Inflammation of the periosteum. The condition is generally chronic, and is marked by tenderness and swelling of the bone and an aching pain. Acute periostitis is due to infection, is characterized by diffuse suppuration, severe pain, and constitutional symptoms, and usually results in necrosis. (Dorland, 27th ed). The disease is periostitis (MONDO_0004934, a Monarch Disease Ontology entry). Also known as: periosteum inflammation, periostitis (disease).