What causes the occipital lymph nodes to swell?

Lymph nodes: Occipital lymph nodes commonly swell with viral processes.

Varies: Solo or several enlarged nodes are usually reflective of a local process. Irritation of the scalp, a local bug bite, etc.Nodes are usually pea sized ; run a 3-4 week cycle of enlarging when stimulated, processing their irritant and returning to resting size. If continuing to enlarge, painful or persisting in an enlarged size after 3-4 wks, they need eval.

Occipital adenopathy: Swelling of occipital lymph nodes may occur from inflammation/infection of areas of the scalp. Diffuse enlargement of lymph nodes are seen with infectious mononucleosis, certain malignancies or bone marrow disorders.