Joint problems in Patients with Psoriasis

Think of Psoriatric Arthritis ! (PsA) (differential diagnosis: osteoarthritis, gout, Crohn’s disease)

Caracteristics of Psoriasis Arthritis
-affects individuals between 30 and 50 years old. It is due to overexpression of TNFalpha in the joints.
–skin lesions of Psoriasis (P) appear 5 to 10 years before PsA in in 70% of patients. That means that the dermatologist will be at the forefront to detect PsA.
-PsA preceeds P by 10 15 years 10% of the time
–P is accompanied by PsA 10-15% of the time (In Europe the association seems to occur less than 5%)
-All in all quality of life is severely impaired

What are the clinical features of Psoriatric Arthritis ?
–asymmetrical oligoarthritis :

• present in 14-70% of PsA- predominantly in females
• usually affects the knee, elbow or shoulder. It can be difficult to detect when symmetrical

–DIP joint arthritis (Distal Interphalyngeal Joint)

• present in 1-16% of patients with PsA
• More specific of PsA than the other inflammatory arthritis

–Dactylitis:

• painful swelling
• also called sausage digit: on fingers. But it can occur on the toes (so don’t forget to ask the patient to take the shoes off !)

–Enthesitis

• inflammation of the tendon or ligament which attaches to the joint capsule/bone
• often affects the patella and achilles tendon (again take the shoes off !)

-Arhtritis Mutilans: the end result of PsA where the joints are destroyed irreversibly….it occurs in 5% of patients with PsA

-…in addition to the joints, there is often muscle pain (Myalgia) which is often mistaken for fibromyalgia

Feature of PsA on imaging (Radiography): “pencil cup” deformity

How about the Nail changes in Plaque Psoriasis: are they helpful in identifying PsA ?

Nail characteristics in psoriasis (pitting, onycholysis, subungual hyperkeratosis…):
The association between nail involvement and PsA is not statistically significant

Psoriatic arthritis for the dermatologist. Alan Menter (United States). SY31 – Clinical Aspects of Psoriasis, Including Co-Morbidities. World Congress of Dermatology 2015 –  Vancouver, Canada