Skin flushing can be described as the experience of a sudden reddening of the skin which is usually accompanied by feelings of rushing blood and warm skin. In terms of its appearance, it manifests itself in an identical although more intense fashion to that which occurs across the face when one is embarrassed. Blotchiness or solid patches of redness are also often visible during states of skin flushing.
Skin flushing is most commonly induced under the influence of heavy dosages of opioid compounds, such as heroin, tramadol, fentanyl, and kratom. However, it can also occur under the influence of alcohol, certain psychedelics such as 5-MeO-DMT, and stimulants, such as caffeine.