Serum C-reactive protein (CRP) levels are higher in Hidradenitis Suppurativa (HS) patients than in controls; significantly higher levels of serum CRP were even found in the patients with severe disease manifestations. The study showed CRP levels to be associated with the severity and stage of HS, therefore serum CRP level is a valuable parameter in patient evaluation and management. Here, CRP is linked to histiocytic sarcoma.