Porphyria cutanea tarda is a physical exam finding sometimes associated with hereditary hemochromatosis. There is blistering, erosions and fragility of the skin in areas with direct exposure to sunlight. Hyperpigmentation or hypertrichosis can be seen as well.
In the case of iron excess (and sometimes with contributions from hepatitis C or alcohol abuse) there is increased demand for heme production and the enzymes required to make heme. This can deplete the enzyme uroporphyrinogen decarboxylase (UROD) from hepatocytes, disrupting heme production and allowing byproducts to accumulate in the body.