Porphyria Non-Acute

Non-acute porphyrias are a group of rare inherited conditions that primarily affect the skin, causing it to become sensitive to sunlight and leading to symptoms like pain, blistering, and scarring in sun-exposed areas.

Table of contents

• What is Non-Acute Porphyria?
• Types of Non-Acute Porphyria
• Causes and How It Develops
• Symptoms and How They Affect Daily Life
• Diagnosis
• Treatment and Management
• Diet and Nutrition

What is Non-Acute Porphyria?

Non-acute porphyrias are a group of rare disorders that affect how your body makes a substance called heme, which is a vital part of hemoglobin in your blood. Hemoglobin carries oxygen to all parts of your body^[1]. When one of the eight enzymes needed to produce heme doesn’t work properly, certain chemicals called porphyrins build up in your body^[2].

Unlike acute porphyrias, which cause sudden attacks of severe abdominal pain and nervous system symptoms, non-acute porphyrias mainly affect the skin^[5]. The buildup of porphyrins in these conditions occurs without causing the characteristic abdominal pain and neurological features seen in acute forms^[5]. These porphyrins react to light, which is why sun-exposed areas of the body are affected, producing various skin problems^[6].

Types of Non-Acute Porphyria

There are several types of non-acute porphyrias, each with its own pattern of symptoms^[8]:

• Porphyria Cutanea Tarda (PCT) is the most common type of porphyria overall. It causes blistering and skin fragility on sun-exposed areas, usually appearing in adulthood^[3][8].
• Erythropoietic Protoporphyria (EPP) and X-Linked Protoporphyria (XLP) cause severe pain, burning, and swelling on sun-exposed skin, usually without blistering. Symptoms typically start in infancy or childhood^[3][8].
• Congenital Erythropoietic Porphyria (CEP) is very rare and causes severe blistering on sun-exposed areas that can lead to infections and scarring. Symptoms generally start at birth or in early childhood^[3][8].
• Hepatoerythropoietic Porphyria (HEP) is an extremely rare form of porphyria^[8].

Causes and How It Develops

Most non-acute porphyrias are inherited, meaning they are passed down from parents to children through gene changes^[2]. These gene changes affect the enzymes needed to produce heme. When these enzymes don’t work properly, porphyrins build up in the body^[1].

However, Porphyria Cutanea Tarda is different. While some cases are inherited, most cases of PCT are acquired and require triggers to develop. Even though there may be a genetic tendency, other factors such as liver infection, liver disease, excess iron, or alcohol use are usually needed for the condition to appear^[3][7].

In non-acute porphyrias, the excess porphyrins build up in different places depending on the type. In some forms, the porphyrins come mainly from the bone marrow, while in others they come from the liver^[3][6]. The bone marrow pathway that produces heme is much less sensitive to changes in diet and energy intake compared to the liver pathway^[3].

Symptoms and How They Affect Daily Life

The main symptoms of non-acute porphyrias involve the skin. When porphyrins that have built up in the body reach the skin, they react to sunlight, causing problems in sun-exposed areas^[6].

Different types of non-acute porphyrias cause different skin symptoms. Some cause blistering skin problems, while others cause pain and burning without blisters^[8].

For blistering types like PCT and CEP, the skin becomes fragile and blisters easily after sun exposure. The blisters can lead to scarring and changes in skin color^[1][3].

For non-blistering types like EPP and XLP, people experience severe pain, stinging, and burning on sun-exposed areas of skin. The pain can be accompanied by swelling and redness, and these symptoms typically last for several days^[3][6].

These skin problems can significantly affect daily life, limiting outdoor activities and requiring constant protection from sunlight^[1].

Diagnosis

Diagnosing non-acute porphyrias requires specific laboratory tests. The correct tests depend on which type of porphyria the doctor suspects^[4].

For most cutaneous porphyrias, doctors measure porphyrin levels in blood plasma using a special technique called fluorescence emission spectroscopy^[4]. Urine tests to measure total porphyrins are also commonly used for diagnosing conditions like PCT and CEP^[3].

For protoporphyrias like EPP and XLP, the key test measures porphyrin levels in red blood cells^[3][4].

Genetic testing can confirm the diagnosis by identifying the specific gene change causing the porphyria. Once a gene change is found in one family member, testing can be done on other relatives to see if they have inherited the condition^[13].

Treatment and Management

While there is no cure for porphyria, treatments are available for managing symptoms^[11][13].

The most important part of managing non-acute porphyrias is avoiding triggers, especially sun exposure. When outdoors, people should wear protective clothing and use sunscreen with blocking ingredients like zinc oxide or titanium dioxide. For short sun exposure, an SPF of at least 30 is recommended, while longer outdoor periods require SPF 50^[13].

For Porphyria Cutanea Tarda, treatment focuses on reducing iron levels in the body and avoiding alcohol and iron supplements^[3]. Regular removal of small amounts of blood can help reduce iron stores and improve symptoms.

For Erythropoietic Protoporphyria, a medication called SCENESSE (afamelanotide) is available in some countries. This treatment helps increase tolerance to sun and light in adults with a confirmed diagnosis of EPP^[11].

People with EPP should ensure they get enough iron in their diet to prevent iron deficiency, which can make the condition worse. However, iron supplements should only be taken if tests show that iron stores are low^[3].

Diet and Nutrition

For non-acute porphyrias, dietary recommendations are quite different from those for acute porphyrias^[3].

A balanced diet that provides all essential nutrients is important for everyone with non-acute porphyria. Beyond this general advice, only a few specific dietary recommendations apply^[3].

For Porphyria Cutanea Tarda, the most important dietary considerations are avoiding alcohol and not taking iron supplements. Restriction of dietary iron from food is usually not necessary^[3].

For Erythropoietic Protoporphyria, it’s important to maintain adequate iron intake through diet to prevent iron deficiency. The bone marrow, where the excess porphyrins come from in this condition, is not highly sensitive to changes in carbohydrate and energy intake like the liver is in acute porphyrias^[3].

For Congenital Erythropoietic Porphyria, diet does not appear to play a specific role in disease activity. However, because patients with this condition may be severely ill, ensuring adequate nutrition is important to prevent deficiencies that could contribute to anemia and other problems^[3].