Lab Studies:

• No specific diagnostic tests are available for psoriatic arthritis. Diagnosis of the disease is made based on clinical and radiologic criteria in a patient with psoriasis.

• Immunoglobulin M (IgM) rheumatoid factor in serum usually is absent. However, in 33% of patients, immunoglobulin G (IgG) antiglobulins have been detected in serum. When IgM rheumatoid factor positivity is studied in a group of patients with psoriatic arthritis and a similar comparison is undertaken in an age-matched and sex-matched normal population, rheumatoid factor positivity generally is found to be comparable in both groups.

• The erythrocyte sedimentation rate may be elevated in patients with active psoriatic joint disease, but elevations higher than 100 mm/h (Westergren method) are uncommon. Severe skin and joint disease may be associated with a mild normochromic normocytic anemia and leukocytosis. Acute phase reactants, such as alpha2-macroglobulin, may be increased.

• Antinuclear antibody titers in psoriatic arthritis do not differ from those of age-matched and sex-matched control populations. In 10-20% of patients with generalized skin disease, the serum uric acid concentration may be increased and, on occasion, may predispose to acute gouty arthritis. Low levels of circulating immune complexes have been detected in 56% of patients with psoriatic arthritis but do not appear to parallel disease activity.

• The associations of psoriatic arthritis with HLA-B17, HLA-B13, and HLA-B27 were described under Genetics. Serum immunoglobulin A levels are increased in two thirds of patients with psoriatic arthritis and in one third of patients with psoriasis. Levels of IgM tend to increase with severe disease, but IgG levels usually are not elevated.

• Synovial fluid is inflammatory, with cell counts ranging from 5,000-15,000/mm³ and with more than 50% of cells being polymorphonuclear leukocytes. Within the synovium, the infiltrate consists predominantly of T lymphocytes. Synovial fluid complement levels are either within reference ranges or increased, and glucose levels are within reference ranges.

Imaging Studies:

• Radiological features have helped to distinguish psoriatic arthritis from other causes of polyarthritis. In general, the common subtypes of psoriatic arthritis, such as asymmetric oligoarthritis and symmetric polyarthritis, tend to result in only mild erosive disease. Early bony erosions occur at the cartilaginous edge, and cartilage initially is preserved with maintenance of a normal joint space.

• Juxtaarticular osteopenia, which is a hallmark of rheumatoid arthritis, is minimal in psoriatic arthritis. Asymmetric erosive changes in small joints of the hands and feet are typical of psoriatic arthritis and have a predilection (in decreasing order) for DIP, proximal interphalangeal (PIP), metatarsophalangeal, and metacarpophalangeal (MCP) joints.

• Erosive disease frequently occurs in patients with either DIP involvement or progressive deforming arthritis and may lead to subluxation and, less commonly, bony ankylosis of the joint. Erosion of the tuft of the distal phalanx, and even the metacarpals or metatarsals, can progress to complete dissolution of the bone. Although this form of acroosteolysis is not diagnostic, it is very suggestive of psoriatic arthritis. The pencil-in-cup deformity observed in the hands and feet of patients with severe joint disease usually affects the DIP joints but also may involve the PIP joints.

• CT scan of the sacroiliac joint may be a sensitive method of visualizing involvement in patients with spondylitis or sacroiliitis.

• Recent studies have indicated that MRI may be a sensitive method for demonstrating typical enthesopathic pathology of psoriatic arthritis, particularly in the hands and feet.

Other Tests:

• Traditional methods of monitoring patients with rheumatic conditions include clinical assessment for joint inflammation or damage and radiographic evaluations. The radiologic scoring methods for evaluating peripheral joints in psoriatic arthritis were developed for patients with rheumatoid arthritis. A study validated the original Steinbrocker method, a modified Steinbrocker method, and the Larsen method for assessment of radiographs in patients with psoriatic arthritis. The latter 2 methods now can be used to assess disease progression in patients with psoriatic arthritis.

TREATMENT

Medical Care: The treatment of psoriatic arthritis is directed at controlling the inflammatory process. Although no clear correlation exists between the skin and joint inflammation in every patient, the skin and joint aspects of the disease often must be treated simultaneously.

