Psoriatic Arthritis Clinical Presentation

Updated: Jan 24, 2022
  • Author: Anwar Al Hammadi, MD, FRCPC; Chief Editor: Herbert S Diamond, MD  more...
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Psoriasis appears to precede the onset of psoriatic arthritis in 60-80% of patients (occasionally by as long as 20 years, but usually by less than 10 years). However, in as many as 15-20% of patients, arthritis appears before the psoriasis, in which case a family history may reveal a hereditary pattern of psoriasis. Occasionally, arthritis and psoriasis appear simultaneously.

In some cases, patients may experience only stiffness and pain, with few objective findings. In a patient who presents with musculoskeletal symptoms without a history of psoriasis, the diagnosis can be suspected based on a family history of psoriasis and the pattern of arthritis.

In most patients, the musculoskeletal symptoms are insidious in onset, but an acute onset has been reported in one third of all patients.

Factors that increase the risk of a patients with psoriasis developing arthritis in their lifetime include the presence of nail lesions, as well as more extensive skin involvement.

One third of patients may develop inflammatory ocular symptoms reminiscent of reactive arthritis (previously termed Reiter syndrome).

Involvement of axial joints occurs in 25-70% of patients with psoriatic arthritis, and 5% patients have exclusive axial involvement. Common symptoms in these cases include back pain that improves with activity but worsens with rest, and morning stiffness lasting > 30 minutes). [58]

Eder et al reported that psoriatic arthritis has a preclinical phase that presages diagnosis of the disease. [59, 60] During this phase, patients have nonspecific musculoskeletal symptoms, including joint pain, fatigue, and stiffness. In their prospective cohort study of 410 patients with psoriasis, 57 of whom developed psoriatic arthritis, the following symptoms predicted the development of psoriatic arthritis:

  • Arthralgia in women (hazard ratio [HR] 2.59, P = 0.02)
  • Heel pain (HR 4.18, P = 0.02)
  • High fatigue score (HR 2.36, P = 0.007)
  • High stiffness score (HR 2.03, P = 0.045)
  • Increase from baseline in fatigue score (HR 1.27, P = 0.001), pain score (HR 1.34, P <  0.001), and stiffness score (HR 1.21, P = 0.03)
  • Worsening in physical function score (HR 0.96, P = 0.04)

Physical Examination

Psoriatic arthritis may be present with or without obvious skin lesions, with minimal skin involvement (eg, scalp, umbilicus, intergluteal cleft), or with only nail malformations. Less joint tenderness possibly occurs with psoriatic arthritis than with rheumatoid arthritis (RA).

Recognition of the patterns of joint involvement seen in psoriatic arthritis, as follows, is essential to the diagnosis:

  • Asymmetrical oligoarticular arthritis
  • Symmetrical polyarthritis
  • Distal interphalangeal arthropathy
  • Arthritis mutilans (seen in the image below)
  • Spondylitis with or without sacroiliitis
Patient with psoriatic arthritis involving the joi Patient with psoriatic arthritis involving the joints and skin displays features of arthritis mutilans with distal interphalangeal joint destruction causing a deformity and compromise to function.

As in other spondyloarthropathies, the condition termed enthesopathy or enthesitis, reflecting inflammation at tendon or ligament insertions into bone, may be seen in psoriatic arthritis. Enthesopathy is observed more often at the attachment of the Achilles tendon and the plantar fascia to the calcaneus with the development of insertional spurs.

Dactylitis with sausage digits (seen in the image below) occurs in as many as 35% of patients. Diagnosis is also suggested by asymmetrical joint involvement, dactylitis, the absence of RF, and distal interphalangeal (DIP) joint involvement in the absence of osteoarthritis. When localized to the foot or toe, the symptoms of psoriatic arthritis may be mistaken for gout.

Psoriatic arthritis showing nail changes, distal i Psoriatic arthritis showing nail changes, distal interphalangeal joint swelling, and sausage digits.

Skin involvement

The following skin lesions may be seen in the context of psoriatic arthritis:

In one study, as previously mentioned, arthritis was noted more frequently in patients with severe skin disease.

In patients presenting with an undefined seronegative polyarthritis, looking for psoriasis in hidden sites, such as the scalp (where psoriasis frequently is mistaken for dandruff), perineum, intergluteal cleft, and umbilicus is extremely important.

Nail involvement

Nails are involved in 80% of patients with psoriatic arthritis but in only 20% of patients with uncomplicated psoriasis, with nail involvement frequently seen at the onset when skin and joint disease begin simultaneously. The following changes in the nails support the diagnosis of psoriatic arthritis [61] :

  • Beau lines
  • Leukonychia
  • Onycholysis
  • Oil spots
  • Subungual hyperkeratosis
  • Splinter hemorrhages
  • Spotted lunulae
  • Transverse ridging
  • Cracking of the free edge of the nail
  • Uniform nail pitting: A direct correlation exists between the number of pits and their diagnostic significance (see the image below)
  • Left, typical appearance of psoriasis, with silver Left, typical appearance of psoriasis, with silvery scaling on a sharply marginated and reddened area of skin overlying the shin. Right, thimblelike pitting of the nail plate in a 56-year-old woman who had suffered from psoriasis for the previous 23 years. Nail pitting, transverse depressions, and subungual hyperkeratosis often occur in association with psoriatic disease of the distal interphalangeal joint. Courtesy of Ali Nawaz Khan, MBBS.

Severe, deforming arthritis of the hands and feet is frequently associated with extensive nail involvement.

Involvement of DIP joints correlates moderately well with psoriasis in adjacent nails, although this is not an invariable association. In fact, psoriatic nail changes may be a solitary finding in patients with psoriatic arthritis.

Fungal infection of the nails is the main consideration in the differential diagnosis in a patient with a seronegative polyarthritis.

Extra-articular features

Extra-articular features are observed less frequently in patients with psoriatic arthritis than in those with RA. In patients with psoriatic arthritis, synovitis has a predilection for the flexor tendon sheath, with sparing of the extensor tendon sheath; both tendon sheaths are commonly involved in persons with RA.

Subcutaneous nodules are rare in patients with psoriatic arthritis. If nodules are present in a patient who has psoriasis and arthritis, particularly if the RF titer is positive, they suggest the coincidental occurrence of psoriasis and RA.

Ocular involvement may occur in 30% of patients with psoriatic arthritis, including conjunctivitis in 20% of patients and acute anterior uveitis in 7% of them. In patients with uveitis, 43% have sacroiliitis and 40% are HLA-B27–positive. Scleritis and keratoconjunctivitis sicca are rare. Possible ocular findings also include iritis.

Inflammation of the aortic valve root, which may lead to insufficiency, has been described in 6 patients with psoriatic arthritis and is similar to that observed more frequently in persons with ankylosing spondylitis or reactive arthritis. Occasionally, patients with psoriatic arthritis may develop secondary amyloidosis.