The complex relationship between stress and the skin can likely be influenced by the placebo effect resulting from many psychological interventions, an expert says.
Buenos Aires, Argentina - The impact of stress reduction techniques on dermatologic problems can be explained, largely, by the placebo effect, an expert says.
"It's clear that disfiguring diseases such as acne, psoriasis and eczema are associated with an increased stress level in the patient, deriving from these diseases,"says Francisco Tausk, M.D., professor of dermatology and psychiatry, University of Rochester, New York.
It's also clear that stress worsens skin disease, resulting in a vicious circle, he says.
"But in the past few years," he says, "it's become obvious that there's a close connection between these three systems and the skin."
The central nervous system and skin not only come from the same embryological origin, but the skin also has the potential to produce most of the molecules that act in the hypothalamus-pituitary-adrenal (HPA) axis.
Further, Dr. Tausk says, "The skin can produce corticotrophin releasing hormone and POMC. It also has the capability of cleaving proopiomelanocortin (POMC) and generating molecules like alpha melanocyte stimulating hormone (alpha-MSH), adrenocorticotropic hormone (ACTH) and even cortisol."
In recent years, the concept of allostatic load has replaced the traditional notion of stress (McEwen BS. N Engl J. Med. 1998(338):171-179), he says.
In short, allostasis represents a balanced state that's interrupted by stressors, which trigger a number of physiologic responses, including cortisol secretion, to which the organism must adapt, Dr. Tausk says.
However, he says, "Some individuals are unable to respond appropriately."
For example, repeated stressors of different types - such as a car wreck and an unrelated death in the family - could overload certain patients, creating what's called an allostatic load.
Other individuals fail to adapt to common stressors over time, to the point that an activity like public speaking produces the same level of anxiety each time.
Still other individuals respond properly but don't recover - their cortisol remains elevated after the stress has abated.
The group of patients perhaps most relevant to dermatologists includes those who can't mount adequate responses to stressors due to very low levels of cortisol response.
"Patients that have diseases such as atopic eczema or psoriasis respond in this manner. When they get stressed, they don't produce a normal level of cortisol," though it's more persistent than normal, Dr. Tausk says.
This suggests that these patients can't produce enough cortisol to address the stressors and combat their disease, which explains why exposure to stress tends to worsen their disease, he says.
Alterations to the hypothalamus that are responsible for inadequate cortisol secretion can be either inherited or acquired, Dr. Tausk says.
Stress and infectious disease
Stress, furthermore, favors infectious diseases. For instance, one 500-subject experimental study showed a strong correlation between chronic stress and the development of colds (Cohen S, Tyrrell DA, Smith AP. N Engl J Med. 1991 Aug 29;325(9):606-12).
Several animal studies have shown similar relationships. More specifically, research shows mice housed alone heal more slowly from wounds, Dr. Tausk says.
In another study, mice exposed to stress developed UV-induced tumors much more quickly than their counterparts (Parker J, Klein SL, McClintock MK, Morison WL, Ye X, Conti CJ, Peterson N, Nousari CH, Tausk FA. J Am Acad Dermatol. 2004 Dec;51(6):919-22).
"Stress also affects the skin barrier function," Dr. Tausk says.