Initial treatment is composed of nonsteroidal anti-inflammatory drugs (NSAIDs) for joint disease and topical therapies for the skin. In many patients, this approach is sufficient to control disease manifestations, although some patients have a worsening of psoriasis with NSAIDs. In these patients, a drug belonging to a different family of NSAIDs should be used.

• Intraarticular injection of entheses or single inflamed joints with corticosteroids may be particularly effective in some patients.

• Use disease-modifying drugs in individuals whose arthritis is persistent. If the skin disease is well controlled with topical medication, the joint disease can be treated with a variety of second-line or cytotoxic drugs.

• Intramuscular administration of gold has been used in the past but has been supplanted by newer disease-modifying antirheumatic drugs.

• In patients with severe skin inflammation, medications such as methotrexate (MTX), retinoic-acid derivatives, and psoralen plus ultraviolet light (PUVA) should be considered. These medications have been shown to work for both skin and joint manifestations.

• Sulfasalazine and cyclosporine are 2 second-line agents that have received particular attention in the management of psoriatic arthritis. Although these drugs may control the acute inflammation in psoriatic arthritis, they have not been helpful in arresting the progression of clinical and radiologic damage. Thus, the disease must be treated earlier or better drugs are necessary to prevent the damage that may ensue as a result of psoriatic arthritis.

• Cyclosporine appears to be an effective agent for the treatment of psoriasis and psoriatic arthritis.

• The major concern with cyclosporine is its toxicity, especially nephrotoxicity and hypertension. Combination therapy (eg, MTX/sulfasalazine, MTX/cyclosporine) may be more efficacious in some patients.

• Anti–TNF-alpha therapy, such as etanercept (Enbrel) and infliximab (Remicade) has reportedly been used in treatment of psoriatic arthritis. Etanercept was recently approved by the US Food and Drug Administration.

• Several other modalities have been tried in psoriatic arthritis, including vitamin D-3, bromocriptine, peptide T, and fish oils, but their efficacy remains to be proven.

• Antimalarials, particularly hydroxychloroquine (Plaquenil), usually are avoided in patients with psoriasis for fear of precipitating exfoliative dermatitis or exacerbating psoriasis. Two studies showed that these reactions did not occur in patients treated with hydroxychloroquine; therefore, it is used occasionally.

• Systemic corticosteroids usually are avoided because of possible rebound of the skin disease upon withdrawal.

Surgical Care: Arthroscopic synovectomy has been effective in treating severe chronic monoarticular synovitis. Because of the enhanced tendency for fibrosis associated with this therapy, anti-inflammatory and physical therapy measures aimed at improving range of motion are important adjuncts to this intervention. Joint replacement and forms of reconstructive therapy occasionally are necessary.

Diet: For people who have morning stiffness, the optimal time for taking an NSAID might be after the evening meal and again upon awakening. Taking NSAIDs with food can reduce stomach discomfort. All NSAIDs are capable of damaging the mucous layer and causing ulcers and GI bleeding when taken for long periods. Cyclooxygenase-2 (COX-2) selective inhibitors are associated with a lower incidence of gastric ulcers.

Activity:

• Exercise

• Exercise is an important part of total treatment to limit the pain and swelling of arthritis, which can make joints stiff and hard to move.

• A directed exercise program can improve movement, strengthen muscles to stabilize joints, improve sleep, strengthen the heart, increase stamina, reduce weight, and improve physical appearance.

• Rest

• Generally, a normal amount of rest and sleep is sufficient to decrease fatigue and reduce joint inflammation.

• In a very few people, psoriatic arthritis may cause extreme fatigue.

The treatment of psoriatic arthritis usually begins with NSAIDs. These include enteric-coated acetylsalicylic acid (ECASA), naproxen, indomethacin, ibuprofen, diclofenac, tolmetin, meloxicam, and other NSAIDs. ECASA and ibuprofen require frequent administration, whereas meloxicam and slow-release indomethacin may be administered in a once-daily routine, which may be preferred by some patients.

Indomethacin is the strongest of the available traditional NSAIDs, although it has significant adverse GI and CNS effects and a potential to increase blood pressure. It is best used for short-term (eg, acute) flares.

Several selective COX-2 inhibitors, such as celecoxib and rofecoxib, have been developed and may be the optimal agents in patients at risk for GI toxicity with NSAIDs. NSAIDs clearly control the mild inflammatory features of psoriatic arthritis; however, some NSAIDs may aggravate the skin psoriasis.

