As an external influence (normally termed [External Fire]), it is appears suddenly, being experienced as excessive body heat, dislike of heat and a preference for cold. It may be accompanied by high fever, rapid pulse, red face, red eyes, and dark reddish urine. Such febrile illnesses were often life threatening. Symptoms include boils, carbuncles and other reddish skin lesions. [Fire Poison] is the collection of [Heat] in parts of the body (called inflammation in Western medicine). Its symptoms are carbuncles, boils and red, swollen, raised and painful skin lesions. Fire pernicious influence can also produces symptoms associated with overheating and dehydration, such as thick mucous, scanty urine, burning sensations, thirst, constipation, agitation, etc. Because [Fire] induces reckless movement, particularly of [Blood] and [Shen], [Excess Fire] may produce haemorrhage or skin eruptions (in the case of [Blood]) or confused speech or delirium associated with fever (in the case of [Shen]).
As an internal influence (normally termed [Heat]), the signs are less severe and indicate a Deficiency of [Yin].