Systemic (Rheumatic)
Psoriatic Arthritis
건선성 관절염
Spondyloarthropathy associated with psoriasis; DIP, enthesitis, and dactylitis characteristic
- How common
- 20–30% of psoriasis patients
- Typical age
- Ages 30–50
What is it?
Same immune pathway as psoriasis (IL-17/IL-23/TNF) targets joints, entheses, spine, and nails.
Commonly affected: DIP joints, entheses, whole digits (dactylitis), sacroiliac joints
How it develops
- Genetic PredispositionHLA-B27 and PSORS gene associations
- IL-23/IL-17 AxisTh17-mediated inflammation
- Enthesitis + SynovitisInflammation at tendon/ligament insertions and joints
- Erosion + New BoneCharacteristic pencil-in-cup and fluffy periostitis
Symptoms
- DIP arthritisDIP swelling and pain (distinguishes from RA)
- Dactylitis (sausage digit)Entire digit swollen like sausage
- EnthesitisAchilles/plantar fascia insertion pain
- Axial involvementSacroiliitis/spondylitis (inflammatory back pain)
- Nail changesPitting, oil-drop sign, onycholysis
How it is examined
- Skin/scalp psoriasisSilvery scaly plaques (scalp, elbows, knees, umbilicus)
- Nail pitting/onycholysisPart of CASPAR criteria
- DactylitisUniform swelling of entire digit
- Achilles/plantar fascia tendernessEvidence of enthesitis
Imaging
Hand/foot X-ray shows 'pencil-in-cup' deformity, DIP involvement, fluffy periostitis, mutilans; sacroiliitis possible.
- Pencil-in-cup deformity
- DIP erosions + new bone
- Fluffy periostitis
- Arthritis mutilans (severe)
- Asymmetric sacroiliitis
MRI detects early enthesitis, synovitis, and bone marrow edema.
- Enthesitis with bone marrow edema
- Tenosynovitis/peritendinitis
- Synovitis
- Sacroiliac edema
Non-surgical care
- NSAIDsFirst-line for mild peripheral/axial symptoms
- Conventional DMARDsMethotrexate, sulfasalazine, leflunomide (peripheral arthritis)
- BiologicsTNF inhibitors, IL-17 inhibitors (secukinumab), IL-23 inhibitors (guselkumab)
- JAK inhibitors / apremilastTofacitinib, upadacitinib, apremilast (oral options)
Conservative options are generally tried first. Medications listed here can have side effects — discuss them with your prescriber.
When surgery is considered
Severe joint destruction, functional loss, arthritis mutilans
Procedures that may be discussed
- Synovectomy
- Joint replacement
- Finger arthrodesis
Outlook
Early biologic therapy can achieve remission; 5% progress to arthritis mutilans.