Background Systemic lupus erythematosus (SLE) patients often suffer hand function limitations even in the absence of symptoms related to joint or tendon disorders. Recent researches reported the presence of ultrasonographic (US) subclinical synovitis and tendon involvement in asymptomatic patients. We aimed to assess US patterns in SLE patients and determine their relationship with clinical assessment, disease activity and hand functional status using handheld dynamometry. Results We assessed 30 SLE patients (60 hands) using US; 21 (70%) patient had synovial hypertrophy, 8 (26%) showed a power Doppler (PD) activity, 6 (20%) had erosions and 11 (36.6%) had tendon US abnormality. Both patients with hand arthralgia/arthritis (symptomatic) and patients without arthralgia/arthritis (asymptomatic) had a statistically insignificant difference regarding the global synovitis score (p = 0.2) and disease activity (p = 0.3). However, the symptomatic group had a significantly increased number of joints with effusion (p = 0.04) and tendons involved (p = 0.04). The mean grip strength had a significant negative correlation with SLEDAI-2 K score (rs = − 0.4, p = 0.02) in the total patient group. In the asymptomatic group, a negative correlation was found between both mean grip (rs = − 0.5, p = 0.04) and pinch strength (rs = − 0.6, p = 0.01) with PD index, and mean pinch strength with the Jaccoud’s arthropathy index (rs = − 0.49, p = 0.05). Conclusions SLE patients may have higher subclinical synovitis, erosions and tendon involvement than expected, which may in turn reduce hand grip and pinch strength. Disease activity may also have a negative impact on the hand grip functional strength.