Barrier Function: Is your skin leaky?

Barriers are meant to protect us.

Your skin is a barrier to your body’s internal systems. It is there to keep your insides safe.

Your skin is one of your body’s first lines of defense. It keeps infectious agents, toxins, and other environmental agents on the outside of you, and prevents them from getting in.

It also keeps important things (like water) on the inside.

Take a close look at your skin. You might see some fine lines, folds, or wrinkles. There aren’t any holes there—at least not to the naked eye. But if you could examine your skin microscopically, you might find that there are gaps between the cells.

Skin As A Barrier

The cells on the surface of your skin are held together with proteins called tight junctions. Tight junctions regulate the permeability of your skin. They are important in maintaining your

skin’s function as a barrier.

Is Your Skin Permeable (a.k.a. is it leaking?)

When the function of tight junctions is diminished, gaps exist between the skin cells. The skin becomes permeable.

Do you have eczema? Skin permeability is associated with eczema (1).

Why Is It Leaking?

Immune cells can influence the skin integrity through the production of various mediators. Mast cells are masters of mediator release, so it should come as no surprise that MCAS can contribute to leaky skin.

It’s Not Just Your Skin That is Leaking

Here’s a brief look at other barrier tissue in your body that might be leaking:

• Lungs - Inflammatory lung diseases like asthma and chronic obstructive pulmonary disease (COPD) have increased permeability (2). These conditions are also known to have mast cell involvement. (3, 4)
  

• Gut - Permeability allows food particles, microbes, and waste products to pass through. Immune cells such as mast cells can trigger these junctions to open by releasing mediators such as tryptase (5), proteases and TNF-α (6).
  

• Blood brain barrier - Mast cells are involved in the permeability of the blood brain barrier in brain injury (7).
  

A 2020 study in the Journal of Leukocyte Biology provides an overview of tight junctions in asthma, chronic rhinosinusitis, atopic dermatitis, eosinophilic esophagitis, and inflammatory bowel disease (8). While this review doesn’t highlight the role of mast cells, it is interesting to note that research supports mast cell involvement in each of these conditions.

Is your skin leaking?

Diet can help to reduce the severity of your eczema. For a list of foods that can help, download our Shopping List here. It's a good place to start!

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Does this sound like you?

You’re dealing with skin flares, sensitivities, or reactions that don’t fully make sense — and you’re ready for clearer answers.

If histamine, mast cells, or nervous system reactivity might be part of what’s driving your symptoms, we’d love to help you connect the dots.

Our free Master Class, The Histamine Connection, walks you through how histamine and mast cells influence symptoms throughout the body — including the skin — and how to start creating a clearer path forward.

✨ Register for the next live session to join us for the Q&A, or catch the replay if you can’t attend live.