells and plasma.
Urine and stool tests: To measure porphyrin levels.
Genetic testing: To identify mutations in the FECH gene.
Skin biopsy: Rarely, a skin biopsy may be performed to examine the tissue under a microscope.
Timeline of Symptoms
Infancy/Early Childhood: Symptoms typically appear in early childhood, often with the first significant sun exposure.
Childhood/Adolescence: Photosensitivity and associated pain continue. Repeated exposure can lead to skin thickening and scarring over time.
Adulthood: Symptoms persist, but some individuals may experience a slight lessening of photosensitivity with age. Liver complications may develop in adulthood.
Important Considerations
Psychological impact: EPP can significantly impact quality of life due to the limitations imposed by photosensitivity. Psychological support may be beneficial.
Vitamin D deficiency: Due to sun avoidance, individuals with EPP are at increased risk of vitamin D deficiency and may require supplementation.
Liver disease: While not all individuals with EPP develop liver disease, regular monitoring is essential. If liver disease occurs, it can be serious and may require specialized treatment.
Medication Interactions: Discuss all medications and supplements with your doctor, as some can worsen EPP symptoms or affect liver function.
Emergency Situations: Patients should carry identification indicating they have EPP and the need for avoiding sunlight.