Editing Porphyria (section)

===Chronic porphyrias===
The non-acute porphyrias are X-linked dominant protoporphyria (XLDPP), congenital [[erythropoietic porphyria]] (CEP), [[porphyria cutanea tarda]] (PCT), and [[erythropoietic protoporphyria]] (EPP). None of these is associated with acute attacks: their primary manifestation is with skin disease. For this reason, these four porphyrias—along with two acute porphyrias, VP and HCP, that may also involve skin manifestations—are sometimes called cutaneous porphyrias.

Skin disease is encountered where excess porphyrins accumulate in the skin. Porphyrins are photoactive molecules, and exposure to light results in promotion of electrons to higher energy levels. When these return to the resting energy level or ground state, energy is released. This accounts for the property of fluorescence typical of the porphyrins. This causes local skin damage.

Two distinct patterns of skin disease are seen in porphyria:
* '''Immediate photosensitivity.''' This is typical of XLDPP and EPP. Following a variable period of [[Health effects of sunlight exposure|sun exposure]]—typically about 30 minutes—patients complain of severe pain, burning, and discomfort in exposed areas. Typically, the effects are not visible, though occasionally there may be some redness and swelling of the skin.
* '''Vesiculo-erosive skin disease.''' This—a reference to the characteristic [[blister]]ing (vesicles) and open sores (erosions) noted in patients—is the pattern seen in CEP, PCT, VP, and HCP. The changes are noted only in sun-exposed areas such as the face and back of the hands. Milder skin disease, such as that seen in VP and HCP, consists of increased skin fragility in exposed areas with a tendency to form blisters and erosions, particularly after minor knocks or scrapes. These heal slowly, often leaving small scars that may be lighter or darker than normal skin. More severe skin disease is sometimes seen in PCT, with prominent lesions, darkening of exposed skin such as the face, and [[hypertrichosis]]: abnormal hair growth on the face, particularly the cheeks. The most severe disease is seen in CEP and a rare variant of PCT known as [[hepatoerythropoietic porphyria]] (HEP); symptoms include severe shortening of digits, loss of skin appendages such as hair and nails, and severe scarring of the skin with progressive disappearance of ears, lips, and nose. Patients may also show deformed, discolored teeth or gum and eye abnormalities.