Stress and the Skin

You have probably noticed how stress can have an impact on some people’s skin. Increasing stress can initiate or worsen skin disorders such as psoriasis and atopic dermatitis. There has also been a lot of discussion about whether stress can also exacerbate acne and cause cold sores to erupt.

A new study published in the December issue of the American Journal of Physiology-Regulatory, Integrative and Comparative Physiology sheds important light on this association.

It is well known that one of the physical effects of stress is to increase levels of a range of steroid hormones called glucocorticoids. The best known glucocorticoid is cortisol or hydrocortisone. So the question was whether the missing link between stress and skin problems might be one or other of the glucocorticoids.

Researchers from the Veterans Affairs Medical Center, San Francisco and the University of California at San Francisco and Yonsei University Wonju College of Medicine, Wonju, Korea decided to study this possible connection.

You may have heard that the skin is the largest organ in the body and provides the critical barrier between the environment and the internal organs. Its most important function is providing a permeability barrier that prevents us from drying out. When we are healthy we are approximately 65-70 percent water. We are able to survive and function in dry environments because the skin forms a permeability barrier that prevents the loss of water.

The physical location of the permeability barrier is in the outermost layer of the epidermis that is known as the stratum corneum. The stratum corneum is composed of dead cells surrounded by lipid membranes. The stratum corneum layer continuously sloughs off, and therefore has to be constantly regenerated. The epidermal cells in the lower epidermis are continuously proliferating to provide new cells, which then differentiate, move toward the surface and ultimately die, to form a new the stratum corneum. This process is going on in your skin right now, though it can be disrupted by damage such as sunburn. If the process becomes overactive, it can lead to the development of thick, hardened skin.

It was already known that psychological stress disturbs this elegantly balanced system by decreasing the proliferation of epidermal cells and inhibiting their differentiation. As a result the function of the permeability barrier is impaired.

To test the hypothesis that glucocorticoids would have adverse effects on skin function, they stressed some hairless mice by putting them in small cages in constant light and forcing them to listen to the radio for 48 hours.

Before being stressed one group of mice was treated with mifepristone, which you may know by its two other names, RU-486, or the “morning after” pill, which blocks the action of glucocorticoids. A second group was given a drug called antalarmin, which blocks glucocorticoid production. A third group was stressed but received neither drug and a fourth group remained unstressed in ordinary cages and without the continuous light and sound to which the other groups were exposed.

The mice that received mifepristone or antalarmin showed significantly better skin function compared to the stressed mice that did not receive either treatment.

The experiment demonstrated the important role that glucocorticoids play in inducing the skin abnormalities brought on by psychological stress. Although we hope that the study will lead to a way to treat people who suffer from these skin conditions, there is still a long way to go. It’s always difficult to extrapolate from mice to people. Second, there may be serious side effects of modulating glucocorticoid activity. Glucocorticoids are essential hormones that play many important roles. Blocking their action could have negative outcomes. This is one of the reasons why we are skeptical about advertisements that claim that some herbal concoction can “cure” cortisol-related obesity. If something could really modify the activity of cortisol or other glucocorticoids in the body, it would likely have many most undesirable effects.

The research team is now looking at the effect of psychological stress on the skin’s production of antimicrobial peptides, which play a role in defense against infection. It has long been thought that psychological stress might also reduce the ability of the skin to protect from infections.

I never like to leave a report involving animal experiments without also saying a heartfelt thank you to the animals that participated in the experiments.

This research is interesting and may have a number of spin offs. But I have another rather obvious question: since we already know that there is a link between stress and some skin problems, why not focus on stress management techniques, rather than trying to find new medicines to help counteract the biochemical effects of stress?