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RiittaLuosujärvi

Psoriatic Arthritis

Essentials

  • Psoriatic arthritis is a progressive, multiform, chronic, immunological, inflammatory disease of joints and the whole organ system that is often familial and may lead to destruction of joints.
  • Starting treatment without delay may improve the patient's long term prognosis.
  • Treatment aims at reducing the systemic inflammation and at eliminating both skin and joint symptoms.
  • The patient should be motivated for treatment from the very beginning.
  • The treatment of psoriatic arthritis depends on the extent of symptoms, radiological progression, and the activity of the dermatological disease.
  • The treatment of psoriatic arthritis is based on methotrexate and good analgesia.
  • Biological treatment and other selective antirheumatic drugs can be used, as necessary.
  • The risk of arterial disease, diabetes and potential depression associated with psoriatic arthritis should always be taken into account when planning the treatment.
  • Often, the patient is treated jointly by a rheumatologist and a dermatologist.

Epidemiology

  • The prevalence of cutaneous psoriasis among the European and North-American population is 1.5-3%. In an unselected population, the prevalence of psoriatic arthritis is 0.16-0.25%.
    • At the onset of psoriasis, 2.4% of patients have psoriatic arthritis.
    • The risk of psoriatic arthritis increases with increasing duration of psoriasis, and 10-20% of patients with skin psoriasis also have psoriatic arthritis.
    • In severe psoriasis, the risk of arthritis is 40-50%.
  • Psoriatic arthritis may occur without skin symptoms.
  • Psoriatic arthritis of small joints is equally common in men and women but the disease with spondylarthritis is more common in men.
  • The incidence of psoriatic arthritis has increased during the last few decades.
  • Psoriasis is a chronic, complex, immune-mediated inflammatory disease. People with psoriasis and psoriatic arthritis have many associated disorders, such as cardiovascular disorders, diabetes, IBD and depression. Particular attention should be paid to their treatment. The patient must be treated holistically.

History, symptoms and findings

  • Susceptibility to the disease is determined by genetic factors.
    • Patients often have a family history of psoriasis. In particular, there is a hereditary predisposition associated with psoriasis that starts before the age of 40.
    • HLA-B27-positive patients often have sacroiliitis or spondylarthritis Axial Spondyloarthritis and Ankylosing Spondylitis.
    • Psoriatic arthritis as such is not clearly associated with HLA-B27 positivity.
  • Psoriatic arthritis should be suspected if a patient with cutaneous psoriasis develops symptoms of arthritis and clinical findings consistent with psoriatic arthritis.
    • However, cutaneous psoriasis does not exclude diseases such as rheumatoid arthritis Rheumatoid Arthritis.

Clinical findings typical for psoriatic arthritis

  • Joint symptoms are multiform and often asymmetric.
  • Painful joints and tenderness and inflammation of tendon insertions (enthesitis), such as inflammation in the heel bone at the insertion site of the Achilles tendon commonly occur.
    • Especially pain is a significant difference compared to for example rheumatoid arthritis.
  • Asymmetric inflammation of a few joints
  • Polyarthritis
    • May at first clinically resemble rheumatoid arthritis.
    • Both rheumatoid factor (RF) and serum citrullinated peptide antibodies are usually negative.
  • Inflammation of DIP joints (often PIP + DIP), often associated with typical nail changes ( 1 2 3). It may be very painful.
  • Dactylitis (sausage finger or toe)
  • Asymmetric sacroiliitis and spondylitis are common in patients with spondylarthritis.
  • Typically callus formation on bone surfaces, i.e. in the periosteum
  • Polyarthritic disease eroding bone, and a form of disease causing swelling of the whole limb are rare.
  • Uveitis can be seen in patients with psoriatic arthritis.

Diagnosis

  • The diagnosis is clinical; there are no exact diagnostic criteria.
  • The diagnostic criteria of the CASPAR working group can be used to define the disease. However, it should be remembered that they were made for use in research.
  • Psoriatic arthritis cannot be diagnosed based on laboratory tests.
    • Patients with psoriatic arthritis may have increased plasma urate concentration in the absence of gout.
    • ESR and CRP may be either elevated or normal.
    • Rheumatoid factor and anti-CCP antibodies may be exceptionally increased.
  • Changes possibly seen in X-ray can be used for diagnosis.
    • Periosteal callus formation
    • Bone erosion
    • Complete fusion of joints
    • 'Pencil-in-cup' changes in small phalangeal joints
    • Unilateral sacroiliitis
    • Asymmetric bulky syndesmophytes, 'jug handles', between vertebrae
    • In the mutilating form of the disease, the middle phalanx, for example, may dissolve completely.
    • Changes in X-rays may appear early.
  • Articular ultrasonography will show thickened synovial membranes with increased blood flow, increased amounts of synovial fluid, increased blood flow in the periosteum, callus formation, erosions as well as tendonitis and enthesites.
  • Magnetic resonance imaging (MRI) can be used to confirm vertebral and sacroiliac (SI) joint inflammation before changes can be seen in conventional X-ray. MRI is important also in the assessment of the inflammation and changes in large joints, such as the hip joints. MRI also reveals enthesites well. The need for MRI will be defined by a specialist.

