How stress affects the skin

Stress can have a diverse array of effects on the skin. The skin even has a stress system built in, complete with stress hormones. Let’s find out how stress affects the skin and how to avoid skin damage.

Stress can have many negative effects on the body. One of the organs that can be affected is the skin. The skin can receive stress directly from the outside world, and is at the same time a target of the biological stress responses from within the body. As the largest organ of the body, the skin provides a barrier between the interior of the body and the external world, and plays a role in the defense against invading microorganisms.

The skin is composed of two major layers: epidermis and dermis. The epidermis is a continuously renewing layer. The outermost layer of the skin is the epidermis, with the stratum corneum (SC) on top. The stratum corneum is composed of dead and flattened cells, called corneocytes, that are embedded in a matrix of lipids. This is the layer of the skin that we can see from the outside. The dermis is the middle layer composed of other cells, called fibroblasts, and an extracellular matrix which makes the skin elastic and strong.

Skin as a sensory organ

Skin is the primary sensory organ for external stressors, the things that cause stress. These stressors include temperature (heat and cold), pain and pressure. These are sensed by specialized receptors located in the skin. The receptors send the information about temperature, pain and pressure to the spinal cord and from there to the brain. Stress reactions will be triggered there if the incoming information is stressful.

The skin also harbors sensory fibers coming down from the brain, which sense changes in temperature, acidity (pH) and inflammatory changes provoked by infections. The brain responds to these signals, which causes stress responses in the skin.

The skin is not only a target of the stress reactions elicited by the brain, but can also elicit stress responses by itself. These are important for inflammation and the defense against bacteria and viruses that try to invade the body.

Stress reactions in the brain and skin

The stress reactions that are elicited by the brain commence in the hypothalamus, at the base of the brain. In the hypothalamus, a substance called “corticotropin-releasing factor”, or CRF for short, is produced during stress. CRF is transported to the pituitary gland (also known as hypophysis), and stimulates the release of another stress hormone, ACTH. ACTH stimulates the synthesis of the stress hormone cortisol in the adrenal gland. Cortisol travels throughout the body and regulates a wide spectrum of stress responses. This hormonal cascade from the hypothalamus via the pituitary gland to the adrenals is known as the hypothalamus-pituitary-adrenal axis, or HPA axis for short. The HPA axis is one of the two most important systems in our body that elicit stress reactions.

The skin has developed an essentially identical system, with local production of the stress hormones CRF and ACTH. CRF and ACTH have many functions in the skin, which are in essence geared to promote inflammation and blood flow.

Another stress hormone that is released under the influence of the brain is adrenaline, also known as epinephrine. This stress hormone accelerates heart rate and respiration, and widens the blood vessels in the muscles. This makes a “fight-or-flight” reaction possible, which stimulates active coping with a stressor.

Epinephrine is also produced locally in the skin. Here, it acts, among others, on fibroblasts in the dermins. Epinephrine promotes their migration and collagen production. Both of these are important steps in wound healing.

The stress hormones in the skin do not work alone. There are many other factors with which they act together. Many of those are released by nerve endings from the peripheral nervous system. These factors are, like the typical stress hormones, involved in inflammation. Also, the skin contains many more cell types than those we have mentioned here. These cells can secrete stress hormones, or factors that promote inflammation, cell division or cell differentiation (so that they become a specific type of cell). Finally, many cells of the defense system (also known as the immune system) can be found in the skin, as a first line of defense against invaders.

Skin inflammation during stress responses

Stress can affect various diseases and conditions, such as asthma, arthritis, migraines and multiple sclerosis. Typical conditions in the skin are related to inflammation, for example psoriasis, atopic dermatitis, acne, contact dermatitis, alopecia areata, itch or pruritus, and erythema. We will focus only on three of them: psoriasis, acne, and atopic dermatitis.

Psoriasis

Psoriasis is a chronic skin inflammatory disease, affecting about 2% of populations worldwide. It is characterized by cell division of a particular cell type, the keratinocytes, and inflammation. These two conditions lead to the formation of plaques (epidermal hyperplasia), which occur mostly over the elbows, knees and scalp. Other symptoms include dysregulated blood vessel formation and several problems with the immune system. There is currently no cure for psoriasis, although a new treatment to reduce inflammation seems promising.