Drug Category: Nonsteroidal anti-inflammatories -- Have analgesic, anti-inflammatory, and antipyretic activities. Their mechanism of action may be inhibition of COX activity and prostaglandin synthesis. Other mechanisms also may exist, such as inhibition of leukotriene synthesis, lysosomal enzyme release, lipoxygenase activity, neutrophil aggregation, and various cell membrane functions.

Drug Name	Ibuprofen (Motrin, Ibuprin, Advil, Excedrin IB) -- DOC for patients with mild to moderate pain. Inhibits inflammatory reactions and pain by decreasing prostaglandin synthesis.
Adult Dose	400 mg PO q4-6h, 600 mg q6h, or 800 mg q8h while symptoms persist; not to exceed 3.2 g/d
Pediatric Dose	20-70 mg/kg/d PO divided tid/qid; start at lower end of dosing range and titrate; not to exceed 2.4 g/d
Contraindications	Documented hypersensitivity; peptic ulcer disease, recent GI bleeding or perforation, renal insufficiency, or high risk of bleeding
Interactions	Coadministration with aspirin increases risk of inducing serious NSAID-related adverse effects; probenecid may increase concentrations and, possibly, toxicity of NSAIDs; may decrease effect of hydralazine, captopril, and beta-blockers; may decrease diuretic effects of furosemide and thiazides; may increase PT when taking anticoagulants (instruct patients to watch for signs of bleeding); may increase risk of MTX toxicity; phenytoin levels may be increased when administered concurrently
Pregnancy	B - Usually safe but benefits must outweigh the risks.
Precautions	Category D in third trimester of pregnancy; caution in congestive heart failure, hypertension, and decreased renal and hepatic function; caution in coagulation abnormalities or during anticoagulant therapy

Drug Name	Diclofenac (Voltaren, Cataflam) -- Inhibits prostaglandin synthesis by decreasing activity of COX, which, in turn, decreases formation of prostaglandin precursors.
Adult Dose	Persistent night pain or morning stiffness: Up to 100 mg qhs may help to relieve pain; not to exceed total daily dose of 200 mg
Pediatric Dose	>12 years: Administer as in adults <12 years: Not established
Contraindications	Documented hypersensitivity; peptic ulcer disease, recent GI bleeding or perforation, renal insufficiency, and those at high risk of bleeding
Interactions	Coadministration with aspirin increases risk of inducing serious NSAID-related adverse effects; probenecid may increase concentrations and, possibly, toxicity of NSAIDs; may decrease effect of hydralazine, captopril, and beta-blockers; may decrease diuretic effects of furosemide and thiazides; may increase PT when taking anticoagulants (instruct patients to watch for signs of bleeding); may increase risk of MTX toxicity; phenytoin levels may be increased when administered concurrently
Pregnancy	B - Usually safe but benefits must outweigh the risks.
Precautions	Category D in third trimester of pregnancy; acute renal insufficiency, hyperkalemia, hyponatremia, interstitial nephritis, and renal papillary necrosis may occur; increases risk of acute renal failure in patients with preexisting renal disease or compromised renal perfusion; low WBC counts occur rarely and usually return to normal in ongoing therapy; discontinuation of therapy may be necessary if persistent leukopenia, granulocytopenia, or thrombocytopenia develops

Drug Name	Naproxen (Anaprox, Naprelan, Naprosyn, Aleve) -- For relief of mild to moderate pain. Inhibits inflammatory reactions and pain by decreasing activity of COX, which is responsible for prostaglandin synthesis.
Adult Dose	250-500 mg PO bid; may increase to 1.5 g/d for limited periods
Pediatric Dose	<2 years: Not established >2 years: 2.5 mg/kg/dose PO; not to exceed 10 mg/kg/d
Contraindications	Documented hypersensitivity; peptic ulcer disease; recent GI bleeding or perforation; renal insufficiency
Interactions	Coadministration with aspirin increases risk of inducing serious NSAID-related adverse effects; probenecid may increase concentrations and, possibly, toxicity of NSAIDs; may decrease effect of hydralazine, captopril, and beta-blockers; may decrease diuretic effects of furosemide and thiazides; may increase PT when taking anticoagulants (instruct patients to watch for signs of bleeding); may increase risk of MTX toxicity; phenytoin levels may be increased when administered concurrently
Pregnancy	B - Usually safe but benefits must outweigh the risks.
Precautions	Category D in third trimester of pregnancy; acute renal insufficiency, interstitial nephritis, hyperkalemia, hyponatremia, and renal papillary necrosis may occur; patients with preexisting renal disease or compromised renal perfusion risk acute renal failure; leukopenia occurs rarely, is transient, and usually returns to normal during therapy; persistent leukopenia, granulocytopenia, or thrombocytopenia warrants further evaluation and may require discontinuation of drug

