Introduction
X-linked ichthyosisAlso known as ichthyosis nigricans, X-linked recessive ichthyosis (recessive X-linked ichthyosis).
Cause
(1) Causes of the disease
In the 1860s, X-linked recessive ichthyosis was distinguished from other ichthyosis by clinical manifestations. Later, the disease was found to be associated with steroid sulfatase abnormalities. Steroid sulfatase hydrolyzes sulfates, including cholesterol sulfate and sulfate steroids. After the fetal sulphate adrenaline desulfurization, it becomes estrogen and is excreted from the mother's urine. The lack of steroid sulfatase in the fetal placenta can lead to a decrease in estrogen in the mother's urine, and in some women, it can also cause labor initiation and labor barriers. In males with ichthyosis vulgaris, steroid sulfatase activity is reduced or absent in many tissues, including epidermis, stratum corneum, white blood cells, and cultured fibroblasts. In addition, the enzyme substrate, cholesterol sulfate, can accumulate in the scales. The level of leukocyte steroid sulfatase in female carriers is between normal individuals and male patients.
In men, the incidence of squamous ichthyosis is about 1:2000 ~ 1:6000, about half of adult male patients may have comma-like corneal opacity, but does not affect vision, but also in female carriers. The incidence of cryptorchidism and testicular cancer increases in male patients. Serum, epidermis, and squamous cholesterol levels are elevated, and gel electrophoresis shows an increase in β-lipoprotein (low-density lipoprotein), which can be used as one of the diagnostic features. When serum cholesterol cholesterol levels are increased from normal 80-200 μg/dl to 2000-9000 μg/dl, the diagnosis can often be determined.
(two) pathogenesis
The steroid sulfatase gene is located on the short-armed two-zone, two-band, and three-subbands of the X chromosome (Xp22.3), and is deficient in approximately 80% of patients. If the sulfatase deficiency is adjacent, punctate cartilage dysplasia and X-linked ichthyosis overlap syndrome may occur.
In the epidermis, steroid sulfatase catalyzes the hydrolysis of cholesterol sulfate. The lack of steroid sulfatase in X-linked ichthyosis patients indicates that hydrolysis of sulphuric acid cholesterol is very important for normal desquamation. In mice, topical sulphuric acid cholesterol can induce abnormalities in desquamation, further supporting the hydrolysis of cholesterol by cholesterol to play a role in keratinocyte dissociation.
However, some studies have found that some patients have normal steroid sulfatase activity without corneal opacity, which shows the genetic heterogeneity of X-linked ichthyosis. Therefore, male ichthyosis patients with normal steroid sulfatase levels cannot exclude X-linked recessive ichthyosis.
symptom
Almost all seen in men. Occurred at birth or shortly after birth. Large and significant scales are often seen on the extremities, face, neck, trunk, and buttocks, with the neck, face, and trunk being the heaviest. Individual cases or severe cases can affect the elbow fossa, underarms and armpits. The palmar appearance is normal or slightly thickened, and the scales are often brown and sticky. Female carriers have mild scales in front of their arms and ankles. Eye slit lamp examination, some patients can see obvious posterior corneal wall or elastic layer opacity. Male patients may have cryptorchidism and testicular cancer. Skin lesions do not decrease with age.
According to the clinical manifestations, the characteristics of skin lesions and histopathological features can be diagnosed.
diagnosis
1. Acanthosis is more common in adults, and more invasive skin wrinkles and physiologic pigments such as axillary fossa, groin and vulva. The skin lesions are brown patches. Histopathological findings showed papillary-like proliferation, often complicated by visceral cancer.
2. Congenital ichthyosis-like erythroderma appears ichthyosis-like damage on the basis of diffuse flushing of the skin, with the body flexing side and increasing in summer.
3. squamous follicular keratosis There are black spots in the center of the scales, consistent with the hair follicles, visible central fixation, free lobular scaly around, more common in the waist, buttocks and ventral side.
complication
Male patients may have cryptorchidism and testicular cancer.
treatment
(a) treatment
Avoid close relatives to get married, prevent excessive dryness of the skin, and disable alkaline heavy soaps and irritating drugs. Oral administration of large doses of vitamin A or vitamin A acid has a certain effect. Topical 10% urea ointment, 0.1% vitamin A acid ointment, etc. can reduce skin lesions. The condition can be alleviated in a warm, humid climate.
Chinese medicine law:
Governing Law: spleen and nourishing skin.
Recipe: nourishing and moisturizing drink. 10g of red peony root, 15g of medlar, 10g of angelica, 15g of salvia miltiorrhiza, 15g of spatholobus suberectus, 10g of safflower, 10g of Codonopsis pilosula, 10g of Radix Astragali, 10g of asparagus, 10g of asparagus, 10g of turf, 10g of radix, 10g of radix, and 10g of dried tangerine peel. According to the situation, you can also choose to take ginseng Jianpi pill, ginseng spleen pill, moisturizing pill, Bazhen pill, Qin 艽 pill and so on.
Topical medicine: You can mix the outer sputum with big maple oil, licorice oil, egg butter and other ingredients.
(two) prognosis
Male patients may have cryptorchidism and testicular cancer. Skin lesions do not decrease with age.
prevention
Avoid close relatives to get married, prevent excessive dryness of the skin, and disable alkaline heavy soaps and irritating drugs.
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