In addition to phototoxic reactions, erythropoietic protoporphyria (EPP) patients can experience a number of other complications related to their condition.
Liver complications in erythropoietic protoporphyria
Approximately 80% of protoporphyrin IX (PPIX) molecules are produced by bone marrow, with the remaining 20% produced in the liver and, to a very minor extent, in other cells. The liver also extracts PPIX from blood and excretes PPIX into the bile. An excess of PPIX accumulating in the liver can affect its function and, ultimately, lead to liver failure.
A small number of EPP patients will, at some stage, have mild liver abnormalities caused by PPIX accumulation. While the exact figure is not known, between 1-5% of EPP patients are at risk of severe liver disease and liver failure.
Patients with the X-linked dominant form of EPP seem to be at increased risk of developing liver damage.
Jaundice is usually the first sign of liver failure in EPP patients. This may be accompanied by pain in the abdominal region, fatigue, enlargement of the liver and haemolysis. The development of jaundice is extremely serious and often life-threatening without a liver transplant.
Between 4-20% of erythropoietic protoporphyria patients are reported to have gallstones, often early on in life. Gallstones result from the accumulation of PPIX in bile which subsequently crystallises.
Vitamin D deficiency and osteoporosis
Vitamin D is produced by the body following exposure of skin to sunlight, specifically ultraviolet B radiation. Due to conditioned sun avoidance behaviour, erythropoietic protoporphyria patients generally receive too little sun exposure to enable vitamin D production in this way. UK research published in 2008 showed that 63% of EPP patients had insufficient vitamin D levels (
Mild anaemia – usually microcytic – in erythropoietic protoporphyria has been described in 20-60% of patients, with a slightly higher rate in women compared to men. Although this type of anaemia is similar to that seen with iron deficiency, other evidence of iron deficiency, such as a very low serum ferritin level, needs to be present before iron supplements are prescribed, as iron supplements may cause a worsening of the photosensitivity in EPP. Patients with the X-linked dominant form of EPP however usually respond well to iron supplements.
Chronic skin changes
Chronic changes to sun exposed skin are common in erythropoietic protoporphyria patients. Most will develop thickened, waxy or pitted scarring across the knuckles and/or nose as well as an “orange peel” effect around the lips and mouth. Scarring of the skin is common to most patients.