Allergy is an exaggerated immune reaction to a usually harmless substance like pollen. Uncontrolled inflammatory and other allergic responses damage cells.
Anatomical information about cancer, abnormal cell growth and division caused by genetics and carcinogens, and cancer tumour classification or staging.
Cluster headaches produce severe pain on one side of the head. Sufferers typically experience a cluster of headaches followed by a period of no headaches.
Hypersensitivity reaction type IV is an allergic reaction (e.g. contact dermatitis) that occurs due to overactivity of immune cells called T lymphocytes.