The study compared CT-based muscle and fat composition in 61 patients with hidradenitis suppurativa (HS) and 59 age- and sex-matched controls. Myosteatosis was independently associated with HS (OR = 3.88, p = 0.004) and history of biological therapy (OR = 0.085). HS patients had significantly higher intermuscular adipose tissue (1574.8 ± 1243.8 cm² vs. 1112.7 ± 822.5 cm², p = 0.029) and low attenuation muscle area (LAMA) (5013.1 ± 1999.24 cm², p < 0.001), as well as higher LAMA/BMI indices and lower indices. NAMA/BMI (p < 0.001). The prevalence of sarcopenia was similar between groups. Hypertensives showed lower NAMA/TAMA indices and higher LAMA/BMI indices. HS severity was negatively correlated with HDL cholesterol (p < 0.001). BMI, total muscle area, subcutaneous and visceral adipose tissue were similar between groups. HS is thus associated with myosteatosis, not sarcopenia.