Stress is like a double edged sword for psoriasis. On the one hand, stress can be the consequence of having to live with psoriasis. On the other hand, stress worsens psoriasis. The factors that promote inflammation, which are present in large quantities in psoriasis, activate the stress reactions in the brain. This might lead to a vicious cycle that maintains and worsens psoriasis. It is thought that psoriasis stress also has an impact on the stress hormones in the skin itself, but it is not precisely known what the role of these stress hormones is in psoriasis.

Stress that is unrelated to psoriasis will also worsen the condition. It is thus important to reduce or avoid stress as much as possible to keep psoriasis under control. For clarity: stress has not been described as a cause of psoriasis, but stress does exacerbate it.

Acne

Acne vulgaris (or acne for short) is a very common skin disease. It affects a majority of people at some point in their life. Acne occurs on the skin regions with the densest occurrence of sebaceous glands in the hypodermis, the most inner layer of the skin, right below the dermis. Sebaceous glands are very small glands that open into a hair follicle, where they secrete an oily or fatty substance, called sebum. Sebum lubricates the hair and skin of mammals. The highest concentrations of sebaceous glands are found on the face, the upper part of the chest, and the back. Acne is characterized by increased colonization of the skin by P. acne bacteria (hence the name), and further by increased sebum production, and inflammation.

Although stress had been suspected to induce acne, it was not until the early 2000s that this was formally established. This was done in a student examination stress study, and it was shown that acne severity was associated with stress levels.

Acne is directly related to the stress hormones in the skin. Both CRF and ACTH stimulate the production of sebum and proinflammatory factors. Facial skin of acne patients have furthermore a lot of another factor, called substance P (SP). SP helps to produce the fatty or oily substance of sebum, and stimulates inflammation.

Atopic Dermatitis

Atopic dermatitis (AD for short) is a chronic and relapsing inflammatory skin disease. It is often associated with eczema and itch. In AD, the barrier function of the skin seems to be defective. Environmental factors such as microorganisms or allergens (substances that can induce allergies) can trigger or complicate the disease.

As we have seen for psoriasis, AD symptoms and stress seem to form a vicious cycle. Psychological stress can exacerbate the pathology, and this can in turn activate the stress reactions in the brain. On top of that, on average more AD patients have been reported to suffer from anxiety and depression than people without AD.

Stress can worsen skin inflammation in AD patients considerably, and inflammation influences stress reactions leading to cortisol and epinephrine production. In the skin, factors released by peripheral nerve endings increase inflammation further. Scientists are currently investigating how these factors augment inflammation and affect the immune system.

Effects of stress on skin barrier function and wound repair

We have discussed above the role of stress in worsening skin diseases. But does stress also have negative effects on healthy skin?

To answer this, we have to look at two of the functions of the skin in more detail. These are the barrier function and wound repair.

Skin barrier function

The skin protects the body from invading microorganisms and dehydration. It acts as a physical barrier, which is composed of a special mixture of skin proteins and lipids. Disruption of this barrier function can lead to flaky or dry skin.

Studies with laboratory animals have shown that stress can cause water loss through the skin. This is a clear sign that the barrier function of the skin is compromised. This is caused by the stress hormones CRF and cortisol, which reduce the production of the lipids (or fatty molecules) that make up the skin barrier. In humans, similar effects have been found. For example, exam stress, interview stress and stress due to marital disruption all affect the skin barrier function and activate the part of the immune system that induces inflammation.

Wound repair

One of the skin’s major functions is wound repair following injury. Wound repair starts with the inflammation phase. In this phase, inflammatory molecules produced by the immune system protect the body against infections, and attract several cell types to the site of injury that are important to close the wound. The cells are important for the second phase of wound repair, the proliferation phase, when new cells, blood vessels and collagen are built. Finally, in the remodelling phase, the collagen is properly put in place and unnecessary cells are being removed. This phase may take weeks or months.

Stress has been shown to slow down wound repair. This was first clinically demonstrated in humans, when caregivers of demented relatives need 20% more time for complete wound healing. The stress hormone cortisol is the major culprit. Cortisol lowers the amount of inflammatory molecules that are necessary in the first phase of wound repair, the inflammation phase. Epinephrine, another major stress hormone, also has a negative influence on wound repair. It slows down the production of new cells and collagen, and can even reduce blood flow to the site of injury so that oxygen supply is reduced. This slows down the activity of the cells that are responsible for closure of the wound.

