Psoriatic Arthritis (Psoriasis Arthritis) ICD-10: L40,5, M07
Contents
Definition
Psoriatic arthritis is rheumatoid arthritis (Arthritis) with joint and back disease affecting 5-10% of those with psoriasis in the skin
- Most often is psoriasis in the skin first present
- Psoriatic arthritis is a rheumatic inflammation that is classified among spondyloarthritis, but not counted among connective tissue diseases or vasculitides
- By suspected refer to rheumatologist for further consideration
Symptoms
- Psoriasis in the skin or scalp
- Nail abnormalities
- Joint stiffness
- Arthritis (Arthritis)
- Pain
- Reduced joint mobility
- Unstable joints
- May cause eye complications
Various types of psoriatic arthritis
Small joints are attacked
- Fingers, especially outer joints (DIP), thumb's outer joints (IP) and middle joints (PIP). Nail psoriasis coexist with external joint affection
Asymmetrical arthritis
- Several joints swell, most large joints such as one knee, one ankle, one elbow
Symmetrical arthritis
- Small and large joints swell at about the same time on the right and left side of the body (symmetrical)
- Similar Rheumatoid arthritis (arthritis), but not a rash in the blood
Mutilans
- Rare (5%), but destroys joints in fingers and feet
Spondylitis
- Looks like Bekhterevs (ankylosing spondylitis), but the tissue type (blood test) HLA-B27 occurs only in approx. 50% (more than 95% have HLA-B27 at Bekhterevs, approx. 8-15% in the general population)

Illustration: “Psoriasis on back” by English Wikipedia / James Heilman, wikimedia.org / CC BY 2.0
Classification criteria
(CASPAR = Classification Criteria for Psoriatic Arthritis, Reference: Helliwell PS, 2005)
At least three of the following five points:
- Proven psoriasis (one of A, B, C)
- Current psoriasis
- Disease history of psoriasis
- Family history of psoriasis among first- or second-degree relatives
- Psoriasis nails dystrophy (including onycholysis, pitting and hyperkeratosis observed by a doctor)
- Negative test for RF (rheumatoid factors)
- Dactylitis (one of A or B)
- Ongoing symptoms
- Disease history (documented by rheumatologist)
- Radiologically proven juxta-articular (near joint) new bone formation (not osteophytes)
Treatment
The treatment for PsA must be person-adapted largely because the disease varies greatly from person to person. Before starting treatment, it is important to be informed about the disease, what the goal of treatment is, and about side effects that may occur. The goal of treatment is to stop the disease completely, ie achieve remission, but also to reduce pain, improve quality of life, physical and social function. Unfortunately, there is no treatment that cures the disease.
- Treatment of symptoms with Ibux, other NSAIDs or mild pain-relieving drugs
- Joint fluid drainage and cortisone injections in large swollen joints
- Methotrexate
- Biological treatment
- Apremilast (Otezla)
- More about treatment EULAR guidelines, references: Smolen JS, 2018; EULAR: Gossec L, 2020 (medicines)
- Other literature on treatment here: reference: Kang EJ, 2015)
Treatment guidelines
EULAR: Gossec L, 2020 (medicines)
GRAPPA / EULAR 2017, Coates LC, 2017
Norwegian Rheumatological Association / The Norwegian Medical Association