Background The term undifferentiated connective tissue disease (UCTD) is used to describe a group of patients that lack definitive characteristics of any specific, well-defined connective tissue disease. The microcirculation may be affected and nailfold capillary abnormalities were sometimes described.

Objectives The aim of the study was to evaluate and depict the capillaroscopic features in these patients, especially in combination with Raynaud's phenomenon (RP).

Methods A consecutive cohort of 78 patients with UCTD and disease duration of at least one year was included in the study. Diagnosis of RP was based on a detailed history and/or observation of bilateral, cold-induced blanching and/or cyanosis of the fingers. Nailfold videcapillaroscopy (NVC) was performed blinded to disease group by the same investigator using a computerized videomicroscope at 200x magnification. The capillaroscopic findings were classified as normal, non-specific (tortuous, crossed, bizarre capillaries, haemorrhages, thrombotic capillaries), scleroderma pattern (SP) findings (definitely enlarged capillaries, giant loops/megacapillaries, bushy capillaries and angiogenesis, no, moderate or extensive loss of capillaries, architectural disruption of the nailfold capillary bed). Different data of continuous variables were described and compared using the Mann-Whitney U test. Comparison of categorical variables was performed using the χ² test with continuity correction. Statistical significance was defined as p<0.05.

Results The 78 patients consisted of 87% women (68/78) and we diagnosed RP in 41 (52.5%). The mean age was 45.1±14.7 (yrs±SD) and the mean disease duration 48.6±50.0 (months±SD). NVC abnormalities were present in 18/41 (43.9%) patients with UCTD+RP and in 1/37 (2.7%) without RP (p<0.0001). A considerable percentage of patients with RP (15%) had a normal NVC, compared to patients without RP (36.6%) (p=0.0004). Homogeneously enlarged loops were identified in 30/41 (73.1%) of UCTD+RP, in a higher percentage respect to patients without RP (27.0%) (p=0.0001). Irregularly enlarged loops and megacapillaries were found in 55% and 35% of UCTD+RP patients, respectively, in a significant high frequency respect to patients without RP. Bushy or angiogenetic capillaries and/or avascular areas were not found in both group. The combination of features suggestive for a SP without reduction in capillary density were present in 18/41 patients with UCTD+RP, and in 1/37 without RP (p=0.0003).

Conclusions In our UCTD+RP patients, irregularly enlarged and giant loops were predominant. We found neither moderate capillary loss, nor avascular areas in any of our patients. Only the SP without capillary loss distinguishes patients with RP from those without. This fact would also be supported by other results, which failed to show any of the findings typical of a severe or “active' disease involving nailfold microcirculation, such as features suggesting capillary re-growth (“bushy” capillaries), and “destruction” of capillaries (capillary loss/avascular areas) The typology of microvascular damage found in our patients is consistent with the general profile of UCTD, commonly considered as a condition characterised by a mild clinical picture.

1. De Angelis R, et al. Raynaud's phenomenon: clinical spectrum of 118 patients. Clin Rheumatol 2003; 22:279–84.

Disclosure of Interest None declared