Drug Name	Indomethacin (Indocin) -- Rapidly absorbed; metabolism occurs in liver by demethylation, deacetylation, and glucuronide conjugation. Inhibits prostaglandin synthesis.
Adult Dose	25-50 mg PO bid/tid 75 mg SR bid; not to exceed 200 mg/d
Pediatric Dose	1-2 mg/kg/d divided PO bid/qid; not to exceed 4 mg/kg/d or 150-200 mg/d
Contraindications	Documented hypersensitivity; GI bleeding or renal insufficiency.
Interactions	Coadministration with aspirin increases risk of inducing serious NSAID-related adverse effects; probenecid may increase concentrations and, possibly, toxicity of NSAIDs; may decrease effect of hydralazine, captopril, and beta-blockers; may decrease diuretic effects of furosemide and thiazides; may increase PT when taking anticoagulants (instruct patients to watch for signs of bleeding); may increase risk of MTX toxicity; phenytoin levels may be increased when administered concurrently
Pregnancy	B - Usually safe but benefits must outweigh the risks.
Precautions	Category D in third trimester of pregnancy; acute renal insufficiency, hyperkalemia, hyponatremia, interstitial nephritis, and renal papillary necrosis may occur; increases risk of acute renal failure in patients with preexisting renal disease or compromised renal perfusion; reversible leukopenia may occur (discontinue if persistent leukopenia, granulocytopenia, or thrombocytopenia develops)

Drug Name	Sulindac (Clinoril) -- Decreases activity of COX and, in turn, inhibits prostaglandin synthesis. Results in a decreased formation of inflammatory mediators.
Adult Dose	150-200 mg PO bid or 300-400 qd; not to exceed 400 mg/d
Pediatric Dose	Not established
Contraindications	Documented hypersensitivity; patients in whom aspirin, iodides, or other NSAIDs induce hypersensitivity; GI bleed and renal insufficiency
Interactions	Coadministration with aspirin increases risk of inducing serious NSAID-related adverse effects; probenecid may increase concentrations and, possibly, toxicity of NSAIDs; may decrease effect of hydralazine, captopril, and beta-blockers; may decrease diuretic effects of furosemide and thiazides; may increase PT when taking anticoagulants (instruct patients to watch for signs of bleeding); may increase risk of MTX toxicity; phenytoin levels may be increased when administered concurrently
Pregnancy	C - Safety for use during pregnancy has not been established.
Precautions	Category D in third trimester of pregnancy; acute renal insufficiency, hyperkalemia, hyponatremia, interstitial nephritis, and renal papillary necrosis may occur; increases risk of acute renal failure in preexisting renal disease or compromised renal perfusion; low WBC counts occur rarely and usually return to normal in ongoing therapy; discontinuation of therapy may be necessary if persistent leukopenia, granulocytopenia, or thrombocytopenia develops; caution in anticoagulation defects or patients receiving anticoagulant therapy

Drug Name	Celecoxib (Celebrex) -- For those at risk of GI toxicity with NSAIDs. Inhibits primarily COX-2. COX-2 is considered an inducible isoenzyme, induced during inflammatory stimuli. Inhibition of COX-1 may contribute to NSAID GI toxicity. At therapeutic concentrations, COX-1 isoenzyme is not inhibited; thus, GI toxicity may be decreased. Seek lowest dose for each patient.
Adult Dose	200 mg/d PO qd; alternatively, 100 mg PO bid
Pediatric Dose	Not established
Contraindications	Documented hypersensitivity
Interactions	Coadministration with fluconazole may cause increase in celecoxib plasma concentrations because of inhibition of celecoxib metabolism; coadministration with rifampin may decrease celecoxib plasma concentrations
Pregnancy	B - Usually safe but benefits must outweigh the risks.
Precautions	Category D in third trimester of pregnancy; may cause fluid retention and peripheral edema; caution in compromised cardiac function, hypertension, and conditions predisposing to fluid retention; caution in severe heart failure and hyponatremia because may deteriorate circulatory hemodynamics; NSAIDs may mask usual signs of infection; caution in the presence of existing controlled infections; evaluate therapy when symptoms or lab results suggest liver dysfunction

