Dry Skin

Dry face. Dry hands. Dry skin on your arms and legs despite moisturizing. Does this sound familiar? If it does, you might lack the protein filaggrin in your skin. Symptoms of filaggrin deficiency include dry spots and cracks in the skin, as well as dry and scaly skin on your arms and legs. These symptoms describe the condition ichthyosis vulgaris, also known as fish scale skin.

Filaggrin deficiency causes a damaged and sensitive skin barrier

If you lack filaggrin in your skin, frequent applications of traditional moisturizing cream may not be effective in soothing dry skin. When there are low levels of filaggrin in the skin, there are fewer water-binding amino acids, so the skin becomes dry and cracked.

What is filaggrin?

Filaggrin is a protein that occurs naturally in the skin. Filaggrin is a vital component of the skin’s natural ecosystem because it breaks down to amino acids, which are essential natural moisturizing factors (NMFs) that help keep the skin properly hydrated. Without NMFs, the skin barrier dries out and cracks. This can lead to itch and leave the skin more prone to infection as it becomes easier for bacteria, such as Staphylococcus, to enter the skin.

All babies are born without the filaggrin protein. Shortly after birth, since the child is no longer surrounded by water, the body starts to produce filaggrin, which is vital for the skin’s natural ability to bind water. 

Causes of filaggrin deficiency

There are two main causes of lack of filaggrin in skin.

1. Chronic, genetic filaggrin deficiency. This condition affects up to 9% of the population.
2. 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.

Both cases can result in fragile and sensitive skin that needs extra treatment.

1. Thyssen JP, Kezic S. Causes of epidermal filaggrin reduction and their role in the pathogenesis of atopic dermatitis. J Allergy Clin Immunol. 2014;134(4):792-799.

Atopic dermatitis (eczema): 50% have filaggrin deficiency

Studies show that up to 50% of people affected by 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 first develops atopic dermatitis, it becomes more difficult to ‘grow out’ of the condition if they have filaggrin deficienct skin, compared to children with normal levels of filaggrin. Filaggrin deficiency also increases the risk of developing severe eczema.

Sjögren’s syndrome can cause dry skin

Sjögren’s syndrome is distinguished by 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 most people with the condition experience dry skin and ichthyosis vulgaris (fish scale skin) on their legs. This is likely because the mild chronic skin inflammation associated with Sjögren’s syndrome, due to overactivity of the immune system, reduces filaggrin production.