Why does skin look like fish scales?

If you find that your skin looks like fish scales, it is ichthyosis, a very common skin disease. It is highly hereditary. 70% of ichthyosis are inherited. Especially in winter, the dry skin will be more serious, and it will become more serious with age.

Four types of ichthyosis

1. Ichthyosis vulgaris: It mainly manifests as dry brown diamond-shaped or polygonal scales on the extensor side of the limbs and trunk. There are often obvious follicular keratotic papules on the extensor side of the upper arms and thighs. The palms and toes are affected, and the incidence rate is very high. The keratotic scales are caused by the accumulation of several layers of keratinocytes that do not fall off. They usually appear several months after birth and are most severe around 5 years old. The symptoms may be alleviated after puberty, but the condition worsens with age and improper treatment.

2. Sex-linked hidden ichthyosis: It may occur after birth or in infancy. The skin lesions are large and obvious, and are yellow-brown or dirty black large scales. The skin is dry and rough, often spread all over the body, and the armpits, elbows and other parts may also be affected; the abdomen and back are particularly serious. If the face is affected, it is limited to the front of the ears and the sides of the face. Keratosis of hair follicles generally does not occur, and the skin on the palms and toes is normal. The skin lesions do not decrease with age, and sometimes they increase in weight.

3. Epidermolytic hyperkeratotic ichthyosis, also known as bullous congenital ichthyosis-like erythroderma, is an autosomal dominant genetic disease with a high abnormality rate. It is rare in clinical practice. Generalized and localized damage may occur after birth or a few months after birth. Generalized patients are born with a thick layer of armor-like scales all over the body, which fall off immediately after birth, and generalized flushing and scaling appear. Removal of the scales reveals a smooth face, and the erythema may gradually disappear. Thicker wart-like scales may recur. Localized patients may have thicker ichthyose-like keratin flakes only on the flexor side of the limbs and the wrinkled walls.

4. Lamellar ichthyosis is an autosomal recessive trait. The whole body is tightly wrapped with a layer of extensive cotton wool-like membrane after birth, which often causes eversion of the eyelids and lips. The membrane falls off after a few days, and the skin becomes extensively diffusely flushed, with large grayish white or grayish brown polygonal or diamond-shaped scales, fixed in the center and free at the edges. It often occurs symmetrically all over the body, and is more obvious in the flexor side of the limbs, elbows, axillae, and vulva. The palms and toes are excessively keratinized, and the nails and hair grow excessively. The disease course is slow and can exist for life. The erythroderma can be alleviated in adulthood, but the scales still exist.