Drug Name	Meloxicam (Mobic) -- Decreases activity of COX, which, in turn, inhibits prostaglandin synthesis. These effects decrease formation of inflammatory mediators.
Adult Dose	7.5 mg PO qd; may increase to 15 mg PO qd
Pediatric Dose	Not established
Contraindications	Documented hypersensitivity; active GI bleeding
Interactions	Coadministration with aspirin increases risk of inducing serious NSAID-related adverse effects; probenecid may increase concentrations and, possibly, toxicity of NSAIDs; may decrease effect of hydralazine, captopril, and beta-blockers; may decrease diuretic effects of furosemide and thiazides; may increase PT when taking anticoagulants (instruct patients to watch for signs of bleeding); may increase risk of MTX toxicity; phenytoin levels may be increased when administered concurrently
Pregnancy	C - Safety for use during pregnancy has not been established.
Precautions	Category D in third trimester of pregnancy; acute renal insufficiency, hyperkalemia, hyponatremia, interstitial nephritis, and renal papillary necrosis may occur; increases risk of acute renal failure in patients with preexisting renal disease or compromised renal perfusion; reversible leukopenia may occur (discontinue if persistent leukopenia, granulocytopenia, or thrombocytopenia develops)

Drug Name	Valdecoxib (Bextra) -- Second-generation COX-2 inhibitor that offers a very rapid onset and prolonged efficacy. Inhibits primarily COX-2. COX-2 is considered an inducible isoenzyme, induced during pain and inflammatory stimuli. Inhibition of COX-1 may contribute to NSAID GI toxicity. At therapeutic concentrations, valdecoxib does not inhibit COX-1 isoenzyme, decreasing GI toxicity.
Adult Dose	10 mg PO qd
Pediatric Dose	Not established
Contraindications	Documented hypersensitivity
Interactions	Coadministration with fluconazole may cause increase in valdecoxib plasma concentrations; coadministration with rifampin may decrease valdecoxib plasma concentrations
Pregnancy	C - Safety for use during pregnancy has not been established.
Precautions	Category D in third trimester of pregnancy; abdominal pain, nausea, and diarrhea may occur; caution in compromised cardiac function, hypertension, and conditions predisposing to fluid retention; caution in severe heart failure and hyponatremia because may deteriorate circulatory hemodynamics; NSAIDs may mask usual signs of infection; caution in the presence of existing controlled infections; evaluate therapy when symptoms or lab results suggest liver dysfunction

Drug Category: Immunosuppressants -- Inhibit key factors in the immune system responsible for inflammatory responses.

Drug Name	Methotrexate (Rheumatrex) -- Antimetabolite that inhibits dihydrofolate reductase, thereby hindering DNA synthesis and cell reproduction. Adjust dose gradually to attain satisfactory response.
Adult Dose	2.5 mg/wk PO/IM initially; administer 3 doses over a 24-h period, then titrate to as high as 25 mg/wk depending on response
Pediatric Dose	Not established
Contraindications	Documented hypersensitivity; alcoholism; hepatic insufficiency; documented immunodeficiency syndromes; preexisting blood dyscrasias (eg, bone marrow hypoplasia, leukopenia, thrombocytopenia, significant anemia); renal insufficiency
Interactions	Oral aminoglycosides may decrease absorption and blood levels of concurrent oral MTX; charcoal lowers levels; coadministration with etretinate may increase hepatotoxicity; folic acid or its derivatives contained in some vitamins may decrease response; probenecid, NSAIDs, salicylates, procarbazine, and sulfonamides (including TMP-SMZ) can increase plasma levels; may decrease phenytoin plasma levels; may increase plasma levels of thiopurines
Pregnancy	D - Unsafe in pregnancy
Precautions	Monitor CBCs monthly and liver and renal function every 1-3 mo during therapy (monitor more frequently during initial dosing, dose adjustments, or when risk of elevated MTX levels, eg, dehydration); has toxic effects on hematologic, renal, GI, pulmonary, and neurologic systems; discontinue if significant drop in blood counts occur; fatal reactions reported when administered concurrently with NSAIDs

