Psoriatic Arthritis: What You Need to Know
Psoriatic arthritis is a chronic type of joint inflammation in psoriasis that may develop in 4 to 30% of people who have psoriasis.[1,2] Psoriatic arthritis tends to develop about ten years after the person gets psoriasis. Adults between the ages 30-55 are more commonly affected, but children can also get psoriatic arthritis. Women and men are equally affected. Though any joints in the body may be affected, the most commonly affected joints are the fingers and wrists. A single joint or several joints may be affected at one time. The inflamed joints may become painful, swollen, and feel hot and stiff. Psoriatic arthritis can affect the lower spine and cause chronic low back pain in 40% of people who have psoriatic arthritis. Men are more likely to have spinal involvement than women. Additionally, the tendons around the ankles and feet may be inflamed and cause ankle and feet swelling. With time, chronic inflammation can permanently destroy the joints and cause significant disability. Therefore, early diagnosis and treatment by a health professional is important in limiting damage to the joints.
What Causes Psoriatic Arthritis?
The exact cause of psoriatic arthritis is unknown, but several factors have been linked to its development.
Overall, research shows that the genetic makeup of a person may increase the chances of developing psoriatic arthritis. For example, people with a specific sequence in their DNA, called HLA-B27, are more likely to get certain auto-inflammatory conditions, including psoriatic arthritis. About 40% of those who have psoriasis or psoriatic arthritis have a first-degree relative with psoriasis. People who have a first degree relative with psoriatic arthritis can be 55 times more likely to get psoriatic arthritis than the general population.
Overly active immune system
An overly active immune function causes the release of molecules that cause inflammation in the skin, nails, and joints in people with psoriasis.
The timing of viral and bacterial infections has been associated with the development or worsening of psoriatic arthritis.[8,9]
A few studies have suggested that physical trauma and injuries may induce psoriatic arthritis in people who also have psoriasis.[10,11]
Can I Get Psoriatic Arthritis Without Skin Psoriasis?
Yes. In fact, up to 15 % of people can get joint inflammation in psoriasis before the skin is affected. People who have psoriatic nail changes such as pitting, ridging, cracking, and pigment changes are more likely to get psoriatic arthritis.
How Is Psoriatic Arthritis Diagnosed?
When psoriatic arthritis is suspected, a health professional may ask about health history and perform a physical examination, blood tests, and X-rays or other imaging tests to more accurately diagnose psoriatic arthritis and monitor disease progression.
How Is Psoriatic Arthritis Treated?
Just like psoriasis, there is no cure for psoriatic arthritis. The main goal for treatment is to decrease the inflammation in the joints in order to decrease the discomfort and prevent further joint damage. Unlike skin psoriasis, psoriatic arthritis cannot be treated with topical anti-inflammatory medications or phototherapy. Oral or injectable anti-inflammatory medications are needed to control the joint inflammation in psoriasis to prevent joint destruction. The most common types of medication used to treat psoriatic arthritis are:
- Nonsteroidal anti-inflammatory drugs (NSAIDS): NSAIDs such as ibuprofen, naproxen, diclofenac, indomethacin, and celecoxib may help temporarily decrease joint pain and swelling. NSAIDS are mainly used to control symptoms.
- Disease-modifying anti-rheumatic drugs (DMARD): DMARDs can help limit the amount of joint damage caused by inflammation. These medications may need to be taken for months and years. Methotrexate and leflunomide are commonly prescribed DMARDs for psoriatic arthritis.
- Biologics: Biologics are a group of medications made from living cells cultured in the laboratory. This group of medications directly target a specific part of the immune system that causes psoriasis. Some examples of biologics used to treat psoriatic arthritis are TNF inhibitors (etanercept, infliximab, adalimumab), interleukin IL-12/IL23 inhibitors (ustekinumab), and IL-17 pathway inhibitors (secukinumab, ixekizumab, and brodalumab).[14-16]
- Steroid Injections: Health professionals may inject corticosteroids directly into the affected joint space to treat joint inflammation.
