This column is written by medical students and is dedicated to reviewing the science behind obesity and bariatric surgery.
Column Editor: Daniel B. Jones, MD, MS, FACS
Professor of Surgery, Harvard Medical School, Vice Chair, Beth Israel Deaconess Medical Center, Boston, Massachusetts
This month: Impact of Bariatric Surgery on the Severity of Psoriasis
by Gordon Bae
Bariatric Times. 2015;12(2):24–25.
The prevalence of obesity continues to be a staggering figure in the United States. Obesity is defined by a having body mass index (BMI) > 30kg/m2 and currently 34.9 percent of adults, 16.9 percent of youth, and 8.1 percent of infants in the US are obese.[1,2] Obesity is associated with many life-threatening medical co-morbidities such as heart disease and diabetes, costing the US healthcare system an estimated $147 billion dollars in 2008 alone. However, obesity is also associated with numerous severely debilitating but not life threatening conditions.
Psoriasis is a common chronic skin disorder that affects about one percent of the US population and both its prevalence and severity have been associated with obesity.[4–7] Psoriasis is characterized by the presence of well demarcated, erythematous, oval plaques of different shapes and sizes with silvery scales that is most commonly found on the scalp, extensor surfaces, and sacral regions.8 While the exact pathophysiological mechanism is unknown, it is theorized to be caused by interplay of chronic autoimmune effects on the skin and can be broken down into the initiation and maintenance stages.
As described in by Nestle et al in the New England Journal of Medicine, the initiation stage of psoriasis starts with an environmental stressor, such as infection, smoking, or trauma. This causes stressed cells to release factors that ultimately results in the activation of dermal dendritic cells. The dendritic cells migrate into lymph nodes and cause the proliferation of Th1 and Th17 cells. These T cells then circulate around the body and emigrate into the dermis via receptor-ligand interactions in the capillaries of the skin.
The maintenance phase of psoriasis can be seen as a cycle where autoantigens are first presented to the T cells in the skin. This in part activates dermal dendritic cells and causes release of factors, such as tumor necrosis factor alpha (TNF-α), interleukin 23 (IL-23), and nitric oxide. These inflammatory factors, along with many other factors, cause keratinocytes stimulation, proliferation, and production of various antimicrobial peptides. At the same time, activated macrophages cause T cells and dendritic cells to form perivascular bundles and the eventual migration of the T cells from the dermis into the epidermis occurs. These T cells also cause stimulation of keratinocytes and release of antimicrobial peptides. Finally, a feedback loop that comprises activated keratinocytes, fibroblasts, and endothelial cells cause the deposition of excess extracellular matrix into the skin (Figure 1).
Where obesity plays into the pathophysiology of psoriasis is currently unclear; however, there are many inflammatory factors at play in psoriasis and the proinflammatory state caused by obesity may be an associative factor. In fact, adipose tissues produce many inflammatory molecules, such as TNF-α, leptin, WNT5A, and IL-6, which may contribute to psoriasis.[9–11] However, there are some contradictory research which claim that psoriasis may not be caused by but leads to obesity through negative psychosocial impact and change of personal habits.
Studies that have been done on obese psoriatic patients who underwent bariatric surgery help clarify the picture. Several case reports as well as cross sectional and retrospective studies have shown that weight loss caused by bariatric surgery may decrease the severity of psoriasis or eliminate it altogether. In fact, in a review article on bariatric surgery and psoriasis, Sako et al conclude, “Bariatric surgery procedures, in particular the Roux-en-Y gastric bypass (RYGB), may one day be a viable option for obese patients with refractory psoriasis.”
In 2004, a case report by Higa-Sansone et al describes a 55-year-old male patient with severe psoriasis that involved 90 percent of his body surface area (BSA). After undergoing RYGB, he had complete resolution of psoriasis at 12 months postoperatively and no recurrence at 24 months follow up. Similarly, in 2006, de Menezes Ettinger et al published a case report of a man who had been suffering from severe psoriasis for 39 years without remission to any treatment. At four-month follow up after RYGB, he had complete remission of psoriasis without any medications. Then, in 2011, Hossler et al showed that two patients who underwent RYGB had a marked improvement in their psoriasis. One patient’s body surface area (BSA) involvement went from 25 to 9 percent in six months, and the other patient’s BSA involvement went from 75 to <5 percent over the course of six years.
In 2013, Hossler et al followed up the case report with a cross sectional study of 34 adults diagnosed with psoriasis who underwent bariatric surgery between January 2004 to 2009. Sixty-two percent of the patients self-reported improvement in psoriasis. Farias et al improved on this study by quantifying the degree of impact of bariatric surgery on psoriasis. They retrospectively reviewed 10 patients who underwent bariatric surgery between 2008 to 2011 and showed that there was a significant change in the quality of life for these patients using the dermatology life quality index (14.9±6.8 before surgery to 5±6.3 after surgery [p=0.005]). Most recently, Romero-Talamas et al performed a retrospective study of 33 patients diagnosed with morbid obesity and psoriasis undergoing bariatric surgery. They were able to show that 40 percent of patients had an improvement in the severity of psoriasis as shown by downgrade of medications and the percent of BSA involvement after six months of follow up.
