Myositis‐specific antibodies (MSAs) facilitate grouping children with juvenile dermatomyositis (DM) into distinct phenotypes. The first aim of this study was to investigate the link between anti‐p155/140 and lipodystrophy as determined by dual x‐ray absorptiometry (DXA) assessment of fat distribution. The second aim was to examine the relationship between anti‐p155/140 and damage to the nailfold capillary system. Children with juvenile DM followed for a minimum of 5 years were included. The study population was divided into 3 groups (anti‐p155/140, other MSA, and MSA negative). Lipodystrophy was assessed by physician assessment and DXA fat distribution (trunk‐to‐leg fat ratio). Documentation of nailfold capillary end row loops (ERLs) was obtained at diagnosis. A total of 96 subjects (44% anti‐p155/140, 23% other MSA, 33% MSA negative) were included. There was no significant difference in age, disease activity scores, or lipodystrophy between the 3 groups. The trunk‐to‐leg fat ratios were similar among the 3 groups at different time points. However, the anti‐p155/140 group had significantly decreased ERL counts (P= 0.006) at baseline as well as a prolonged duration of untreated disease at diagnosis (P= 0.027). Also, the anti‐p155/140 group had fewer patients with a monophasic disease course than the other 2 groups (P= 0.008). Generalized lipodystrophy frequency was equivalent in all 3 groups based on physician assessments and trunk‐to‐leg fat ratios. The anti‐p155/140 group had a greater loss of ERLs, suggesting that this MSA may impact the vascular component of juvenile DM.