Psoriatic arthritis classification

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Chandrakala Yannam, MD [2]

Overview

According to the severity of the disease, psoriatic arthritis may be classified into mild, moderate, and severe form of arthritis.

Based on the severity, psoriatic arthritis may be classified into following categories:^[1]
- Mild
- Moderate
- Severe

Organ system involvement	Mild psoriatic arthritis	Moderate psoriatic arthritis	Severe psoriatic arthritis
Peripheral arthritis	<5 joints involvement No damage can be seen on x-ray No loss of physical function Minimal impact on patient’s quality of life	⩾5 joints involvement Damage can be visible on x-ray Non-responsive to NSAIDs Moderate impact on patient’s quality of life	⩾5 joints involvement Severe damage may be seen on x-ray Nonresponsive to NSAIDs, standard DMARDs Severe impact on patient’s quality of life
Axial joint involvement	Mild pain present No loss of physical function	Loss of physical function Bath Ankylosing Spondylitis Disability Activity Index (BASDAI) >4	Failure of response
Skin	Body Surface Area ( BSA) <5 Psoriasis area and severity index (PASI) <5	Resistant to topical therapy Dermatology Life Quality Index (DLQI)<10 PASI<10	BSA>10, DLQI>10PASI>10
Dactylitis	+/- Pain Normal activity/ function	Presence of erosive disease or loss of physical function	Failure of response to NSAIDs and conventional DMARDs
Enthesitis	Number of sites involved:1–2 No loss of physical function	Number of sites involved >2 or Loss of function	Loss of function >2 sites involvement and failure of response

↑ Ritchlin CT, Kavanaugh A, Gladman DD, Mease PJ, Helliwell P, Boehncke WH, de Vlam K, Fiorentino D, Fitzgerald O, Gottlieb AB, McHugh NJ, Nash P, Qureshi AA, Soriano ER, Taylor WJ (September 2009). “Treatment recommendations for psoriatic arthritis”. Ann. Rheum. Dis. 68 (9): 1387–94. doi:10.1136/ard.2008.094946. PMC 2719080. PMID 18952643.