Thus, stress can influence skin barrier function and wound repair, but these functions recover once the stress is over. But would skin damage be permanent when the stress becomes chronic?

Long term skin damage by chronic stress

In contrast to acute stress (sudden stress of short duration), chronic stress usually reduces the activity of the immune system, so that the body is less protected against microorganisms. Therefore, chronic stress enhances susceptibility to infections. Chronic stress also worsens some allergic and inflammatory diseases. The effects of chronic stress on the skin are best seen in the altered presence of molecules produced by the immune system.

One of the effects of chronic stress is “skin aging”. Skin aging is characterized by the formation of lines and wrinkles, increased pigmentation, loss of elasticity and firmness, and dull skin. UV irradiation can cause skin aging, and stimulates the production of stress hormones locally in the skin. The skin is under daily UV stress, so that the repeated production of stress hormones can have detrimental effects on the skin. Think of that when you go sunbathing at the beach!

Other confirmed chronic stressors that accelerate skin aging importantly are smoking and air pollution. Also stress caused by lack of sleep can cause skin aging and slower recovery of disrupted skin barrier function.

Long term glucocorticoids (cortisol and similar molecules) therapy for treating skin inflammatory disease has severe side effects, such as reduced thickness of the skin, reduction of number of cells that produce collagen, and a reduction of the number of fibers in the skin. These effects are also found in skin aging, again demonstrating that stress hormones, especially cortisol, is an important factor for the development of skin aging. On top of that, cortisol (and epinephrine) can damage the DNA in the skin, which is a risk factor of cancer.

DNA damage can also lead to the shortening of telomeres. Telomeres are the ends of chromosomes, and shorten with each cell division. This shortening leads eventually to the cessation of cell division, so that no new cells will be formed. Stress can accelerate telomere shortening and premature skin aging.

In conclusion, chronic stress can damage the skin permanently. This has been shown for a variety of stressors, including psychosocial stress (for example stress at work).

8 ways to reduce or prevent the effects of stress on your skin

There is a huge industry promoting creams and treatments to prevent or reduce the effects of stress on your skin. Creams may contain ceramides, hydrating hyaluronic acid, anti-inflammatory honey, antioxidants and other exotic products that are claimed to feed the skin, calm it down, and improve the skin's barrier function. These so-called cosmeceuticals are being promoted as having therapeutic benefits to the skin. This would imply that cosmeceuticals could replace prescribed medical drugs to improve skin function. However, and in contrast to popular belief, this is rather a marketing ploy to make clients feel good about the product they buy - for a premium price. While it may be true that creams and moisturizers may change the appearance of the skin (lighter, less wrinkles, smoother, etc.), making it look healthier (shiny for example) they cannot substitute for medical treatment of skin problems.

Thus, what should you do? The answer is of course: avoid stress! Or, when this is not possible, manage stressful events better! Doing this successfully will do your skin more good than applying creams and moisturizers. And it is better for your health in general too.

Avoiding stress:

1. Quit smoking. This may be difficult to do for some, but the effort is more than worth it. Not only will your skin thank you for quitting, but also your lungs.

2. Avoid sunbathing, and if you do, apply sunscreen. Agreed, sunlight is important for health, as it stimulates the production of vitamin D. However, excessive sunbathing at the beach exposes the skin to too much UV irradiation. Just being in the sun for 20 minutes per day during summer is sufficient.

3. Get enough sleep. Eight hours per night seems to be optimal for most people.

Managing stress:

1. Read all the information about stress on stressinsight.com. This will give you an excellent basal understanding of what stress is, and what you can do to handle stress better.

2. Take control over your daily activities, be it at work or your private life.

3. Take the time to do things you enjoy.

4. Exercise regularly. Exercise helps to reduce stress, and is therefore good for your skin. Also, it has positive effects on the brain and the rest of the body.

5. Try to find out what causes stress. You can do this by yourself, or by talking to somebody, be it a friend, a psychologist or psychiatrist. Here at stressinsight.com we can also help you with this. Check out our course "Surmounting Stress"!