- Joint surgery: People with severely damaged joints may be candidates for orthopedic surgery to correct or replace the affected joints. However, if the psoriatic arthritis is still ongoing, a health provider may elect to control the ongoing inflammation before surgery.
- Zachariae H. Prevalence of joint disease in patients with psoriasis: implications for therapy. Am J Clin Dermatol.2003;4(7):441-447; PMID: 12814334 Link to research.
- Shbeeb M, Uramoto KM, Gibson LE, et al. The epidemiology of psoriatic arthritis in Olmsted County, Minnesota, USA, 1982-1991. J Rheumatol.2000;27(5):1247-1250; PMID: 10813295 Link to research.
- Wilson FC, Icen M, Crowson CS, et al. Time trends in epidemiology and characteristics of psoriatic arthritis over 3 decades: a population-based study. J Rheumatol.2009;36(2):361-367; PMID: 19208565 Link to research.
- Eder L, Thavaneswaran A, Chandran V, et al. Gender difference in disease expression, radiographic damage and disability among patients with psoriatic arthritis. Ann Rheum Dis.2013;72(4):578-582; PMID: 22589379 Link to research.
- Amherd-Hoekstra A, Naher H, Lorenz HM, et al. Psoriatic arthritis: a review. J Dtsch Dermatol Ges.2010;8(5):332-339; PMID: 20015187 Link to research.
- Liu Y, Helms C, Liao W, et al. A genome-wide association study of psoriasis and psoriatic arthritis identifies new disease loci. PLoS Genet.2008;4(3):e1000041; PMID: 18369459 Link to research.
- Gladman DD. Toward unraveling the mystery of psoriatic arthritis. Arthritis Rheum.1993;36(7):881-884; PMID: 8318035 Link to research.
- Ritchlin C, Haas-Smith SA, Hicks D, et al. Patterns of cytokine production in psoriatic synovium. J Rheumatol.1998;25(8):1544-1552; PMID: 9712099 Link to research.
- Prinz JC. Psoriasis vulgaris--a sterile antibacterial skin reaction mediated by cross-reactive T cells? An immunological view of the pathophysiology of psoriasis. Clin Exp Dermatol.2001;26(4):326-332; PMID: 11422184 Link to research.
- Pattison E, Harrison BJ, Griffiths CE, et al. Environmental risk factors for the development of psoriatic arthritis: results from a case-control study. Ann Rheum Dis.2008;67(5):672-676; PMID: 17823200 Link to research.
- Scarpa R, Del Puente A, di Girolamo C, et al. Interplay between environmental factors, articular involvement, and HLA-B27 in patients with psoriatic arthritis. Ann Rheum Dis.1992;51(1):78-79; PMID: 1540042 Link to research.
- Jean Bolognia JJ, Julie Schaffer. Third Edition, Volume 2. Elsevier Publishing. Dermatology.
- Nash P, Clegg DO. Psoriatic arthritis therapy: NSAIDs and traditional DMARDs. Ann Rheum Dis.2005;64 Suppl 2:ii74-77; PMID: 15708943 Link to research.
- Gottlieb AB, Greb JE, Goldminz AM. Psoriasis Trends and Practice Gaps. Dermatol Clin.2016;34(3):235-242; PMID: 27363878 Link to research.
- Nash P, Kirkham B, Okada M, et al. Ixekizumab for the treatment of patients with active psoriatic arthritis and an inadequate response to tumour necrosis factor inhibitors: results from the 24-week randomised, double-blind, placebo-controlled period of the SPIRIT-P2 phase 3 trial. Lancet.2017;389(10086):2317-2327; PMID: 28551073 Link to research.
- Mease PJ, Genovese MC, Greenwald MW, et al. Brodalumab, an anti-IL17RA monoclonal antibody, in psoriatic arthritis. N Engl J Med.2014;370(24):2295-2306; PMID: 24918373 Link to research.