While genetics and the state of the immune system help explain the underlying physiologic cause of psoriasis, there are certain triggers that can tip the scales and precipitate the appearance of red, scaly, itchy patches and plaques on the skin. Smoking, infections, alcohol, certain medications, weather, injuries, and stress can trigger a psoriasis flare.
The body’s response to an internal stress involves multiple systems and pathways. A normal stress response activates the hypothalamus-pituitary-adrenal (HPA) axis and sympathetic adrenomedullary (SAM) axis and results in the elevation of stress hormones like cortisol (Skin Therapy Lett. 2011 May;16(5):1-4). Research has suggested that the stress response in psoriasis patient is altered, which results in lower cortisol levels (Arnetz BB, Fjellner B, Eneroth P, et al. Stress and psoriasis: psychoendocrine and metabolic reactions in psoriatic patients during standardized stressor exposure. Psychosom Med 47(6):528-41.) An altered stress response may cause the accumulation of cells involved in inflammation and stimulate the release of cytokines, which are substances that act as signals between cells.
It is well established that certain cytokines are involved in the pathogenesis of psoriasis. Many of the currently available biologic medications available for psoriasis patients target molecules such as TNF-alpha, IL-17, and IL-23. The increased levels of these cellular signals are directly responsible for the development of the clinical features of psoriasis. For example, the normal process by which skin cells are produced and then shed takes about 4 weeks. In psoriasis, this process only takes a few days, which leads to the accumulation of silver-colored scales on the skin. These cytokines are also responsible for the development of other symptoms of psoriasis, such as red, cracked areas of skin that bleed easily (Bolognia, Dermatology, 4th edition).
The nervous system is also likely involved in psoriasis. Nerves can communicate with skin cells (keratinocytes) to cause them to multiply. Additionally, the interaction of the nervous and immune systems may contribute to itch, which is a common concern among psoriasis patients. (Exp Dermatol. 2020 Jan 18. doi: 10.1111/exd.14071.)
There are lifestyle changes that can help address stress and potentially limit the frequency or severity of psoriasis flares.
Some of these are changes that every person can benefit from, such as exercising, not smoking, avoiding excess alcohol, maintaining a healthy weight, and getting enough sleep. Research suggests that these lifestyle modifications can help the efficacy of psoriasis medications, reduce psoriasis flares, and reduce the risk of developing other diseases that can be associated with psoriasis, such as heart disease, high blood pressure, high cholesterol, and diabetes (https://www.aad.org/public/diseases/psoriasis/insider/diet) (Al-Mutairi N, Manchanda Y. “The effect of weight reduction on treatment outcomes in obese patients of psoriasis on biologic therapy.” J Am Acad Dermatol. 2015;72(5)) (Wu, S, Cho E, et. al. “Alcohol intake and risk of incident psoriatic arthritis in women.” J Rheumatol. 2015;42(5):835-40.)
Psoriasis is a chronic, life-long disease. Patient are encouraged to see a board-certified dermatologist to help them learn more about the disease and how best to manage it.