Clinical Manifestations of Psoriatic Arthritis
Psoriatic arthritis is a rheumatoid factor negative spondyloarthropathy that generally affects 3 principle areas: the entheses of bones (i.e., the points at which tendons, ligaments, or muscles insert into bone), the synovium, and the sacroiliac joints.11421 Like other types of arthritis, psoriatic arthritis is characterized by swelling, inflammation, warmth, and erythema of the affected joint. It is usually associated with psoriatic skin lesions and generally develops years after the onset of skin disease. This process may occur in either an oligoarticular or polyarticular fashion and commonly involves the distal joints, distinguishing it from rheumatoid arthritis (RA). The distribution of joint involvement in psoriatic arthritis tends to occur in a ray pattern, so that all the joints of a single digit are more likely to be affected than the same joints on both sides as in rheumatoid arthritis.11398 Psoriatic arthritis can affect any joint of the body, including the peripheral joints (e.g., distal interphalangeal joints) and/or the axial joints (spine and sacroiliac joints). Periarticular structures may also be affected, resulting in tenosynovitis, dactylitis ("sausage digit"), and enthesitis. The hands, arms, hips, legs and feet are commonly affected.11389
A major distinction between psoriatic arthritis and rheumatoid arthritis is that up to 80% of patients with rheumatoid arthritis are seropositive for rheumatoid factor, compared to only 10% of patients with psoriatic arthritis. In addition, psoriatic arthritis may affect the spine, while rheumatoid arthritis does not, and there is no gender predilection for psoriatic arthritis, although more females than males are affected with rheumatoid arthritis.11643
Figure 3099 – Psoriatic Arthritis
Winchester R. Psoriatic arthritis. In: Wolff K, Goldsmith LA, Katz SI, Gilchrest BA, Paller AS, Leffell DJ, eds. Fitzpatrick’s Dermatology in General Medicine. 7th ed. New York, NY; McGraw-Hill; 2008,194-207 (chap 19). Figure 19-1, Page 195. Copyright McGraw-Hill Companies Inc.
Some figures may not display clearly when rendered as a PDF or printed.
The following is a list of characteristic and supporting features of psoriatic arthritis, as well as a list of exclusionary features of the disease11421 :
Characteristic features
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Psoriasis present
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Enthesitis
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Dactylitis
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Onychodystrophy
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Distal interphalangeal joint involvement
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Juxtaarticular new bone formation
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Sacroiliitis and/or spondyloarthritis
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Isolated involvement of the joints of 1 ray (e.g., distal interphalangeal, proximal interphalangeal, monocyte chemotactic protein)
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Insidious appearance of ankylosed joints (e.g., hallux rigidus)
Supporting Features
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In the absence of documented psoriasis, a convincing history of psoriasis and/or a family history positive for psoriasis
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Peripheral arthritis
Exclusionary Features
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Fibromyalgia
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Seronegative or seropositive rheumatoid arthritis
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Intercurrent arthritides (e.g., Lyme disease)
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Repetitive motion-induced musculoskeletal syndromes
Although the presence of psoriasis is a definitive hallmark of psoriatic arthritis, it is not an absolute requirement for its diagnosis. Instead, a previous history of psoriasiform lesions or a family history of psoriasis in conjunction with other signs and symptoms of psoriatic arthritis can be enough to document the presence of the disease.11421 In fact, there have been cases of undifferentiated spondylitis with joint involvement similar to that of psoriatic arthritis, giving rise to the term psoriatic arthritis sine psoriasis.11421 In these cases, the distinguishing feature has been the absence of psoriasis.
Skin Manifestations
Skin disease usually appears 10-20 years before the onset of psoriatic arthritis. However, in a small percentage of patients, it is possible for arthritis to appear first, causing difficulty in diagnosing psoriatic arthritis.11396 Several patterns of psoriasis have been associated with psoriatic arthritis, including the following: vulgaris, eruptive, erythrodermic, and pustular.11429 In cases that are difficult to determine, a patient must be thoroughly examined for psoriatic lesions, as they may be located in hidden areas of the scalp, perineum, or umbilicus.11396 In cases such as these, the following criteria may be used to aid in the diagnosis of psoriasis11430 :
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Psoriasis of the scalp must be palpable.
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Presumed scalp psoriasis, simulating dandruff, must exhibit normal skin between plaques.
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In the presence of eczema or seborrheic states, lesions other than classic plaques cannot be accepted as psoriasis.
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Toenail lesions alone cannot be accepted as evidence of psoriasis.
