It is widely held that the stress of our modern lives is bad for our health. And it is certainly true that stress (or, more precisely, ‘psychological stress’) can be harmful to the function of our skin. It delays wound healing. It can reduce our immune defenses against infection. And, as we demonstrated several years ago, it can compromise the skin’s permeability barrier. It is also accepted by many that stress exacerbates chronic inflammatory diseases, like rheumatic disorders and inflammatory bowel diseases, such as ulcerative colitis and Crohn’s disease, as well as skin conditions, like psoriasis and eczema (atopic dermatitis).
It makes sense, of course, that the stress response to acute threats – like a tiger attack – was beneficial to early man. This is the famous “Fight or Flight” response system. But why has the stress response to chronic challenges, like illness, persisted? If the effects of psychological stress during illness are all bad – then would not mutations that weakened this deleterious stress response have been favored by natural selection long ago? The answer, as we reported here, may be that the stress response to illness is, in fact, not always harmful.
In these studies, we used several mouse models of inflammatory skin disorders, including atopic dermatitis, allergic contact dermatitis, and irritant contact dermatitis, and evaluated the response to psychological stress (for our mice, the stress was ‘frustration’, when we restricted their ability to move about). To our surprise, their dermatitis did not worsen with the addition of stress, as we had hypothesized, but, instead their rashes even improved!
Stress is well known to stimulate an increase in the circulation of corticosteroid hormones (‘cortisone’), which are potent anti-inflammatory molecules. Therefore, we considered the possibility that the improvement in their rashes could be due to a stress-induced increase in these hormones, which are commonly employed to treat inflammatory conditions. Indeed, stress increased the blood levels of circulating corticosteroids and improved inflammation in all of these models. Conversely, pharmacological blockade either of the increase in steroids or their action worsened the disease in all. Even in the absence of stress, blockade of steroid action in atopic dermatitis worsened the condition.
Bottom Line: These findings suggest that stress, with its increased production of cortisone, can be beneficial during inflammatory illnesses. This may be why the response to chronic psychological stress has been conserved during evolution.
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