Drug Name	Cyclosporine (Sandimmune, Neoral) -- Cyclic polypeptide that suppresses some humoral immunity and, to a greater extent, cell-mediated immune reactions such as delayed hypersensitivity, allograft rejection, experimental allergic encephalomyelitis, and graft-versus-host disease for a variety of organs. Demonstrated to be helpful in a variety of skin disorders, especially psoriasis.
Adult Dose	2.5-5 mg/kg/d PO in divided doses
Pediatric Dose	Administer as in adults
Contraindications	Documented hypersensitivity; uncontrolled hypertension or malignancies; do not administer concomitantly with PUVA or UVB radiation in psoriasis because may increase risk of cancer
Interactions	Carbamazepine, phenytoin, isoniazid, rifampin, and phenobarbital may decrease concentrations; azithromycin, itraconazole, nicardipine, ketoconazole, fluconazole, erythromycin, verapamil, grapefruit juice, diltiazem, aminoglycosides, acyclovir, amphotericin B, and clarithromycin may increase toxicity; acute renal failure, rhabdomyolysis, myositis, and myalgias increase when taken concurrently with lovastatin
Pregnancy	C - Safety for use during pregnancy has not been established.
Precautions	Evaluate renal and liver functions often by measuring BUN, serum creatinine, serum bilirubin, and liver enzymes; may increase risk of infection and lymphoma; reserve IV use only for patients who cannot take PO

Drug Category: Biologic therapies -- Postulated mechanisms include free radical–mediated oxidative damage to DNA; decreased secretion of IL-6, IL-1-beta, IL-10, and TNF-alpha; reduced angiogenesis; induction of IFN-gamma; and IL-2 production by CD8 T cells.

Drug Name	Etanercept (Enbrel) -- Acts by binding and inhibiting TNF, the cytokine that contributes to inflammatory and immune responses.
Adult Dose	25 mg SC twice weekly
Pediatric Dose	0.4 mg/kg SC; maximum single dose 25 mg
Contraindications	Documented hypersensitivity, sepsis, and concurrent live vaccination; reactivation of tuberculosis; possible drug-induced lupus
Interactions	None reported
Pregnancy	C - Safety for use during pregnancy has not been established.
Precautions	Caution in impaired renal function and asthma; discontinue administration if a serious infection develops; adverse effects may include pain at injection site, localized erythema, rash, UTI symptomatology, GI upset, nausea, vomiting, rhinitis, and cough

Drug Category: 5-Aminosalicylic acid derivatives -- Inhibit inflammatory reactions and pain by decreasing activity of COX, which is responsible for prostaglandin synthesis.

Drug Name	Sulfasalazine (Azulfidine, EN-Tabs) -- Acts locally in colon to decrease the inflammatory response and systemically inhibits prostaglandin synthesis. Loading dose is not necessary.
Adult Dose	1 g PO tid/qid initially; titrate to 2-4 g/d in divided doses depending on response
Pediatric Dose	<2 years: Not established >2 years: 40-60 mg/kg/d PO in 3-6 divided doses; follow by maintenance dose of 20-30 mg/kg/d divided qid
Contraindications	Documented hypersensitivity to sulfa drugs or any component; GI or GU obstruction
Interactions	Decreases effects of iron, digoxin, and folic acid; conversely, increases effect of oral anticoagulants, oral hypoglycemic agents, and MTX
Pregnancy	B - Usually safe but benefits must outweigh the risks.
Precautions	Caution in patients with renal or hepatic impairment, blood dyscrasias, urinary obstruction, or G-6-PD deficiency

FOLLOW-UP

Further Outpatient Care:

• Heat and cold treatments: Heat and cold treatments can temporarily relieve pain and reduce joint swelling. Examples of treatments include soaking in a warm tub or placing a warm compress or cold pack on the painful joint.

Deterrence/Prevention:

• A number of medications cause an exacerbation of psoriasis; therefore, avoidance of these medications may help prevent or minimize flare-ups.

• Lithium and withdrawal from systemic corticosteroids are well known to cause flares of disease.