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In the absence of psoriasis elsewhere, only classic nail changes (i.e., pitting, onycholysis, and discoloration of the lateral nail edge) can be accepted as unequivocal psoriasis. In such cases, fungal infection should be excluded by culture and microscopy.
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Flexural lesions can be accepted only if they have the classic appearance of a psoriatic plaque. In such cases, microscopy of scrapings must be done to exclude tinea or Candida infection.
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Pustular lesions of the palms and soles are not acceptable unless accompanied by classic skin or nail lesions elsewhere.
Enthesitis
Enthesitis may present in several different ways. A patient may present with subtle pain, such as isolated, nondescript foot pain, tennis elbow in the non-dominant hand, or posterior tendonitis. On the other hand, widespread, symmetric enthesitis may be present and is more clearly associated with the disease. This widespread presentation differentiates enthesitis from the classic pain seen in a posttraumatic or occupational tendon injury, which would result in pain in the dominant hand or arm.11421
Nail Manifestations
Nail disease is a common manifestation of psoriatic disease. Psoriatic disease can refer to psoriasis alone or psoriatic arthritis, and nail involvement is generally more common in patients with psoriatic arthritis with up to 85% occurrence. Manifestations of nail disease include nail pitting and crumbling, Beau’s lines (ridging), subungual hyperkeratosis and onycholysis, leukonychia, salmon patches, erythematous patches of the lunula, and ectatic tortuous capillaries that resemble splinter hemorrhages.11421
Abnormal nail findings do not necessarily signify psoriatic disease, and it is important to consider fungal and bacterial nail infections in the differential diagnosis. To rule out fungal infections, nail clippings can be examined for the presence of fungus using preparations of potassium hydroxide.11396
Extraarticular Manifestations
Other, less common extraarticular manifestations of psoriatic arthritis include potential ocular involvement and renal abnormalities.
Ocular involvement, especially conjunctivitis, may be seen in roughly 25% of patients, while iritis is seen in approximately 5% of patients. Conjunctivitis is usually treatable with symptomatic therapy, although iritis must be detected early and appropriate therapy initiated.11421 The presentation of chronic bilateral uveitis is mainly seen in HLA-B27 – positive males and may be a presenting factor of the disease. Worldwide, the HLA-B27 genetic marker is found in between 4% - 39% of patients with psoriatic arthritis.11396
Psoriatic Arthritis Subtypes
There are 5 subtypes of psoriatic arthritis: asymmetric arthritis, symmetric arthritis, distal interphalangeal predominant, spondylitis, and arthritis mutilans.
Asymmetric Arthritis
Asymmetric arthritis, or oligoarticular asymmetrical arthritis, occurs in up to 70% of patients with psoriatic arthritis and is characterized by the presence of dactylitis and/or monoarthritis in 4 or fewer joints. This form of psoriatic arthritis is usually mild but may cause disabling disease in some individuals.
Asymmetric arthritis can affect any joint, including the knee and wrist, and does not occur on both sides of the body. Affected joints are typically erythematous, tender, and warm, though the pain is generally responsive to medical therapy.11389, 11390
The most characteristic pattern of asymmetric arthritis usually involves scattered distal interphalangeal (DIP), proximal interphalangeal (PIP), metacarpophalangeal (MCP), and metatarsophalangeal (MTP) joint involvement. Commonly there is involvement of an MCP joint with an associated flexor tenosynovitis, causing the aforementioned "sausage digit."11396
Figure 3090 – Asymmetric Polyarthritis Resembling Rheumatoid Arthritis in a Patient With Psoriasis
Bennett RM. Psoriatic arthritis. In: Koopman WJ, Moreland LW, eds. Arthritis and Allied Conditions. 15th ed. 2005;1357-1374 (chap 65). Figure 65.2, Page 1360. Copyright Lippincott Williams & Wilkins. All rights reserved.
Some figures may not display clearly when rendered as a PDF or printed.
Figure 3092 – Psoriatic Arthritis Involving the Metacarpophalangeal and Proximal Interphalangeal Joints of the Index Finger With an Associated Flexor Tenosynovitis
Bennett RM. Psoriatic arthritis. In: Koopman WJ and Moreland LW, eds. Arthritis and Allied Conditions. 15th ed. 2005;1357-1374 (chap 65). Figure 65.4, Page 1360. Copyright Lippincott Williams & Wilkins. All rights reserved.
Some figures may not display clearly when rendered as a PDF or printed.
