What Is Erythropoietic Protoporphyria?

Erythropoietic protoporphyrinosis is a hereditary skin disease caused by low ferrochelase activity and elevated protoporphyrinogen IV levels.

Basic Information

English name

erythropoietic protoporphyria

Visiting department

dermatology

Multiple groups

3 to 5 years old

Common causes

Autosomal dominant inheritance

Common symptoms

Burning sensation, acupuncture, or itching, pimples and blisters

Etiology of Erythropoietic Protoporphyrin Disease

The disease belongs to autosomal dominant inheritance, and its genetic gene has a variable penetrance, which is related to suppressor genes and environmental factors.

Clinical manifestations of erythropoietic protoporphyria

Most of the onset of the disease occurs within the age of 3 to 5 years old, and there are also those who do not have it until adolescence. More men than women, summer is heavy and winter is light. It is characterized by a local burning sensation, acupuncture, or itching 5 to 30 minutes after sun exposure. After a few hours, erythema and high degree of edema appear on the skin. In severe cases, pimples, blister, purpura, and blood blister are similar to acne vesicular disease. Subsequently, erosions, thick black palate, or strange linear crusts were formed. The recurrence of the rash caused the patient's face to undergo wind-frost-like changes, and linear atrophic scars were visible on exposed areas such as the face and back of the hand. The rash recurs throughout life. Patients generally have no systemic symptoms. Few have discomfort such as chills, fever, and nausea.

Examination for erythropoietic protoporphyria

Blood test

Protoporphyrin in plasma, erythrocytes, and feces increased. A few patients had an increase in fecal porphyrin. Porphyrin in urine was normal. Serum iron levels decreased, iron binding capacity increased, hemoglobin and blood cell volume decreased, and liver function abnormalities may occur. Red blood cells emit short-term (10-15 seconds) orange-red fluorescence under an iodine-tungsten quartz lamp.

2. Histopathology

In the skin lesions and exposed areas, the epidermis is mostly normal. A large amount of amorphous material is deposited in and around the vascular wall of the dermal papilla. The nipples can widen, the epidermis becomes narrow and long, the vascular wall thickens, and the endothelial cells swell. Occlusion of the lumen can occur. When the bullae occurred, it was located under the epidermis, the basement membrane band thickened, and PAS staining was positive.

3. Direct immunofluorescence

Immunoglobulin deposits, mainly immunoglobulin G (IgG), can be seen around the blood vessels in the dermal papillary layer, and there is also a slight deposit at the epidermal dermal junction. Observation of the thickening of the vascular basement membrane by transmission electron microscopy, no structural matter was deposited in multiple layers, and fine fibrils of medium electron density filled the vessel wall and surrounded the vessel.

Diagnosis of erythropoietic protoporphyria

The diagnosis of this disease is not difficult, mainly based on the characteristic clinical manifestations and the increase of protoporphyrin.

Differential diagnosis of erythropoietic protoporphyria

Erythrocytes have transient fluorescence that can be distinguished from hepatic porphyrins. In addition, it should be distinguished from congenital erythropoietic porphyria, pleomorphic solar rash, and solar urticaria.

Erythropoietic protoporphyrinosis complications

When protoporphyrin is formed too much beyond the maximum excretion capacity of the liver, it is deposited on the liver and causes damage to hepatocytes, showing symptoms of hepatomegaly, jaundice, abdominal pain, portal hypertension, and bleeding from esophageal vein rupture. Bile contains a large amount of protoporphyrin, which can be associated with cholecystitis and gallstones.

Erythropoietic protoporphyria treatment

Beta carotene is effective for this disease. Although the levels of protoporphyrin in plasma and erythrocytes did not change significantly after treatment, the tolerance to sunlight increased. Therefore, -carotene is believed to quench active oxygen radicals in the excited state, block photosensitivity or have the same maximum absorption as porphyrin The spectrum acts as a barrier. It is generally taken orally, and yellowing of the skin may occur after taking the drug without other adverse reactions. In addition, you can also try to increase the tolerance to light by narrow-band medium-wave ultraviolet (NB-UVB) irradiation. Symptomatic treatment of patients with liver damage cholecystitis and cholelithiasis.