A comparative observational study of nailfold capillaroscopy in psoriatic patients and healthy controls using a USB videodermatoscope

Psoriasis is a chronic, inflammatory disease which leads to microvascular changes. These changes can be assessed by nailfold capillaroscopy (NFC), a non-invasive, imaging technique used for real-time evaluation of the microcirculation of proximal nailfold capillaries.1 This comparative, observational study was conducted in a tertiary care hospital in New Delhi, India from March 2021 to April 2022. 75 psoriasis patients and 75 controls (age and sex-matched healthy volunteers) were recruited. Psoriasis was diagnosed clinically. NFC was done at ambient room temperature using the fourth and fifth digits of both hands. Using the polarizing mode of the USB videodermatoscope, images of the distal row of nailfold capillaries were taken in jpg format (Figures 1 and 2). The images were stored on the hard drive and interpreted by two independent blinded observers2 (p-value less than 0.05 was considered to be statistically significant). In our study, the majority of cases were in the 3rd and 4th decade of age. The nailfold capillary changes density in the psoriatic group was 6.40 ± 0.57 per mm while in the control group, it was 7.26 ± 0.41 per mm. Patients with psoriasis had significantly more capillary qualitative parameters [dilated (p < 0.001), giant (p < 0.001), bushy (p < 0.001), bizarre (p < 0.001), crisscross (p = 0.002), budding (p < 0.001), meandering capillaries (p < 0.001), microhemorrhages (p < 0.001), dropouts (p < 0.001), avascular areas (p < 0.001) and subpapillary venous plexus (p = 0.001) except tortuous capillaries (p = 0.397)] than healthy controls (Table 1). Bushy capillaries were present in 25 (33.3%) of psoriatic patients. Sivasanskari et al. also found ramified capillaries in psoriatic patients. Bushy and ramified capillaries both represent neovascularisation and reflect the manifestation of extensive inflammation.1 Dropout capillaries were present in 48 (64.0%) psoriatic patients and 11 (14.7%) controls. Ribeiro et al.2 also found more capillary deletion in psoriatic patients as compared to healthy controls. Avascular areas were present in 40.0% of psoriatic patients while a study done by Santhosh et al.3 found 55% of cases had avascular area. Budding capillaries were seen in 16.0% of psoriatic patients and none of the controls had budding capillaries. Budding capillaries, an early stage of bushy capillaries suggest neoangiogenesis.4 Patients with budding capillaries had lower body surface area, PASI score and disease duration. This denotes that budding capillary is the early marker of systemic inflammation in psoriatic patients. Budding capillaries along with dropouts and avascular areas are markers for tissue hypoxia and local production of vessel growth factors.2 NFC aids in the detection of these nailfold capillary abnormalities. Various studies observed that psoriatic patients had a strong association with cerebrocardiovascular diseases (especially stroke and myocardial infarction), osteoporosis, non-alcoholic fatty liver disease, end-stage renal disease and COPD.5 These complications occur secondary to ongoing systemic inflammation in psoriasis. NFC might help us in the early identification of psoriatic patients who are at risk of developing complications. We also suggest that with early initiation of systemic therapy, the aforementioned complication can be prevented. Further prospective studies are required to confirm this hypothesis. Psoriatic arthritis was found in one-quarter of psoriatic patients. Nail involvement was significantly higher among psoriatic arthritis patients (Table 2). Patients with psoriatic arthritis (PsA) had significantly more capillary dropouts and avascular areas than patients without PsA (Table 2). Capillary dropouts were significantly associated with disease duration. Rest all other parameters had no significant association in terms of gender, disease duration, BSA and PASI score. A study conducted by Fukasawa et al.6 found that NFC abnormalities were a predictor of PsA development and also correlated with the severity of PsA. We suggest that Nail changes along with nailfold capillary changes might help us to predict the likelihood of the development of PsA in psoriatic patients. Cross-sectional study design with a small sample size was the major limitation of our study. None. This study was approved by Institution ethics committee (Maulana Azad Medical College and Associated Hospital).