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Ichthyosis Vulgaris
Introduction
Ichthyosis Vulgaris is sometimes called fish scale disease or fishskin disease, ichthyosis vulgaris is an inherited skin disorder that causes dead skin cells to accumulate in thick, dry scales on the skin's surface. These scales can be present at birth, but usually first appear in early childhood. Sometimes ichthyosis vulgaris disappears entirely for most of the adult years, only to return later.
Though most cases are mild, some cases of ichthyosis vulgaris are severe. Since there is no cure, treatments focus on controlling the signs and symptoms.
Signs and Symptoms
Ichthyosis vulgaris is characterized by severely dry, scaly skin. The scales are small, polygonal in shape and range in color from white to dirty gray to brown. People with darker skin tend to have darker colored scales.
The scales usually appear on the elbows and lower legs and may be especially thick and dark over the shins. Ichthyosis may also cause scalp flaking and deep, painful fissures in the palms and soles. Though most cases of ichthyosis are mild, some can be severe.
Symptoms usually worsen or are more pronounced in cold, dry environments and tend to improve or even resolve in warm, humid environments.
Other less common forms of ichthyosis include:
- Lamellar ichthyosis. This severe form of the disease is present at birth and lasts throughout life. Infants with lamellar ichthyosis are born encased in a filmy membrane that's shed after 10 to 14 days, revealing skin that's covered in scales. The scales can range from fine and white to thick and dark and generally occur over the entire body, although they may be larger on the legs. Lamellar ichthyosis can be extremely disfiguring and may cause great psychological suffering for children and adults with the disease.
- X-linked ichthyosis. Starting soon after birth, this type of ichthyosis occurs only in males. The noticeable, dirty-brown scales that characterize this skin disease are most pronounced on the back of the neck, arms and behind the knees. Symptoms generally don't improve with age.
- Epidermolytic hyperkeratosis. This extremely rare form of ichthyosis is usually present at birth and begins with blistering skin. In time, the skin peels away in large sheets and becomes rough or wart-looking. It's most pronounced on the knees, elbows, wrists and other flexural areas.
Causes
The skin is an endlessly renewable organ. New skin cells at the base of the epidermis push toward the surface of the skin, where they eventually shrink, flatten and die. These dead skin cells flake off every day and are continuously replaced by more cells.
Ichthyosis, however, disrupts this pattern. It occurs when the production of skin cells is too fast or the skin's natural shedding process is too slow. This causes dead skin cells to collect into thick flakes that stick to the outer surface of skin. These thick flakes can resemble fish scales.
Most often, ichthyosis is inherited in an autosomal dominant pattern, which means that a child has to inherit only one copy of the affected gene to develop the disease. Children with the inherited form of the disorder usually have normal skin at birth but develop scaling and roughness in the first few years of life. At times, ichthyosis vulgaris may disappear during the adult years, only to return later.
Ichthyosis not caused by genetics, referred to as acquired ichthyosis, is very rare. This type usually manifests in adulthood and is usually associated with other internal diseases, such as cancer, thyroid disease or chronic renal failure.
Treatment
There is no known cure for ichthyosis, so the goal of treatment is to manage the problem. In addition to home care, treatment can include prescription creams and ointments that contain alpha hydroxy acids, such as lactic acid and glycolic acid. These chemicals help control the scaling and increase skin moisture.
In severe cases, the doctor may prescribe retinoids — medications derived from vitamin A. They reduce the production of skin cells. Side effects from the medication may include eye and lip inflammation, bone spurs and hair loss, as well as birth defects if taken during pregnancy.
Information obtained from National Institute of Health