was long believed that skin, joint, and nail manifestations shared a common
cause. But recent studies suggest these to be traits of distinct disease conditions. The
severity and progression of skin, joint, and nail symptoms are frequently
For example joint disease in most patients develops up to 10
years after the initial skin presentation.
Though psoriasis and
psoriatic arthritis are co-morbid conditions, the genetic mechanisms
responsible for the course may be different. Even the basic physiology
governing both is supposed to differ. For example, selected key immune mediators of
disease in the skin and joints differ.
This explains why skin and joint symptoms
frequently do not respond equally or in parallel to treatment. It is therefore
best advised that the severity of skin, nails, and joints be assessed
separately. Recent studies published in PLoS ONE, an open access journal were
supportive of this concept.
a single measurement tool that has the ability to measure the presence and
severity of all clinical aspects of psoriasis does not exist.
A more robust analysis would hence be
necessary to better investigate the skin-joint relationship.
The study results provide evidence
against an association between the severity of joint and skin involvement in
patients with psoriasis and psoriatic arthritis, with the possible exception of
: Clinical Symptoms of Skin, Nails, and Joints Manifest Independently in
Patients with Concomitant Psoriasis and Psoriatic Arthritis; Knut et al; PloS