Nail Involvement as a Predictor of Psoriatic Arthritis
A recent study in the British Journal of Dermatology demonstrates that psoriatic involvement of the nail unit can be used as a predictor of psoriatic arthritis and can aid in early intervention to prevent the associated joint destruction. Psoriatic arthritis has been associated with diminished quality of life and reduced functional capacity for patients as compared to patients with plaque psoriasis.
In order to assess clinical and patient reported factors that could be used as predictors for psoriatic arthritis the researchers analyzed three independent studies done on patients in German dermatologic clinics in 2005, 2006, and 2008 on psoriasis and psoriatic arthritis health care. Outcomes from the study demonstrated that the strongest predictors of psoriatic arthropathy included both nail involvement and inpatient hospital treatment for psoriasis within the previous 5 years.
The connection of the fascia of the enthesis, connective tissue between the tendon or ligament and bone, is continuous with the root of the nail helping to explain the predictive value of nail changes with psoriatic arthritis. Furthermore, histology and high resolution MRI demonstrate that the extensor tendon overlying the distal interphalangeal joint is connected via tendinous fibers to both the nail root and nail matrix.
Limitations of this study include that the findings cannot be generalized to patients who are not under dermatologic treatment. In addition, the need to look for specific physical findings of nail psoriasis and their linkage to psoriatic arthropathy were not considered by the study.
By: A. Matthew Brunner MHS, PA-C, SDPA Diplomate & President-Elect
Image Credit: [Toshiyuki IMAI]