Lamellar ichthyosis

Lamellar ichthyosis (LI), also known as lamellar ichthyosis type 1 or non-bullous congenital ichthyosiform erythroderma (though this term more broadly encompasses a spectrum), is a rare autosomal recessive disorder of keratinization that primarily affects the skin. It belongs to the group of autosomal recessive congenital ichthyoses (ARCI). Affected infants are typically born encased in a tight, shiny membrane called a collodion membrane, which cracks and sheds within the first few weeks of life. After shedding, the skin develops generalized, large, dark, plate-like (lamellar) scales covering the entire body surface. The scales are typically brown or gray-brown and are most prominent on the legs, arms, and trunk. Key clinical features include ectropion (outward turning of the eyelids), eclabium (outward turning of the lips), scarring alopecia of the scalp, and hypoplasia of the nasal and auricular cartilage. Palms and soles may show thickened skin (palmoplantar keratoderma). Patients frequently experience heat intolerance due to impaired sweating, which can lead to hyperthermia, particularly in warm environments. Nail dystrophy and reduced mobility of joints due to tight skin may also occur. The condition is caused by mutations in several genes involved in lipid metabolism and skin barrier function, with TGM1 (transglutaminase 1) being the most commonly implicated gene, accounting for approximately 30-50% of cases. Other causative genes include ABCA12, ALOX12B, ALOXE3, CYP4F22, NIPAL4, LIPN, and CERS3. There is currently no cure for lamellar ichthyosis. Treatment is primarily symptomatic and supportive, focusing on intensive skin hydration with emollients and keratolytic agents such as urea-containing creams, lactic acid, or salicylic acid to reduce scaling. Oral retinoids (such as acitretin) may be used in severe cases to reduce scale thickness, though long-term use requires monitoring for side effects. Management of ectropion with lubricating eye drops is important to prevent corneal damage. Neonatal care of collodion babies requires a humidified incubator environment, careful monitoring for fluid and electrolyte imbalances, temperature regulation, and infection prevention. Genetic counseling is recommended for affected families.

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