What causes eczema?

Eczema is a very common skin condition and is often associated with allergies. Food allergies, allergic rhinitis (both hayfever or year-round rhinitis), asthma and eczema belong to a family of conditions called Atopy. Under normal circumstances, common allergens e.g. house dust mite, pollen, foods, are accepted as ‘friend‘ by the immune system. However, atopic individuals mount an immune response to attack these otherwise ‘accepted’ allergens – therefore causing the symptoms we see. 

It is likely that the cause of eczema is multifactorial: genetics (see filaggrin below), environmental (e.g. food allergens, pollen), but one thing is for sure – the immune system is the cause of the symptoms experienced by eczema patients. The itchiness/rash that we see is the end result of a malfunctioning immune system and so a lot of eczema treatments have been designed to dampen the immune system:

  • at the mildest level, we have steroid creams (e.g. cortisone) or topical immune modulators like pimecrolimus which dampens inflammation in the skin. ( *Eucrisa has just been approved by the FDA as a topical treatment for children above age 2 yrs and adults with mild to moderate eczema – it works by blocking the inflammatory process i.e. reduces inflammation in the skin)
  • Next, we have oral immunosuppressants e.g. ciclosporin and oral steroids (a lot stronger than topical steroids) I used to prescribe to patients with more severe symptoms that did not respond to topical therapy. 
  • biological agents are made up of antibodies e.g. Dupilumab – these antibodies bind to and block the proteins involved in the inflammatory process and therefore dampen down inflammation in the skin and making eczema better. 

As you can see, all of the treatment modalities focus on dampening down inflammation in the skin. But we have nothing which tackles the root cause to stop the inflammation happening in the first place…. because we still don’t really know why the immune system causes inflammation in the skin in the first place. 

We have found many pieces of the puzzle, but there are still many missing links. Genes definitely play an important role – we know that mutations in a gene that makes Filaggrin (a protein found in the skin responsible for maintaining skin barrier) is associated with the development of eczema.

What is Filaggrin?

Imagine your skin as a brick wall. Each skin cell is a brick. The skin is made up of multiple layers of skin cells stacked on top of each other, just like a brick wall. Filaggrin is part of the ‘cement’ which holds the bricks (the skin cells) together. Without cement, a brick wall is fragile and falls apart easily.


In patients with eczema, the ‘cement’ is defective or absent. Like this brick wall here. Moisture that would normally be held within the skin evaporates easily through the cracks – leading to dry skin, and also the bugs and environmental allergens which would normally be kept outside can now enter easily, leading to an increased risk of allergies, triggering off irritation, inflammation and infections.
Healthy skin should look like this red brick wall here. The gaps in between each brick is filled with cement, so there is no moisture loss, or penetration of allergens or bacteria











Environmental factors

There are many environmental factors which act as ‘triggers’ for eczema patients, most commonly: stress, foods, change in weather. We really don’t have a very clear understanding of how environmental factors are causing the development of eczema yet… but from a personal perspective, I believe that if you have a healthy gut the skin also improves.

Thomas had severe eczema from the age of 5 weeks. His eczema was so widespread and awful that he was photographed for the hospital archive to illustrate ‘severe eczema’!!! It is anecdotal, but I saw how, as Thomas’s gut recovered, his eczema improved too, and now he has grown out of his eczema. It may have been coincidence, but I believe that gut health leads to a healthy immune system and reduced inflammation – since eczema is caused by a malfunctioning immune system, this will turn help eczema. Instead of dampening down the immune system with steroid creams and oral immunosuppressants, you may be able to do this with foods and lifestyle measures.

Just my thoughts, but I will be sharing how I healed Thomas’ gut later if you are interested…

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