**5.2 Medium vessel vasculitis**

*Vascular Biology - Selection of Mechanisms and Clinical Applications*

In patients with Sjögren syndrome (SSj), NFC can be normal in up to 59% of cases, if RP is absent [19]. The more frequent findings in this disease are tortuosities, crossings, and ingurgitated venous plexus (**Figure 9**). In patients carrying positive anticentromere antibody, dilated loops and giant capillaries can also be found. No correlations were stated between NFC changes and laboratory parameters.

The different abnormalities found in rheumatoid arthritis patients confirm the coexistence of microangiopathy in this disease [37]. In patients without rheumatoid vasculitis, it is frequent to find thin, long, and tortuous capillaries, with ingurgitated anarchic venous plexus and microhemorrhages [19]. These changes have no correlation with disease activity. Dilated or giant capillaries are rare and justify a closer follow-up.

NFC in psoriasis usually reveals a reduced capillary density, with avascular areas, and morphologically abnormal capillaries [38]. No correlation was found between capillary density and disease duration or the extent of skin involvement, but avascular areas are more frequent in patients whose nails are also affected. If the exam is performed over the psoriasis plaques, dilated and long loops can be seen,

Vasculitides evolve by inflammation of vessels, which include capillaries. NFC can, then, provide valuable information on the approach of patients with vasculitis. Although scarce research has been made in this field, a recent systematic review, following Chapel-Hill nomenclature, puts in evidence that NFC is more useful in small than in large vessel vasculitides [39, 40]. However, as large vessel vasculitides also involve microcirculation, the presence of NFC changes in these disorders cannot be excluded. Besides, NFC can also give important information about organ

The microangiopathy in vasculitides reveals several and heterogeneous NFC changes, but generally nonspecific, when compared to scleroderma pattern. Increased tortuosity; microhemorrhages; enlarged, bushy, and bizarre capillaries; and architectonic disarrangement are the most frequent findings [39]. In some cases, however, the described NFC abnormalities include capillary dilation and reduced density, which are usually associated with scleroderma spectrum diseases. Whether a deep capillary damage is due to primary vasculitis or if there is a possible

A recent study revealed that in Takayasu arteritis (TA) capillaries are affected due to hypoperfusion [43]. NFC abnormalities found were reduced capillary length and venous limb diameter and tortuosity, but, in hands with subclavian involvement, these changes were more severe. Capillary diameter was then considered as an example of subclavian artery stenosis alteration due to disease progression. We found no data about nailfold capillaroscopy in giant cell arteritis.

overlap of cases with scleroderma-related disorders is yet to be clarified.

**4.5 Sjögren syndrome**

**4.6 Rheumatoid arthritis**

with interstitial edema and fast blood flow [19].

involvement and disease activity [41, 42].

**5.1 Large vessel vasculitis**

**5. Nailfold capillaroscopy in noninfectious vasculitides**

**4.7 Psoriasis**

**180**

In polyarteritis nodosa, NFC can be normal in the absence of Raynaud's phenomenon [19]. Yet, in its presence, changes include reduced capillary density, microhemorrhages, and edema. When digital ischemia is present, important edema, capillary flow sludge, and multiple hemorrhages can be seen (**Figure 13**).

Only one study about Kawasaki disease and NFC was found and it involved 64 pediatric patients [44]. Microcirculation abnormalities found included reduced density, dilation of arterial and venous limb diameters, higher intercapillary distance, and abnormal loops. The latter two were related to disease activity, as they improved from postacute to convalescent phase. Blood velocity was associated with increased coronary artery diameter.
