delayed cutaneous porphyria
Introduction
Introduction to delayed skin porphyria Delayed porphyria porphyria (porphyriacutaneatarda. PCT) is both an inherited disease and an acquired disease. Named by WaldEnsnstrom for the first time in 1937, it is characterized by photosensitive dermatitis, facial hairiness, skin scarring, roughness, thickening, and pigmentation. There are no neuropathic porphyria, and some patients have liver damage. It is generally believed that the disease is caused by a combination of various acquired factors on the basis of a hereditary background. basic knowledge The proportion of sickness: 0.004% - 0.006% Susceptible people: no specific people Mode of infection: non-infectious Complications: malnutrition cataract diabetes
Cause
The cause of delayed skin porphyria
Genetic factors (30%):
Lack of uroporphyrinogen decarboxylase, its gene is located on chromosome 1q34, and the lack of uroporphyrinogen decarboxylase in liver tissue is found in all patients with delayed-onset porphyria, but genetic factors are only seen in familial and a few sporadic patients. It is autosomal dominant.
Iron deposition (30%):
Liver iron deposition can be seen in more than 80% of patients with delayed skin porphyria, iron deposition is moderate, use blood to reduce iron deposition, or trial use of iron treatment can make patients with clinical and biochemical relief, stop bleeding or use Iron can relieve the recurrence of patients, indicating that iron is closely related to the disease.
Prevention
Delayed skin porphyria prevention
There are no effective preventive measures for this disease. Early detection, early diagnosis and early treatment are the key to the prevention and treatment of this disease. Once the disease occurs, it should be actively treated to prevent the occurrence of complications and remove the harmful factors to the liver, especially alcohol. Avoid using drugs that are harmful to the liver, such as barbiturates, estrogens, hydroxy chemicals, irons, etc. Avoid sun exposure and trauma, apply sunscreen, can play a preventive role.
Complication
Delayed porphyria complication Complications malnutrition cataract diabetes
A small number of cases are deformed and disfigured due to scars. Others include nail stripping, atrophic calcification of the auricle, cataract, and scleral ulcer. 15% to 20% of patients with this disease have diabetes, and some are accompanied by cirrhosis.
Symptom
Symptoms of delayed skin porphyria common symptoms crusting jaundice papule itching
Patients often develop early onset, and most of the PCTs that occurred before the age of 20 belong to this type. Patients have mild to moderate photosensitivity dermatitis, especially in summer. The site of the disease is mostly exposed in the hands, face, neck, upper chest, calves and feet. The rash is mostly erythema, and it can also be expressed as solar urticaria, consciously itching or burning. Chronic damage is blisters, bullae, erosion, crusting and shallow sputum. The blister has a diameter of 2 to 30 mm, round or irregular shape, and the blister is more clarified or bloody. Skin fragility increases in the hands and wrists, and minor trauma can lead to multiple painless red erosions. Scratch the nails to scrape the affected skin, called the Dean sign. About 10% of patients have scleroderma-like lesions, which are more common in the neck, chest and face, but can also occur in non-exposed areas. Clinical and histopathology are difficult to distinguish from scleroderma.
Examine
Examination of delayed skin porphyria
1. Peripheral blood: Most patients have no anemia, blood is normal, and a small number of patients may have mild erythrocytosis.
2. Urine examination: The main test in the laboratory is that the urine contains more urinary porphyrin and 7-carboxy porphyrin, which makes the urine turn red, and the excretion of ALA and bilirubin in urine does not increase.
3. Fecal examination: The fecal porphyrin and 7-carboxy porphyrin in the feces increased significantly, and the protoporphyrin increased normally or moderately.
4. Liver function examination: Because patients often have liver disease, urinary biliary tract may be positive, serum transaminase may increase, sulphonium bromide sodium excretion is often lower than normal, erythrocyte and intrahepatic uroporphyrinogen decarboxylase activity in hereditary patients The decrease is only about 50% of that of normal people. The activity of this enzyme in the liver of acquired patients also drops to about 50% of normal people, but the enzyme is normal in red blood cells.
Diagnosis
Diagnosis and diagnosis of delayed skin porphyria
diagnosis
According to skin delayed photosensitivity, skin damage, red urine, laboratory examination of urine urinary porphyrin discharge increased a lot, can make a diagnosis, diagnosis should pay attention to the cause of porphyria, such as drinking, taking estrogen history, chemical poisons The history of exposure, patients over the age of 60 should pay attention to the presence or absence of liver tumors.
Differential diagnosis
Should pay attention to the exception of pleomorphic sun rash, vaccinia-like vesicular disease, niacin deficiency, scleroderma, drug photoreceptive dermatitis, various bullous diseases, impetigo, etc., hemodialysis may cause false late onset Morphological disease, there may be a rash similar to this disease but urine, feces, blood porphyrin determination can be identified.
