Psoriatic Arthritis: A Skin Condition Gone Wrong

Itchy, red, scaly skin is a hallmark sign of psoriasis. Up to 30% of people who get psoriasis also develop a joint condition called psoriatic arthritis.¹Takeshita J, Grewal S, Langan SM, et al. Psoriasis and comorbid diseases: Epidemiology. J Am Acad Dermatol. 2017;76(3):377–390. doi:10.1016/j.jaad.2016.07.064. As cited in Ford AR, Siegel M, Bagel J, et al. Dietary Recommendations for Adults With Psoriasis or Psoriatic Arthritis From the Medical Board of the National Psoriasis Foundation: A Systematic Review. JAMA Dermatol. 2018;154(8):934–950. doi:10.1001/jamadermatol.2018.1412.

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What separates the people who have psoriasis from the people who develop full-blown psoriatic arthritis? Doctors aren’t completely sure. Evidence suggests many factors are at play, including genetics and lifestyle.

How do genes influence psoriatic arthritis?

Several genes may contribute to psoriasis and psoriatic arthritis. Researchers know a gene called HLA-C06 increases the risk of developing psoriasis but not psoriatic arthritis. Other genes, such as HLA-B08, HLA-B27, HLA-B38 and HLA-B39, are linked to psoriatic arthritis.²Christopher T. Ritchlin, M.D., M.P.H., Robert A. Colbert, M.D., Ph.D., and Dafna D. Gladman, M.D. "Psoriatic arthritis." New England Journal of Medicine. March 9, 2017. DOI: 10.1056/NEJMra1505557.

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Genes can increase risk, but are not a guarantee
Does having one of the HLA-B genes mean you’ll definitely get psoriatic arthritis? No. Many people have these genes and never develop psoriasis or psoriatic arthritis. Likewise, a person who has none of the genes mentioned above, or has just the HLA-C06 gene, can still develop psoriatic arthritis.

Can people prevent psoriatic arthritis?

No one knows how to prevent psoriatic arthritis, and there are no agreed-upon guidelines for reducing the risk of developing it. A few lifestyle changes may hold promise.

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Lose weight. While doctors can’t say whether maintaining a healthy weight decreases the risk of developing psoriatic arthritis, losing excess weight can decrease inflammation in the body (psoriatic arthritis is an inflammatory disease). In addition, research suggests that eating fewer calories to lose excess weight helps reduce psoriasis outbreaks.³Alotaibi HA. Effects of Weight Loss on Psoriasis: A Review of Clinical Trials. Cureus. 2018;10(10):e3491. Published 2018 Oct 24. doi:10.7759/cureus.3491. Losing weight also seems to decrease symptoms of psoriatic arthritis in people who already have it.⁴Ford AR, Siegel M, Bagel J, et al. Dietary Recommendations for Adults With Psoriasis or Psoriatic Arthritis From the Medical Board of the National Psoriasis Foundation: A Systematic Review. JAMA Dermatol. 2018;154(8):934–950. doi:10.1001/jamadermatol.2018.1412.

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Foster a healthy gut microbiome. People who have an imbalance of microbes in their intestinal tracts—a condition called gut dysbiosis—are more likely to develop psoriatic arthritis than people with normal gut microbiomes. Avoiding unnecessary antibiotic treatment; eating a plant-based diet that emphasizes leafy greens; and sticking to an exercise routine may all have positive effects on the gut microbiome.

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Eat more omega-3 fatty acids. There is limited evidence that omega 3 fatty acids from fish oils may reduce symptoms of psoriasis.⁴Ford AR, Siegel M, Bagel J, et al. Dietary Recommendations for Adults With Psoriasis or Psoriatic Arthritis From the Medical Board of the National Psoriasis Foundation: A Systematic Review. JAMA Dermatol. 2018;154(8):934–950. doi:10.1001/jamadermatol.2018.1412. Salmon, mackerel, sardines and other fatty fish are particularly rich sources of omega-3s.

See 9 Foods That Are Rich in Powerhouse Omega-3s

While there is not evidence that eating fish or taking an omega-3 fish oil supplement will reduce the risk of developing psoriatic arthritis, some doctors may recommend it because of the potential benefits and the relatively low risk of side effects. (All medications and supplements carry some risk.)

Take a vitamin D supplement. About 40% of people with psoriatic arthritis have low levels of vitamin D, compared with about 25% of people who don't have a psoriatic disease.⁵Urruticoechea-Arana A, Martín-Martínez MA, Castañeda S, et al. Vitamin D deficiency in chronic inflammatory rheumatic diseases: results of the cardiovascular in rheumatology [CARMA] study. Arthritis Res Ther. 2015;17(1):211. Published 2015 Aug 14. doi:10.1186/s13075-015-0704-4. While taking vitamin D has not been shown to prevent or cure psoriatic arthritis, evidence suggests it may reduce symptoms of both psoriatic arthritis and psoriasis.

People are advised to consult with their primary care provider before taking any supplements.

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Prevention recommendations may become available as we learn more about how psoriasis and psoriatic arthritis develop.

Learn more:

Psoriatic Arthritis Diagnosis

Types of Arthritis