1. Health
Send to a Friend via Email

Psoriatic Arthritis and Bone-Joint Damage

By Rosalyn Carson-DeWitt

Updated June 14, 2008

(LifeWire) - You may be familiar with the skin disease psoriasis, but you may not realize that about 5% of individuals with psoriasis develop a related form of arthritis: psoriatic arthritis tenderness, pain, or stiffness and swelling of the joints.

There are different types of psoriatic arthritis:

  1. Symmetric arthritis -- Strikes joint pairs (for example, both knees or both wrists), can cause disability, and affects about 15% of people with psoriatic arthritis.
  2. Asymmetric arthritis -- Affects only one joint of a pair (for example, only one knee would be involved),  affects fingers or toes by often swelling and resembling sausages, and accounts for about 70% of all cases of psoriatic arthritis, which tends to be milder than other forms.
  3. Distal interphalangeal predominant (DIP) -- Involves fingernails, toenails or both, as well as the last joint on the fingers or toes, and accounts for about 5% of cases.
  4. Spondylitis -- Involves the spinal column with swelling and stiffness anywhere from the neck to the base of the spine, making movement difficult and painful, and may involve joints in the arms, hands, legs and feet. Spondylitis generally appears later in the course of psoriatic arthritis and in older patients, is usually more severe in men than in women, and accounts for about 5% of cases.
  5. Arthritis mutilans -- Extremely severe form of the disease that involves the small joints in the hands and feet, as well as the neck and lower back. This can cause joint destruction, deformity and serious disability, and affects fewer than 5% of people with psoriatic arthritis.

Your first bout of psoriatic arthritis may be one type, but subsequent episodes could involve other types. The severity of your skin disease doesn't directly correspond to your risk for psoriatic arthritis, nor how severe your joint disease will be.

Who Gets Psoriatic Arthritis?

About as many men as women develop psoriatic arthritis -- most are between 30 and 50 years old. You're much more likely to develop this condition if you or a member of your family already has psoriasis. Some studies suggest that people who develop psoriatic arthritis may have recently recovered from a viral or bacterial infection, or an injury. People with HIV/AIDS may have particularly severe psoriatic arthritis.

Approximately 70% of people with psoriatic arthritis already have skin symptoms of psoriasis. Roughly 15% develop joint symptoms before skin symptoms, and another 15% have joint and skin symptoms simultaneously.

What Causes Psoriatic Arthritis?

Like psoriasis, psoriatic arthritis is caused by immune system malfunctions. Cells that are meant to fight outside invaders (like viruses or bacteria) turn against your skin, joints and tendons instead.

What are Its Symptoms?

If you have psoriatic arthritis, you're likely to notice:

  • Stiff, painful, red and swollen joints
  • Pain and swelling over areas where tendons attach muscles to bones
  • Severe heel pain
  • Fatigue
  • Swelling of fingers or toes, or both -- commonly referred to as the "sausage digit"
  • Increased pain, stiffness and tiredness in the morning
  • Ridges, pits and yellow-orange discoloration of fingernails and toenails
  • Separation of the nails from their nail beds
  • Red, painful eyes
  • Anemia (low blood levels of iron)
  • Mood changes

Symptoms of psoriatic arthritis can wax and wane. Some patients enjoy several symptom-free years between flares-ups. Others have continual symptoms that grow progressively more severe.

In children, the symptoms of psoriatic arthritis may occur years before skin symptoms. Finger swelling is a frequent symptom in children. Skin symptoms appear in about 33% of children with psoriatic arthritis by age 15.

How is Psoriatic Arthritis Diagnosed?

There's no definitive test for psoriatic arthritis. Your doctor will consider several factors in making a diagnosis, including whether you have characteristic symptoms, and if blood tests, x-rays or MRI results rule out other explanations, such as gout or rheumatoid arthritis. The diagnosis may be fairly straightforward for those who already have psoriasis of the skin, but less so if joint symptoms appear first. Early in the disease, x-rays don't show anything particularly distinctive, but later in the illness they often reveal characteristic features.

How is it Treated?

There's no cure for psoriatic arthritis. Treatment seeks to reduce inflammation, slow joint destruction and minimize symptoms. In milder cases, aspirin-containing or nonsteroidal anti-inflammatory drugs -- like Motrin (ibuprofen) -- may suffice. Biologic agents such as Humira (adalimumab), Remicade (infliximab), or  Enbrel (etanercept) are currently used as first-line treatments for more severe cases of psoriatic arthritis. Other treatment for severe symptoms include some of the same drugs used in treating rheumatoid arthritis, such as gold compounds, Rheumatrex (methotrexate), Sandimmune (cyclosporine), and Azulfidine (sulfasalazine).

Psoralen ultraviolet A light (PUVA) therapy involves taking the drug psoralen by mouth -- or by IV, in some cases -- and exposing your skin to ultraviolet light of a particular wavelength A. Steroid injections directly into affected joints may also provide relief.

You should also ask your doctor whether physical therapy would be helpful. Carefully planned exercise routines can strengthen muscles, improve your energy level and boost your sense of well-being.

Sources:

Gladman D.D. "Psoriatic Arthritis." Clinical Dermatology. Fourth ed. Ed. T.P. Habif. St. Louis: Mosby, 2004. 1156-1162.

Gordon K.B. "The Treatment of Psoriasis and Psoriatic Arthritis: An Interdisciplinary Approach." Journal of the American Academy of Dermatology. 54.3. Mar. 2006: S85-91.
<http://www.eblue.org/article/S0190-9622(05)04573-1/fulltext> (subscription)

Gottlieb A. "Guidelines of Care for the Management of Psoriasis and Psoriatic Arthritis: Section 2. Psoriatric Arthritis: Overview and Guidelines of Care for Treatmenet with an Emphasis on the Biologics." Journal of the American Academy of Dermatology. 58.5. May 2008: 851-64.
<http://www.eblue.org/article/S0190-9622(08)00273-9/fulltext> (subscription)

Mease P. "Current Treatment for Psoriatic Arthritis and other Spondyloarthritides." Rheumatic Disease Clinics of North America. 32.1. Dec. 2006: 11-20.
<http://www.rheumatic.theclinics.com/article/S0889-857X(07)70004-2/pdf> (subscription)

Mercier L.R. "Arthritis, Psoriatic." Ferri's Clinical Advisor 2008. First ed. Ed. Fred Ferri. Philadelphia: Mosby Elsevier, 2008. 84.

"Questions and Answers about Psoriasis." National Institute for Arthritis and Musculoskeletal and Skin Diseases. May 2003. National Institutes of Health. 15 May 2005. <http://www.niams.nih.gov/Health_Info/Psoriasis/psoriasis_qa.pdf>

Weiss JE, Ilowite NT. "Juvenile Idiopathic Arthritis."/Rheumatic Disease Clinics of North America/33.3 (1 August 2007): 441-70.

LifeWire, a part of The New York Times Company, provides original and syndicated online lifestyle content. Rosalyn Carson-DeWitt, MD, works as a medical writer, editor, and consultant in Durham, NC. She served as editor-in-chief for two multi-volume MacMillan encyclopedias:  The Encyclopedia of Drugs, Alcohol, and Addictive Behavior and Drugs, Alcohol and Tobacco: Learning About Addictive Behavior. She worked on the 18th edition of the Merck Manual of Diagnosis and Therapy, and has written thousands of print and online articles for healthcare providers and consumers.

©2014 About.com. All rights reserved.

We comply with the HONcode standard
for trustworthy health
information: verify here.