Symmetric Arthritis
Symmetric arthritis, or symmetrical polyarthritis, is similar to rheumatoid arthritis, but it is generally milder and involves less deformity. It may occur in up to 15% of patients with psoriatic arthritis. Symmetric arthritis typically affects multiple symmetric pairs of joints (up to 5 joints), with evidence of erosion and metacarpophalangeal joint involvement. This form of the disease can also be disabling.11389, 11390
Figure 3091 – Long-Standing Psoriatic Arthritis With a Symmetric Distribution
Bennett RM. Psoriatic arthritis. In: Koopman WJ, Moreland LW, eds. Arthritis and Allied Conditions. 15th ed. 2005;1357-1374 (chap 65). Figure 65.3, Page 1360. Copyright Lippincott Williams & Wilkins. All rights reserved.
Some figures may not display clearly when rendered as a PDF or printed.
Distal Interphalangeal Predominant
Distal interphalangeal predominant, also called the classic type of psoriatic arthritis, occurs in about 5% of people with psoriatic arthritis. This form involves the distal joints of the fingers and toes, is associated with severe nail psoriasis, and can present similarly to osteoarthritis. Osteoarthritis, also known as degenerative arthritis or wear-and-tear disease, presents gradually and often appears after periods of inactivity or overuse of a joint.11389, 11390, 11744
Spondylitis
Inflammation of the spinal column, or spondylitis, occurs in approximately 5% of patients with psoriatic arthritis. Larger numbers of patients experience inflammation with stiffness of the neck, lower back, and sacroiliac or spinal vertebrae.11389 Sacroiliitis may also be present in patients with psoriatic arthritis, but neither spondylitis nor sacroiliitis tend to be presenting features of the disease. Instead, these manifestations of the disease typically occur after several years of peripheral joint disease involvement.11396
Figure 3094 – Psoriatic Arthritis With Axial Involvement
Bennett RM. Psoriatic arthritis. In: Koopman WJ, Moreland LW, eds. Arthritis and Allied Conditions. 15th ed. 2005;1357-1374 (chap 65). Figure 65.15, Page 1367. Copyright Lippincott Williams & Wilkins. All rights reserved.
Some figures may not display clearly when rendered as a PDF or printed.
Arthritis Mutilans
Arthritis mutilans, a severe and destructive form of arthritis, is strongly suggestive of psoriatic arthritis; however, it appears to affect 5% or less of this patient population. Frequently, the neck or lower back may be involved.11389
Figure 3089 – Severe Resorptive Arthropathy Resulting in Arthritis Mutilans
Bennett RM. Psoriatic arthritis. In: Koopman WJ, Moreland LW, eds. Arthritis and Allied Conditions. 15th ed. 2005;1357-1374 (chap 65). Figure 65.1, Page 1360. Copyright Lippincott Williams & Wilkins. All rights reserved.
Some figures may not display clearly when rendered as a PDF or printed.
Content on this page was last reviewed on July 31, 2008.
Content on this page was last changed on March 19, 2009.
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| 11390. | Landells I, MacCallum C, Khraishi M. The role of the dermatologist in identification and treatment of the early stages of psoriatic arthritis. Skin Therapy Letter website. www.skintherapyletter.com/2008/13.4/2.html . Accessed September 24, 2008. |
| 11396. | Bennett RM. Psoriatic arthritis. In: Koopman WJ, Moreland LW, eds. Arthritis and Allied Conditions . 15th ed. Philadelphia, PA: Lippincott, Williams and Wilkins; 2005:1357-1374. |
| 11398. | Gladman DD, Antoni C, Mease P, Clegg DO, Nash P. Psoriatic arthritis: epidemiology, clinical features, course, and outcome. Ann Rheum Dis . 2005;64(Suppl 2):ii14-ii17. |
| 11421. | Winchester R. Psoriatic arthritis. In: Wolff K, Goldsmith LA, Katz SI, Gilchrest BA, Paller AS, Leffell DJ, eds. Fitzpatrick’s Dermatology in General Medicine . 7th ed. New York, NY: McGraw-Hill; 2008:194-207. |
| 11429. | Biondi-Oriente C, Scarpa R, Pucino A, Oriente P. Psoriasis and psoriatic arthritis. Dermatological and rheumatological co-operative clinical report. Acta Derm Venereol Suppl (Stockh) . 1989;146:69-71. |
| 11430. | Baker H. Epidemiological aspects of psoriasis and arthritis. Br J Dermatol . 1966;78(5):249-261. |
| 11643. | Gladman DD. Natural history of psoriatic arthritis. Baillieres Clin Rheumatol . 1994;8(2):379-394. |
| 11744. | Eustice C, Eustice R. Arthritis: Osteoarthritis - Fast Facts. About.com website. http://arthritis.about.com/od/oa/p/osteoarthfacts.htm?p=1 . Accessed December 18, 2008. |
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