Inside the Skin Barrier

This website is devoted to the permeability barrier - the most critical, life-enabling function of skin. By preventing loss of water from the skin's surface, the barrier preserves the body's internal milieu against dessication in a dry environment.

Stress Affects The Skin

September 27, 2018 By Peter M. Elias, M.D. 1 Comment

Detail of 10th C sculputre from Lombardy, Italy. Stress has always been with us. We use it here to illustrate how stress affects skin. — 10th Century Scupture from Lombard Region of Italy; now in the Pinocoteca Ambrosiana in Milan. Stress has always been with us. This figure may even be scratching herself, illustrating how stress affects skin. Photo by Mary L. Williams

There seems little doubt that stress affects skin – and not in a good way. As dermatologists, we have often heard from our patients how the stress in their lives is making their skin condition worse. Big pimples erupt just before prom night, or as a wedding approaches. Eczema (or atopic dermatitis) flares during exams or from stress at work. It seems there is widespread belief among patients, if not always their doctors, that stress is bad for health – in general, and across a wide swath of medical conditions. This bad effect of stress on health is most often attributed to weakening (or in some cases perhaps, an over-reacting) of the immune system

But this concept – stress affecting the immune system – seemed too vague. We wondered, “Where’s the beef?” We were indeed convinced from our clinical practice that stress does indeed affect some skin diseases, and especially atopic dermatitis (or eczema). And knowing that the skin barrier is impaired in this condition, we thought that this might be a good place to begin to investigate how stress can affect the skin. [Read more…] about Stress Affects The Skin

2018 IID Meeting Update: Even Fat Is Linked To The Skin Barrier

July 12, 2018 By Peter M. Elias, M.D. Leave a Comment

Fat is healthy for elephant seals. Could it also be good for the skin barrier as dome fat is for humans? — Resting elephant seals on San Simeon State Beach.

Fat Cells And The Skin Barrier?

What do fat cells have to do with the function of the epidermal permeability barrier? Before the recent International Investigative Dermatology Meeting in Orlando, we – although generally obsessed with all things related to the skin’s permeability barrier – would reluctantly have had to admit, “Alas, nothing.”

Therefore, we were most intrigued to learn of the discovery by Dr. S. Hong, of Dankook University in Cheonan, Korea, and his colleagues that some of our fat cells are at work, fine-tuning the permeability barrier. [Read more…] about 2018 IID Meeting Update: Even Fat Is Linked To The Skin Barrier

How The Skin Barrier Works

May 25, 2018 By Peter M. Elias, M.D. Leave a Comment

The skin barrier is like a brick wall. The cells or "bricks" are surrounded by fat (lipids) or "mortar" — The outermost layers of skin, the stratum corneum, is like a brick wall. The cells, or ‘corneocytes,’ which no longer contain nuclei and are considered dead, are the ‘bricks.’ They are surrounded by membrane sheets composed of lipids (fats). The fibrous protein-filled cells impart mechanical strength, while the lipids prevent water movement across the stratum corneum.

To understand how the skin barrier works, we need to return to our ‘bricks and mortar’ model of the outermost layers of the epidermis, the ‘stratum corneum.’ In this layer, the cells (called ‘corneocytes’) no longer possess a nucleus – they are essentially dead. But they are filled with tough, fibrous proteins, called ‘keratins,’ and many small molecules derived from the breakdown of proteins and other components of these once-living cells.

Simply stated, the bricks (or corneocytes) provide a durable defense against the ordinary frictional wear and tear of life.

As long, protein polymers, it is the keratins that give the skin much of its remarkable mechanical strength. Another contributor to its strength is another protein structure, the so-called ‘cornified envelope.’ This polymer is made up of several different protein precursors. It surrounds the corneocyte, rather like a hedgerow of rose bushes, and replaces the cell membrane of the former, living cell. [Read more…] about How The Skin Barrier Works

Dermatologists, Sun Bathing and Eczema

February 5, 2016 By Peter M. Elias, M.D. & Mary L. Williams, M.D. Leave a Comment

Dermatologists can be accused of having contradictory attitudes towards sun exposure. On the one hand, to prevent skin cancer we routinely advise against sun bathing, but on the other, we often treat common skin disorders like eczema (“atopic dermatitis“) or psoriasis with ultraviolet (UV) light. Now there is even reason to think that too little exposure to sunlight may be why allergic diseases, like atopic dermatitis, have become so much more common in recent years. What is going on with sunlight and the skin?

Unquestionably, sunburns damage the skin and promote the development of skin cancer. There is no known “safe” amount of sun exposure that does not produce the biochemical changes in skin which are linked to cancer. For this reason, dermatologists do not consider suntans to be healthy for the skin, either. Suntans, like freckles, are properly considered an injury response of the skin to excessive sun exposures. Hence, our general recommendation is to: cover up, use sunscreens on sun exposed areas and get your necessary vitamin D through diet and dietary supplements.

Yet, ultraviolet light therapy is a time honored and effective treatment for inflammatory skin conditions, like atopic dermatitis and psoriasis. Typically these treatments which use the sunburning, UV-B, portion of the sun spectrum are given in the physician’s office, to prevent over-dosage. The desired exposures are ‘sub-erythemogenic’, meaning they are below those that will produce skin redness or sunburn. [Read more…] about Dermatologists, Sun Bathing and Eczema

Black Skin Is Better

August 6, 2015 By Peter M. Elias, M.D. Leave a Comment

This proposition – that black skin is better skin – is not a political statement. Rather, it is based upon scientific observations. Darkly pigmented skin is functionally superior to lighter colored skin in several ways. Our purpose here is give our readers a scientific perspective to a socially fraught question. And to acquaint our readers with some of the most important functions of skin that are influenced by skin color.

tulips2 504 — Image by Mary L. Williams, M.D.

Some of the benefits of skin color are obvious and widely recognized. Darkly pigmented skin is less susceptible to skin cancer. And dark skin is less prone to develop wrinkles over time.

Poetically speaking, age has a lighter stroke on the canvas of black skin.

But there are other, less well-known, but very important ways in which darkly pigmented skin functions better than pale skin. We are not talking about “racial” differences, because race is not a valid scientific construct. The differences we speak of are attributable to skin pigmentation per se in whomever and wherever it is found. Whether in an African-American, Filipino, or Sri Lankan, it is dark pigmentation itself that confers multiple advantages to the part of the skin called ‘epidermis’, which comprises the outermost and protective layers of the skin. [Read more…] about Black Skin Is Better