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Ichthyosis
Make it clearer
The ichthyoses are skin diseases marked by faulty cornification, the process by which skin cells harden as they move upward until they form the horny layer, the dead, protective outer layer. Some ichthyoses are inherited and others are acquired later.
In ichthyosis vulgaris the problem has a name. Mutations in the FLG gene produce a defective form of filaggrin, the protein that builds the cornified envelope, the rigid shell around each cell of that layer. The horny layer is a brick wall held together by mortar: without the mortar, the wall cracks and lets things through.
And a cracked wall fails in both directions. Outward, too much water escapes through the epidermis, the surface layer of the skin. Inward, microorganisms and allergens, the substances that trigger allergic reactions, get in more easily.
In brief
The ichthyoses are disorders of cornification, the process that forms the skin's horny layer, and they are classified as inherited or acquired.
The core problem is a broken epidermal barrier: in ichthyosis vulgaris, mutations in the FLG gene make the filaggrin of the cornified envelope defective.
The horny layer is a brick wall held together by mortar: without the mortar, the wall cracks and lets things through.
With the barrier broken, water is lost through the epidermis and allergens and microorganisms get in more easily.
Sources (1)
- National Center for Biotechnology Information, StatPearls PublishingHereditary and Acquired Ichthyosis Vulgaris, StatPearlsPublished
This page explains the topic in general terms; it does not tell anyone what treatment to follow.
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