Hypoalgesia or hypalgesia denotes a decreased sensitivity to painful stimuli.
Hypoalgesia occurs when nociceptive (painful) stimuli are interrupted or decreased somewhere along the path between the input (nociceptors), and the places where they are processed and recognized as pain in the conscious mind. Hypoalgesic effects can be mild, such as massaging a stubbed toe to make it hurt less or taking aspirin to decrease a headache, or they can be severe, like being under strong anesthesia. Hypoalgesia can be caused by exogenous chemicals such as opioids, as well as by chemicals produced by the body in phenomena such as fear- and exercise- induced hypoalgesia. Hypoalgesia can also be associated with diseases, such as CIPA or in less severe cases with diabetes or other diseases associated with hypertension.