Dry facial skin, dry hands, dry skin on your arms and legs despite moisturizing the skin. Does that sound familiar? If so, you might lack the protein filaggrin in your skin. Filaggrin deficiency can cause dry spots and skin fissures as well as dry and scaly skin on your legs and arms. This condition is called ichthyosis vulgaris, also known as fish scale skin.
Filaggrin is a protein that occurs naturally in the skin. Filaggrin is a vital component of a healthy skin ecosystem because it is broken down to amino acids which are essential natural moisturizing factors (NMFs) that help keep the skin properly hydrated. Without these NMFs, the skin barrier breaks. This makes your skin itchy, dry, and prone to infections and allows unfriendly bacteria to engraft onto the skin.
If you lack filaggrin in your skin, you can apply traditional moisturizing cream to your dry skin over and over with only little fundamental effect. Filaggrin degrades into amino acids which bind water in the skin. So with low levels of filaggrin, your skin becomes -dry and cracked.
There are two main causes of lack of filaggrin in skin. Firstly, filaggrin deficiency can be a chronic condition caused by a genetic defect which affects up to 9% of the population. Secondly, skin inflammation from e.g. atopic dermatitis or psoriasis can cause a decrease in the natural production of filaggrin and the enzyme that breaks filaggrin down to amino acids.
In both cases, you will have a fragile and sensitive skin that requires extra care.
Up to 50% of people suffering from atopic dermatitis have filaggrin deficiency. Environmental factors also play a role in the development of atopic dermatitis but having filaggrin deficiency increases the risk.
If a child has developed atopic dermatitis, it is harder for it to ‘outgrow’ its eczema if it has filaggrin deficiency compared to children with normal filaggrin levels in their skin. Filaggrin deficiency also increases the risk of developing severe eczema.
Sjögren’s syndrome is a chronic inflammation that involves primarily the exocrine glands in the body (i.e. glands that produce fluids). The most common symptoms of Sjögren’s syndrome are dry eyes and dry mouth, but 50% of all people with Sjögren’s syndrome develop dry skin and ichthyosis vulgaris (fish scale skin) on their legs. This is probably because Sjögren’s syndrome is accompanied by a low-grade chronic inflammation of the skin, which occurs because the immune system is overactive, and this chronic inflammation of the skin reduces filaggrin production.