Nail disease

William Tillett, MD, PhD, on Psoriatic Nail Dystrophy and DIP Joint Disease

We know nail pitting is associated with an increased likelihood of developing psoriatic arthritis (PsA), but is psoriatic nail dystrophy a useful clinical marker for radiographic damage in the hands?

To explore this, William Tillett, MD, PhD, from the Department of Rheumatology at Royal National Hospital for Rheumatic Diseases in Bath, England, and colleagues used χ2 tests to determine the association between features of nail dystrophy and radiographic damage in the DIP joints of 134 patients with PsA.

Results showed the presence of any form of psoriatic nail dystrophy was associated with erosion at the DIP joints of the corresponding digit, which was primarily driven by the presence of nail onycholysis.

Rheumatology Consultant caught up with Dr Tillett about the research.

Rheumatology Consultant: What is the biggest challenge for rheumatologists in managing psoriatic nail dystrophy among patients with PsA?

William Tillett: I think recognizing psoriatic nail disease is the first hurdle for us as practicing rheumatologists. I spend much of my consulting time focused on articular, axial, entheseal, or skin disease, so nail disease is easy to forget. Yet nail disease remains a significant burden for our patients, both cosmetically and functionally. 

RHEUM CON: What prompted you to conduct the study?

WT: We know nail pitting is common among people living with psoriasis and is an independent risk factor of developing PsA. However, we do not know which nail manifestations are associated with more destructive disease. We wanted to evaluate the association of individual nail manifestations and structural damage at the DIP joint.

RHEUM CON: What is the key takeaway message of your study?

WT: The key message in practice here is that onycholysis and subungual hyperkeratosis are associated with structural damage and can be a clinical sign to rheumatologists to investigate for more severe disease. The findings also demonstrate the close anatomical, radiological, and clinical association between psoriatic nail dystrophy and articular disease.

RHEUM CON: What should a rheumatologist remember when treating a patient with PsA with nail dystrophy?

WT: I would encourage rheumatologists to use the Group for Research and Assessment of Psoriasis and Psoriatic Arthritis (GRAPPA) guideline, because it divides treatment options according to disease domain. The GRAPPA guideline is also in the process of being updated. When selecting a medication for a patient, I would encourage the rheumatologist to think about the skin and nails and select an agent that would be effective for these manifestations, as well as joint disease.

RHEUM CON: What are the next steps of your research?

WT: We will present data on the validity of the Severity of Nail Psoriasis Score (SNAPS), a test we use in routine clinical care, at the 2019 American College of Rheumatology Meeting. SNAPS is more feasible in routine care than the modified Nail Psoriasis Severity Index that is used in clinical trials. We will also present data from the Bath PsA database that examined the effect of biologic disease-modifying antirheumatic drugs on the nail in the real-world setting, at the 2020 Annual European Congress of Rheumatology.


Antony A, Allard A, Rambojun A, et al. Psoriatic nail dystrophy is associated with erosive disease in the distal interphalangeal joints in psoriatic arthritis: a retrospective cohort study. J Rheumatol. 2019;46(9):1097-1102. doi:10.3899/jrheum.180796.