Psoriatic Arthritis

History Taking

Chief Complaint:

• Joint pain and stiffness

• Skin lesions or rashes

History of Presenting Complaint:

• Joint pain typically asymmetric and often affecting the distal joints (such as the distal interphalangeal joints of the hand)

• Morning stiffness lasting more than an hour

• Descriptions of joint swelling or warmth

• Symptoms of enthesitis (pain at tendon and ligament insertion sites, such as the Achilles tendon)

• Fatigue

• Onset of skin lesions prior to joint symptoms in majority of cases

• Presence of nail changes such as pitting or onycholysis (separation of the nail from the nail bed)

System Review:

• Dermatological: presence of psoriasis, typically plaque-like, often on the extensor surfaces, scalp or natal cleft

• Musculoskeletal: joint pain, stiffness, swelling; axial involvement possible leading to lower back pain

• Eye: Uveitis or conjunctivitis

Past Medical History:

• History of psoriasis

• Co-morbid conditions like cardiovascular disease, diabetes, or depression which are often associated with psoriatic arthritis

Drug History:

• Use of nonsteroidal anti-inflammatory drugs (NSAIDs) for pain relief

• Medications for psoriasis, such as topical corticosteroids or systemic agents like methotrexate or biologics

• History of poor response to disease-modifying anti-rheumatic drugs (DMARDs)

Family History:

• Family members with psoriasis or psoriatic arthritis

• Other autoimmune diseases in the family

Personal History:

• Smoking: Increased risk for psoriatic arthritis in smokers

• Obesity: Increased risk in those with higher body mass index

Social History:

• Impact on work or daily activities due to joint pain, stiffness, or skin lesions

• Psychological distress or depression related to disease impact on quality of life

• Any physical activity limitations due to pain or stiffness

Physical Examination

General Examination:

• Psoriatic skin lesions: Erythematous plaques with silvery scales, most commonly on extensor surfaces and scalp

• Nail changes: Pitting, onycholysis, discoloration or thickening

Hands and Arms Examination:

• Asymmetrical joint swelling: suggestive of inflammatory arthritis

• Dactylitis (sausage fingers or toes due to inflammation): a distinctive feature of psoriatic arthritis

• Evidence of enthesitis: tenderness at insertion of tendons or ligaments

Mouth and Neck Examination:

• No specific findings usually associated with psoriatic arthritis

Cardiovascular Examination:

• No specific findings usually associated with psoriatic arthritis

Respiratory Examination:

• No specific findings usually associated with psoriatic arthritis

Abdomen Examination:

• No specific findings usually associated with psoriatic arthritis

Neurology Examination:

• No specific findings usually associated with psoriatic arthritis

Additional Examination if Required:

• Eye examination to look for signs of uveitis: redness, pain, blurred vision

• Lower back and sacroiliac joints examination for evidence of spondylitis or sacroiliitis: tenderness, reduced range of movement, pain on extension of the spine

• Lower limb examination for enthesitis, particularly at the Achilles tendon and plantar fascia

Investigations

Laboratory Tests:

• Full blood count: to check for evidence of inflammation or anemia associated with chronic disease

• C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR): markers of systemic inflammation, often raised in active psoriatic arthritis

• Rheumatoid factor (RF) and anti-cyclic citrullinated peptide (anti-CCP): usually negative in psoriatic arthritis, helps differentiate from rheumatoid arthritis

• HLA-B27: may be positive if axial disease is present

• Uric acid levels: to rule out gout, especially when there is asymmetric arthritis with involvement of distal interphalangeal (DIP) joints

Imaging:

• X-rays of affected joints: may show asymmetric joint space narrowing, erosions, new bone formation, "pencil-in-cup" deformity characteristic of psoriatic arthritis

• MRI of sacroiliac joints or spine: if symptoms of axial involvement to assess for spondylitis or sacroiliitis

• Ultrasound: may show joint inflammation, synovitis, enthesitis, dactylitis

Invasive:

• Joint aspiration: to rule out infectious arthritis or gout if an individual joint is significantly inflamed or if the diagnosis is uncertain

Other Tests:

• Skin biopsy: if skin lesions are present and the diagnosis of psoriasis is uncertain, a biopsy may be performed

• Dermatology review: if the skin condition is complex or uncertain

• Ophthalmology review: in the case of ocular symptoms to rule out uveitis or other eye involvement

Management

General Management:

• Patient education: about the nature of the disease and importance of regular follow-up

• Lifestyle modifications: regular exercise, maintain a healthy weight, smoking cessation

• Physiotherapy: to maintain joint function and mobility

Medical Management:

• Non-steroidal anti-inflammatory drugs (NSAIDs): for symptomatic relief of joint pain and stiffness

• Disease-modifying antirheumatic drugs (DMARDs): methotrexate, sulfasalazine or leflunomide, for control of inflammation and to prevent joint damage

• Biologic agents: Tumour necrosis factor (TNF) inhibitors (etanercept, infliximab, adalimumab), interleukin 12/23 inhibitor (ustekinumab), or interleukin 17 inhibitors (secukinumab, ixekizumab) when the response to DMARDs is inadequate or they are not tolerated

• Corticosteroids: short term use for severe inflammation, can be systemic or intra-articular injection

Surgical Management:

• Joint replacement surgery: for patients with severe joint damage causing functional impairment

• Synovectomy: may be considered for persistent joint inflammation

Other:

• Multidisciplinary approach: involving dermatologists, rheumatologists, physical therapists, and sometimes surgeons for comprehensive management

• Regular follow-up: to monitor disease activity, adjust treatment, and manage complications

• Psychological support: if needed, to address the emotional impact of living with a chronic condition like psoriatic arthritis