• Beta-blockers, antimalarials, and NSAIDs also have been implicated.

Complications:

• Until recently, psoriatic arthritis generally was believed to be a mild disease, with severe joint deformity and destruction (called arthritis mutilans) occurring in only approximately 5% of patients. This severe condition usually occurs in the small joints of the hands and feet. Some reports now suggest that arthritis mutilans may occur in as many as 16% of patients and that it may be as severe as rheumatoid arthritis.

• Atlantoaxial subluxation with attendant neurological complications can occur. Rarely, patients with psoriatic arthritis may develop aortic insufficiency.

Prognosis:

• Until recently, psoriatic arthritis generally had been considered a milder disease than rheumatoid arthritis. The following factors influence the degree of severity:

• Clinical subset (eg, arthritis mutilans, symmetric polyarthritis)

• Early age of onset

• Severity of skin involvement

• Female sex

• Family history of arthritis

• Presence of HLA-DR7

• New evidence suggests that psoriatic arthritis may be as disabling and destructive as rheumatoid arthritis when the appropriate comparisons are made; thus, treatment should be aggressive in those individuals with progressive joint disease.

Patient Education:

• Patients may visit the Web sites of the Arthritis Foundation or the National Psoriasis Foundation for more information on their disease.

• For excellent patient education resources, visit eMedicine's Psoriasis Center and Arthritis Center. Also, see eMedicine's patient education articles Psoriatic Arthritis, Psoriasis, and Nail Psoriasis.

Special Concerns:

• Children with juvenile psoriatic arthritis should be examined by an ophthalmologist annually to check for several forms of eye inflammation associated usually with various forms of juvenile arthritis.

Caption: Picture 1. Psoriatic arthritis. Severe fixed flexion deformity of the interphalangeal joint.

Picture Type: Photo

Caption: Picture 2. Psoriatic arthritis. Comparison between sites of involvements in both hands and feet in psoriatic arthritis and rheumatoid arthritis.

Picture Type: Image

Caption: Picture 3. Psoriatic arthritis involving the distal phalangeal joint.

Picture Type: X-RAY

Caption: Picture 4. Swelling and deformity of the metacarpophalangeal and distal interphalangeal joints in a patient with psoriatic arthritis.

Picture Type: Photo

Caption: Picture 5. Psoriatic arthritis involving the distal phalangeal joint.

Picture Type: Photo

Caption: Picture 6. Severe psoriatic arthritis involving the distal and proximal interphalangeal joints.

Picture Type: Photo

Caption: Picture 7. Asymmetric arthritis pattern of psoriatic arthritis (fixed flexion deformity).

Picture Type: Photo

Caption: Picture 8. Psoriatic arthritis. Arthritis mutilans, a typically psoriatic pattern of arthritis, which is associated with a characteristic "pencil-in-cup" radiographic appearance of digits.

Picture Type: Photo

Caption: Picture 9. Psoriatic arthritis involving the distal phalangeal joint.

Picture Type: Photo

Caption: Picture 10. Psoriatic arthritis. Arthritis mutilans (ie, "pencil-in-cup" deformities).

