Correct Answer:  5. Hepatitis C antibody

Explanation: Porphyria cutanea tarda presents with vesicles and erosions with milia and scarring on sun-exposed skin, classically the dorsal hands. There is a deficiency in uroporphyrinogen decarboxylase (UD) and urine uroporphyrinogen is elevated. The most common associated conditions are Hepatitis C, HIV, iron overload states (hemochromatosis) and environmental triggers (alcohol, estrogens, polyhalogenated hydrocarbons). Treatment includes phlebotomy and low dose oral antimalarials.