Epidermolytic hyperkeratosis

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Epidermolytic hyperkeratosis (EHK) is a rare genetic skin disorder characterized by blistering and thickening of the skin. It is a form of ichthyosis, a group of skin conditions that lead to dry, scaly skin. EHK is also known as bullous congenital ichthyosiform erythroderma (BCIE).

Presentation

EHK typically presents at birth or shortly thereafter. Newborns with EHK often have widespread erythroderma (red skin) and blistering. As the child grows, the blistering tends to decrease, but the skin becomes thickened and scaly, particularly on the palms and soles. The thickened skin may have a corrugated appearance and can be prone to infections.

Genetics

EHK is usually inherited in an autosomal dominant manner, meaning only one copy of the mutated gene is necessary for the condition to occur. The disorder is primarily caused by mutations in the KRT1 and KRT10 genes, which encode the proteins keratin 1 and keratin 10, respectively. These proteins are essential for the structural integrity of the skin.

Pathophysiology

The mutations in the KRT1 and KRT10 genes lead to the production of abnormal keratin proteins, which disrupt the normal structure and function of the epidermis. This disruption causes the skin cells to become fragile and easily damaged, leading to blistering. Over time, the skin responds by producing excess keratin, resulting in thickened, scaly skin.

Diagnosis

Diagnosis of EHK is typically based on clinical examination and family history. A skin biopsy may be performed to observe the characteristic histological features, such as epidermal hyperkeratosis and vacuolar degeneration of the upper epidermis. Genetic testing can confirm the diagnosis by identifying mutations in the KRT1 or KRT10 genes.

Treatment

There is no cure for EHK, but treatment focuses on managing symptoms and preventing complications. Emollients and keratolytic agents can help to soften and remove the thickened skin. Topical and systemic retinoids may be prescribed to reduce scaling. Infections should be treated promptly with appropriate antibiotics.

Prognosis

The prognosis for individuals with EHK varies. While the condition is chronic and requires ongoing management, many people with EHK lead relatively normal lives. The severity of symptoms can vary widely, even among affected members of the same family.

See also

• Ichthyosis
• Erythroderma
• Keratin
• Genetic disorders

External links

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