Picture Type: X-RAY

BIBLIOGRAPHY

• Andrews BS, Lowe NJ: Therapy of psoriatic arthritis. In: Practical Psoriasis Therapy. 2nd ed. St. Louis, Mo: Mosby-Year Book; 1993: 239-55.
• Bruce I, Gladman DD: Psoriatic Arthritis: Recognition and Management. BioDrugs 1998; 9: 271.
• Calzavara-Pinton PG, Franceschini F, Manera C, et al: Antiperinuclear factor in psoriatic arthropathy. J Am Acad Dermatol 1999 Jun; 40(6 Pt 1): 910-3.
• Cather JC, Abramovits W, Menter A: Cyclosporine and tacrolimus in dermatology. Dermatol Clin 2001 Jan; 19(1): 119-37, ix.
• Clegg DO, Reda DJ, Mejias E, et al: Comparison of sulfasalazine and placebo in the treatment of psoriatic arthritis. A Department of Veterans Affairs Cooperative Study. Arthritis Rheum 1996 Dec; 39(12): 2013-20.
• Cuellar ML, Silveira LH, Espinoza LR: Recent developments in psoriatic arthritis. Curr Opin Rheumatol 1994 Jul; 6(4): 378-84.
• Dougados M, Maetzel A, Mijiyawa M, Amor B: Evaluation of sulphasalazine in the treatment of spondyloarthropathies. Ann Rheum Dis 1992 Aug;51(8):955-8.
• Eastmond CJ: Psoriatic arthritis. Genetics and HLA antigens. Baillieres Clin Rheumatol 1994 May; 8(2): 263-76.
• Feldmann M, Brennan FM, Maini RN: Role of cytokines in rheumatoid arthritis. Annu Rev Immunol 1996; 14: 397-440.
• Gladman DD, Shuckett R, Russell ML, et al: Psoriatic arthritis (PSA)--an analysis of 220 patients. Q J Med 1987 Feb; 62(238): 127-41.
• Gladman DD, Anhorn KA, Schachter RK, Mervart H: HLA antigens in psoriatic arthritis. J Rheumatol 1986 Jun; 13(3): 586-92.
• Gladman DD, Farewell VT: Progression in psoriatic arthritis: role of time varying clinical indicators. J Rheumatol 1999 Nov; 26(11): 2409-13.
• Gonzalez S, Martinez-Borra J, Torre-Alonso JC, et al: The MICA-A9 triplet repeat polymorphism in the transmembrane region confers additional susceptibility to the development of psoriatic arthritis and is independent of the association of Cw*0602 in psoriasis. Arthritis Rheum 1999 May; 42(5): 1010-6.
• Goodfield M: Skin lesions in psoriasis. Baillieres Clin Rheumatol 1994 May;8(2):295-316.
• Griffiths CE: Therapy for psoriatic arthritis: sometimes a conflict for psoriasis. Br J Rheumatol 1997 Apr; 36(4): 409-10.
• Grundmann-Kollmann M, Mooser G, Schraeder P, et al: Treatment of chronic plaque-stage psoriasis and psoriatic arthritis with mycophenolate mofetil. J Am Acad Dermatol 2000 May; 42(5 Pt 1): 835-7.
• Gupta AK, Grober JS, Hamilton TA, et al: Sulfasalazine therapy for psoriatic arthritis: a double blind, placebo controlled trial. J Rheumatol 1995 May; 22(5): 894-8.
• Hohler T, Kruger A, Schneider PM, et al: A TNF-alpha promoter polymorphism is associated with juvenile onset psoriasis and psoriatic arthritis. J Invest Dermatol 1997 Oct; 109(4): 562-5.
• Kurschat P, Rubbert A, Poswig A, et al: Treatment of psoriatic arthritis with etanercept. J Am Acad Dermatol 2001 Jun; 44(6): 1052.
• Mader R, Gladman DD, Long J, et al: Does injectable gold retard radiologic evidence of joint damage in psoriatic arthritis? Clin Invest Med 1995 Apr; 18(2): 139-43.
• Mease PJ, Goffe BS, Metz J, et al: Etanercept in the treatment of psoriatic arthritis and psoriasis: a randomised trial. Lancet 2000 Jul 29; 356(9227): 385-90.
• Palit J, Hill J, Capell HA, et al: A multicentre double-blind comparison of auranofin, intramuscular gold thiomalate and placebo in patients with psoriatic arthritis. Br J Rheumatol 1990 Aug; 29(4): 280-3.
• Rahman P, Gladman DD, Cook RJ, et al: The use of sulfasalazine in psoriatic arthritis: a clinic experience. J Rheumatol 1998 Oct; 25(10): 1957-61.
• Roenigk HH, Maibach HI: Psoriatic arthritis. In: Psoriasis. 2nd ed. New York, NY: Marcel Dekkar; 1991: 171-87.
• Ruddy S, Harris ED Jr, Sledge CB, eds: Kelley's Textbook of Rheumatology. 6th ed. Philadelphia, Pa: WB Saunders; 2000.
• Sakkas LI, Marchesoni A, Kerr LA, et al: Immunoglobulin heavy chain gene polymorphisms in Italian patients with psoriasis and psoriatic arthritis. Br J Rheumatol 1991 Dec; 30(6): 449-50.
• Sontheimer RD, Provost TT, eds: Cutaneous Manifestations of Rheumatoid Diseases. 1st ed. Philadelphia, Pa: Lippincott Williams & Wilkins; 1996: 233-6.