Diagnostic tools

What's used to monitor psoriasis and psoriatic arthritis?

When you develop a condition such as psoriasis or psoriatic arthritis, you may wonder once the diagnosis is made, how severity is assessed and how effectiveness of treatments (efficacy) are measured. This is particularly important when deciding to change a treatment.

There are a number of ways your healthcare provider (HCP) will assess your psoriasis and psoriatic arthritis and may include the following:

Measuring psoriasis

• Psoriasis Area, and Severity Index (PASI)
• Body Surface Area (BSA)
• Dermatology Quality of Life Index (DLQI)
• Physician’s Global Assessment (PGA)
• Lattice System Physician’s Global Assessment (LS-PGA)
• Self-Administered PASI (SAPASI)
• Salford Psoriasis Index (SPI)
• The static Physician Global Assessment (sPGA)
• Psoriasis Symptom Inventory (PSI)
• The Children's Dermatology Life Quality Index (CDLQI)
• Psoriasis Epidemiology Screening Tool (PEST)
• Static Physician's Global Assessment of Genitalia (sPGA-G)

Measuring psoriatic arthritis

• Disease activity in PsA (DAPSA)
• The Leeds Enthesitis Index (LEI)
• The Leeds Dactylitis Instrument (LDI)
• The dactylometer
• The Bath AS Disease Activity Index (BASDAI)
• AS Disease Activity Score (ASDAS)
• The minimal disease activity (MDA)
• The Composite Psoriatic Disease Activity Index (CPDAI)
• The PsA Disease Activity Score (PASDAS)
• Patient-Reported Outcome Measures (PROMs)
• Disease Activity Score (DAS28)
• The Psoriatic Arthritis Impact of Disease (PsAID12 and PsAID9)
• The Work Productivity and Activity Impairment (WPAI) questionnaire
• The Treatment Satisfaction Questionnaire for Medication (TSQM)

Some of these measurement tools, may only be used in specialist settings or for research trials.

Most are used to assess severity and to see if a treatment has improved the condition and symptoms. 

Source references:

• International Psoriasis Council: Psoriasis Measurement Tools [accessed 1 October 2020]
• Tucker LJ, Coates LC, Helliwell PS. Assessing Disease Activity in Psoriatic Arthritis: A Literature Review. Rheumatology and therapy, 2019 6(1), 23–32.