Conversely, there also have been reports where psoriasis has worsened after bariatric surgery. In 2008, Pérez-Pérez et al published a case report of a 52-year-old woman with psoriasis whose flares became more frequent and severe after undergoing bariatric surgery. Furthermore, in the studies by Hossler and Farias, 10 and 12 percent of patients developed worsening of their psoriasis.[21,22]
While the exact relationship between obesity and psoriasis is unknown, there seems to be an interplay between the two common debilitating diseases.
As there is conflicting evidence regarding the effect of bariatric surgery on psoriasis, more research is needed. The study done by Farias was small (n=10) and one done by Hossler had a low response rate (33%) and was based on patient recall. Furthermore, the study by Romero-Talamas lacked a quality of life assessment and all the clinical measurements were measured via previous medical records. A larger retrospective or a prospective study quantifying the degree of change in psoriasis severity could help us better understand the complex relationship between bariatric surgery and psoriasis. In the future, further research into the molecular mechanism and immuno-endocrine pathophysiology on these two diseases may offer great insights and treatment options for many patients.
1. Center for Disease Control and Prevention. Adult Obesity Facts. http://www.cdc.gov/obesity/adult/defining.html. Accessed December 30, 2014.
2. Ogden CL, Carroll MD, Kit BK, Flegal KM. Prevalence of childhood and adult obesity in the United States, 2011-2012. JAMA. 2014;311(8):806–814.
3. Finkelstein EA, Trogdon JG, Cohen JW, Dietz W. Annual medical spending attributable to obesity: payer-and service-specific estimates. Health Aff (Millwood). 2009;28(5):w822–831. Epub 2009 Jul 27.
4. Parisi R, Symmons DP, Griffiths CE, Ashcroft DM. Identification and Management of Psoriasis and Associated ComorbidiTy (IMPACT) project team. Global epidemiology of psoriasis: a systematic review of incidence and prevalence. J Invest Dermatol. 2013;133(2):377–385. Epub 2012 Sep 27.
5. Armstrong AW, Harskamp CT, Armstrong EJ. The association between psoriasis and obesity: a systematic review and meta-analysis of observational studies. Nutr Diabetes. 2012;2:e54.
6. Herron MD, Hinckley M, Hoffman MS, et al. Impact of obesity and smoking on psoriasis presentation and management. Arch Dermatol. 2005;141(12):1527.
7. Langan SM, Seminara NM, Shin DB, et al. Prevalence of metabolic syndrome in patients with psoriasis: a population-based study in the United Kingdom. J Invest Dermatol. 2012;132(3 Pt 1):556.
8. Nestle FO, Kaplan DH, Barker J. Psoriasis. N Engl J Med. 2009;361(5):496.
9. Hossler EW, Maroon MS, Mowad CM. Gastric bypass surgery improves psoriasis. J Am Acad Dermatol. 2011;65(1):198–200. Epub 2010 Jul 22.
10. Gerdes S, Rostami-Yazdi M, Mrowietz U. Adipokines and psoriasis. Exp Dermatol. 2011;20(2):81–87.
11. Ståhle M. Psoriasis: In between the skin and the fat. Exp Dermatol. 2014 Dec 2.
12. Herron MD, Hinckley M, Hoffman MS, et al. Impact of obesity and smoking on psoriasis presentation and management. Arch Dermatol. 2005;141(12):1527–1534.
13. Sako EY, Famenini S, Wu JJ. Bariatric surgery and psoriasis. J Am Acad Dermatol. 2014;70:774–779.
14. Higa-Sansone G, Szomstein S, Soto F, Brasecsco O, Cohen C, Rosenthal RJ. Psoriasis remission after laparoscopic Roux-en-Y gastric bypass for morbid obesity. Obes Surg. 2004;14(8):1132–1134.
15. de Menezes Ettinger JE, Azaro E, de Souza CA, dos Santos Filho PV, et al. Remission of psoriasis after open gastric bypass. Obes Surg. 2006;16(1):94–97.
16. Hossler EW, Maroon MS, Mowad CM. Gastric bypass surgery improves psoriasis. J Am Acad Dermatol.2011;65(1):198–200.
17. Hossler EW, Wood GC, Still CD, Mowad CM, Maroon MS. The effect of weight loss surgery on the severity of psoriasis. Br J Dermatol. 2013;168(3):660–661.
18. Farias MM, Achurra P, Boza C, Vega A, de la Cruz C. Psoriasis following bariatric surgery: clinical evolution and impact on quality of life on 10 patients. Obes Surg. 2012;22(6):877–880.
19. Romero-Talamás H, Aminian A, Corcelles R, Fernandez A, Schauer PR, Brethauer S. Psoriasis improvement after bariatric surgery. Surg Obes Relat Dis. 2014;10(6):1155–1159. Epub 2014 Apr 18.
20. Pérez-Pérez L, Allegue F, Caeiro JL, Zulaica JM. Severe psoriasis, morbid obesity and bariatric surgery. Clin Exp Dermatol. 2009;34(7):e421–422.
21. Hossler EW, Wood GC, Still CD, Mowad CM, Maroon MS. The effect of weight loss surgery on the severity of psoriasis. Br J Dermatol. 2013;168(3):660–661.
22. Farias MM, Achurra P, Boza C, Vega A, de la Cruz C. Psoriasis following bariatric surgery: clinical evolution and impact on quality of life on 10 patients. Obes Surg. 2012;22(6):877–880.
FUNDING: No funding was provided.
FINANCIAL DISCLOSURES: The author reports no conflicts of interest relevant to the content of this article.