Enthesitis of the hands in psoriatic arthritis: an ultrasonographic perspective

Abstract

Psoriatic arthritis is a systemic inflammatory disease in which enthesitis and dactylitis are two of the main hallmarks of the disease. In the last years, ultrasonography is increasingly playing a key role in the diagnosis of psoriatic arthritis and ultrasonography of the entheses, particularly of the lower limbs, is commonly used to assess patients with that disease. New advancements in ultrasound equipment using high frequencies probes allowed us also to identify and characterize the involvementof the entheses of the hand in psoriatic arthritis, confirming the results of the experimental models of the disease and the theory of the sinovial-entheseal complex, even in small joints.

Ultrasonography of the nail unit reveals quantitative and qualitative alterations in patients with psoriasis and psoriatic arthritis

“…A few previous studies of magnetic resonance imaging (MRI) also described the strong relationship between the distal interphalangeal joint (DIP) and the nail [14,26]. The US approach to the nail is also promising, with several chances of application in everyday practice [16,27]. The quantitative approach was explored by Wollina et al [28] with volumetric measurements of the nail and a qualitative description of the image, detailing the alterations which were not evident at clinical examination [19,29].…”

How Variable Is the Volar Subcutaneous Tissue of the Digits on B-Mode and Color Doppler Ultrasound in Non-Psoriatic Individuals and Could It Be Included in a Dactylitis Score?

“…In US-as-sessed dactylitis, SCT inflammation is visualized as the loss of normal B-mode pattern with heterogeneous hypoechoic areas, with or without a Doppler signal. These changes have been interpreted as edema or even as inflammatory involvement of functional entheses that link the flexor tendons to the skin such as the Cleland's or Grayson's ligament [16]. However, in addition to this, thickening of the finger flexor SCT and increased Doppler signal within this anatomic area has been shown as abnormal findings specific for PsA [15,17,20] as well as markers of finger inflammation [21,22].…”

Power Doppler Ultrasound Assessment of A1 Pulley. A New Target of Inflammation in Psoriatic Arthritis?

“…A possible link between A1 pulley thickening and dactylitis through a "deep Koebner" phenomenon was hypothesized because of the correlation between this finding and previous dactylitis (7). In a case report, inflammatory involvement of annular pulleys was depicted by US in a PsA patient (8), and power Doppler (PD) enhancement of annular pulleys was found in active psoriatic dactylitis (9). Moreover, in a very recent article, MRI signs of inflammatory involvement of annular pulleys were more often encountered in a small cohort of PsA patients compared to RA patients and healthy controls (10).…”