Treatment Methotrexate for Psoriatic Arthritis

  • In a fresh psoriatic arthritis, treatment that aims at remission may significantly improve the status of the joints.
  • Traditional synthetic disease-modifying antirheumatic drugs (sDMARD), anti-inflammatory analgesics and biological drugs and other selective antirheumatic drugs are used for treatment.
  • Treatment depends on assessment by patient and doctor, the number of inflamed joints, radiological progress and degree of disease of the skin.
  • If, however, there are several symptomatic joints or the disease is progressive, methotrexate, or if it is contraindicated sulphasalazine, is used already at an early stage.
  • A mild psoriatic arthritis is treated with NSAIDs and local intra-articular glucocorticoid injections.
    • In joints, the effectiveness of injection treatment is better than in enthesites.
    • If local glucorticoid injections do not suppress the arthritis adequately, the first-line therapy is methotrexate.
  • General remarks
    • Anti-inflammatory analgesics are used particularly in the beginning of the disease; for the form of disease with spondylarthritis and enthesitis, treatment may be needed for several years.
    • Methotrexate is the primary sDMARD for psoriatic arthritis. If methotrexate is contraindicated, sulfasalazine is chosen. Methotrexate often also alleviates cutaneous symptoms.
    • Sudden withdrawal of high-dose systemic glucocorticoids may aggravate cutaneous psoriasis.
    • Ciclosporin is may be effective in the treatment of both skin and joint symptoms, but is is not suitable for long-term treatment.
    • Intra-articular glucocorticoid injections are usually effective.
    • Biological drugs (bDMARD) alleviate both skin and joint inflammation.
  • According to clinical experience, the prognosis of psoriatic arthritis is often better than that of rheumatoid arthritis, and treatment started without delay may predict a milder clinical course.

Organization of care

  • Patients, whose joint disease is stable, are usually followed-up within primary health care. Also the screening and treatment of associated diseases can be carried out in primary health care.
  • In active and progressive disease, the treatment of psoriatic arthritis is often carried out in cooperation by primary health care, a dermatologist and a rheumatologist.
  • Without consulting a specialist, a physician in primary health care may provide symptomatic treatment and intra-articular glucocorticoid injections for mild psoriatic arthritis.
    • Mild disease usually causes joint pain or rarely inflammation of individual joints.
  • Patients to be referred for an assessment by a rheumatologist include those with fresh polyarthritis (inflammation of more than 4 joints), with a disease that resembles ankylosing spondylitis or with a prolonged inflammation of a few (less than 4) joints that responds poorly to NSAIDs and local glucocorticoid injections or when X-rays show progressive changes.
    • Later on, treatment can usually be provided either entirely in primary health care or the responsibility shared with specialized care.
    • Severe forms of disease are treated in specialized care.
  • Children with psoriatic arthritis should be treated in specialized care.
  • Before pregnancy, a safe pharmacotherapy to be used during pregnacy should be planned and, as required, a rheumatologist consulted.

Follow-up

  • Results of treatment should be followed up and assessed regularly.
  • Full care of the patients should include screening and careful treatment of diseases associated with psoriasis.
  • The medication needs to be monitored by safety tests. See locally available guidance.
  • The special features of biological medicines (bDMARD) and other selective antirheumatic drugs should be kept in mind in primary health care, too.
  • Measurement tools are available for following up and assessing response to treatment.

    References

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    • Mehta NN, Azfar RS, Shin DB, et al. Patients with severe psoriasis are at increased risk of cardiovascular mortality: cohort study using the General Practice Research Database. Eur Heart J 2010;31(8):1000-6. [PubMed]
    • Prey S, Paul C, Bronsard V, et al. Assessment of risk of psoriatic arthritis in patients with plaque psoriasis: a systematic review of the literature. J Eur Acad Dermatol Venereol 2010;24 Suppl 2():31-5. [PubMed]
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