Pain due to a stimulus that does not normally provoke pain.
Allodynia is defined in terms of the response to clinical stimuli. It involves a change in the quality of a sensation, whether tactile, thermal, or of any other sort. Thusly, there is a loss of specificity of a sensory modality.
Allodynia is taken to apply to conditions that may give rise to sensitization of the skin, e.g., sunburn, inflammation, or trauma.