Ultrasound Assessment of Changes in Nails in Psoriasis and Psoriatic Arthritis

AIM OF THE STUDY: The aim of the study was to conduct an ultrasound (US) assessment of changes in fingernails in psoriatic patients with nail involvement. MATERIAL: A total of 69 patients with psoriatic changes in nails participated in the study, including 38 patients with psoriasis (Ps) and 31 with psoriatic arthritis (PsA) and 30 people in the control group. A total of 988 nails were examined. RESULTS: The thickness of the nail plate, nail bed, and matrix as shown in an ultrasound examination increased with the mNAPSI index (r=0.328, p=0.021; r=0.219, p=0.036; and r=0.422, p=0.011, respectively). The thickness of nail plate, bed, and matrix in patients with onycholysis and hyperkeratosis-type changes (concomitant or present separately) was significantly greater than when only pitting-type changes occurred (p=0.007, p=0.035, and p=0.023, respectively). An examination of nails with only pitting-type changes showed an increase in the matrix thickness compared to the control group (p=0.018). The focal hyperechoic involvement of the dorsal plate (80%) was the change most often observed in an US examination in Ps patients, whereas loosening of the borders of the ventral plate was most often observed in PsA patients. The thickness of nail bed in PsA patients increased with the duration of arthritis (r=0.399, p=0.022) and was correlated with the number of swollen digits (r=0.278, p=0.041). CONCLUSIONS: The findings of this study may indicate an association of an inflammation in the nail bed with PsA development. Apart from a direct assessment of the described morphological changes of nails, a US examination could prove useful in an assessment of intensity of a local inflammation as a prognostic factor for PsA development.