Psoriatic Arthritis (Table 3-3) - Up to 30% of patients with psoriasis have arthritis; associated with moderate to severe psoriasis and typically occurs several years after appearance of skin lesions
- Rheumatoid factor negative (seronegative) arthritis; HLA-B27 association
- Tendons and ligaments often involved (enthesopathy or enthesitis) in addition to bone and cartilage
- ↑ TNFα level in synovium and serum in patients with psoriasis and psoriatic arthritis
- Almost all patients with psoriatic arthritis have nail changes (up to 20% may have no skin findings)
- Common features include pain at tendon insertion sites, digital involvement and sacroiliac disease, asymmetric joint involvement, negative rheumatoid factor, morning stiffness lasting more than 1 hour
- Treatment: TNFα antagonists, methotrexate, NSAID, cyclosporine, sulfasalazine
| | | | | | | Table 3-3 Forms of Psoriatic Arthritis | | | Type of Arthritis | | % | | Salient Features | | | Asymmetric oligoarthritis | | 70% | | Single or multiple distal joints in hands or feet involved; synovitis and joint swelling, ± swelling of digit (dactylitis or ‘sausage finger’); knees, ankles and sometimes axial involvement (if HLA-B27 positive) may also occur | | | Asymmetrical DIP arthritis | | 5–10% | | Single or multiple DIP joint involvement; periarticular swelling with concomitant nail involvement | | | Symmetrical polyarthritis
(RA-like) | | 15% | | Involvement of small and medium-sized joints (PIP, MCP, wrists, elbows); difficult to distinguish from rheumatoid arthritis (RA); usually seronegative | | | Spondylitis and sacroiliitis | | 5% | | Typically in men and resembles ankylosing spondylitis, with addition of knee and sacroiliac involvement, ± peripheral joint involvement, ± inflammatory bowel disease or uveitis, often positive for HLA-B27 | | | Arthritis mutilans | | 5% | | Digits become shorter, wider, softer due to osteolysis of phalanges and metacarpals; results in telescoping motion of digits | | | | | | | | | | | | | | | | | | | | | | X-ray findings: ‘pencil in cup’ deformity (distal head of bone appearing sharpened like a point), fusiform tissue swelling (‘sausage digit’), tuft resorption, eccentric erosions | | | | | | | | |
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