As a result of absorption of ultraviolet and visible light (peak sensitivity at 400 nm, with lesser peaks between 500-625 nm) by protoporphyrin in plasma and erythrocytes when blood circulates through the dermal vessels, free radicals are formed, erythrocytes become unstable and injury to the skin is induced.A significant increase in the hepatobiliary excretion of protoporphyrin can damage the liver through both cholestatic phenomena and oxidative stress - predisposing to hepatobiliary disease of varying degrees of severity

Diagnosis
EPP is generally suspected by the presence of acute photosensitivity of the skin and can be confirmed by detection of a plasmatic fluorescence peak at 634 nm. It is also useful to find increased levels of protoporphyrin in feces and the demonstration of an excess of free protoporphyrin in erythrocytes.Screening for FECH mutation on one allele or aminolevulinic acid synthase 2 gain-of-function mutation in selected family members may be useful, especially in genetic counseling. Liver biopsy confirms hepatic disease in EPP by the presence of protoporphyrin deposits in the hepatocytes that can be observed as a brown pigment within the biliary canaliculi and the portal macrophages. Macroscopically, the cirrhotic liver can have a black color due to protoporphyrin deposits. Using polarized light the characteristic Maltese cross shape of birefringent crystalline pigment deposits is found. The examination of liver tissue under a Wood’s lamp reveals a red fluorescence due to protoporphyrin. Liver biopsy is not helpful for estimation of prognosis of liver disease.
Endemic goiter is a type of goitre that is associated with dietary iodine deficiency. Cause
Some inland areas where soil and water lacks in iodine compounds and consumption of marine foods is low are known for higher incidence of goitre. In such areas goitre is said to be "endemic". Prevention
This type of goiter is easily preventable. In most developed countries regulations have been put into force by health policy institutions requiring salt, flour or water to be fortified with iodine. Treatment
Treatment of endemic goiter is medical with iodine and thyroxine preparations. Surgery is only necessary in cases where complicated by significant compression of nearby structures. References


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