Hyperpathia is an unpleasant sensation, often a burning pain, associated with elevated threshold for cutaneous sensory stimuli, such as light touch or hot and cold stimuli, especially repetitive stimuli. Even light stimuli may produce pain. Clinical features of hyperpathia may include summation (pain perception increases with repeated stimulation) and aftersensations (pain continues after stimulation has ceased).
The term thus overlaps to some extent with hyperalgesia (although the initial stimulus need not be painful itself) and dysesthesia. There is an accompanying diminution of sensibility due to raising of the sensory threshold (cf. allodynia), and the pain is not stimulus-bound (i.e., spreads beyond the area of stimulation).
Hyperpathia is a feature of thalamic lesions, and hence tends to involve the whole of one side of the body following a unilateral lesion, such as a cerebral hemorrhage or thrombosis. Generalized hyperpathia may also be seen in variant Creutzfeldt-Jakob disease, in which posterior thalamic (pulvinar) lesions are said to be a characteristic neuroradiological finding.