Porphyria cutanea tarda (PCT) is a metabolic disorder caused by genetic or acquired partial deficiencies in the heme biosynthesis pathway. This results in accumulation of photoactive porphyrins, mainly uroporphyrins. Pseudoporphyria is a disorder caused by abnormal drug metabolites that accumulate as photoactive substances. PCT and pseudoporphyria clinically present with symptoms including photosensitivity, skin fragility, bullae, erosions, crusts, and scarring. Cutaneous symptoms exclusively involve sun-exposed skin.