ABC of Pain: Edited by Jane C Ballantyne

Pain, as a sub modality of somatic sensation, has been defined as a complex constellation of unpleasant sensory, emotional and cognitive experiences provoked by real or perceived tissue damage and manifested by certain autonomic, psychological, and behavioral reactions. The benefit of these unpleasant sensations, however, is underscored by extreme cases: patients lacking the ability to perceive pain due to hereditary neuropathies often maintain unrealized infections; self mutilate, and have curtailed life spans. Normally, nociception and the perception of pain are evoked only at pressures and temperatures extreme enough to potentially injured tissues and by toxic molecules and inflammatory mediators. As opposed to the relatively more objective nature of other senses, pain is highly individual and subjective and the translation of nociception into pain perception can be curtailed by stress or exacerbated by anticipation (Woolf).