What condition involves inflammation of a gland or lymph node?

Adenitis is the medical term that specifically refers to the inflammation of a gland or lymph node. This condition can occur as a response to infection, inflammation, or other pathological processes, where the affected gland or node becomes swollen and painful. It is often associated with infections that could be localized or systemic, where the body's immune response triggers inflammation as a protective mechanism.

The other conditions listed do not pertain to the inflammation of glands or lymph nodes. Arthritis involves inflammation of the joints, nephritis refers to inflammation of the kidneys, and hepatitis denotes inflammation of the liver. Each of these conditions affects different bodily systems and structures, distinguishing them from adenitis.