This article is adapted from He Liangzhi, Department of Traditional Chinese Medicine, Xiyuan Hospital, China Academy of Chinese Medical Sciences.
Cold and heat are fundamental concepts in understanding the nature of pathogenic factors and the imbalance of Yin and Yang in the development of diseases. They categorize various syndromes into two main types: cold syndromes and heat syndromes, based on the cold or heat attributes of symptoms and signs. Regardless of whether the condition is caused by external pathogens or internal injuries, syndromes caused by Yang pathogens are classified as heat, while those caused by Yin pathogens are classified as cold. A condition characterized by excess Yang or deficiency of Yin is considered heat, while a condition characterized by excess Yin or deficiency of Yang is considered cold.
Yang pathogens can lead to excess Yang or deficiency of Yin, while Yin pathogens can easily lead to excess Yin or deficiency of Yang. Therefore, the understanding of pathogenic factors and the analysis of the body’s Yin and Yang are fundamentally unified. Below, we will introduce how Traditional Chinese Medicine distinguishes between cold and heat syndromes.
Symptoms associated with Yang pathogens, excess Yang, or deficiency of Yin typically manifest as fever, aversion to heat, red eyes, flushed face, and thirst for cold drinks, which are indicative of heat. In contrast, symptoms associated with Yin pathogens, excess Yin, or deficiency of Yang typically manifest as aversion to cold, fear of cold, pale complexion, and lack of thirst for hot drinks, which are indicative of cold. Thus, the understanding of the basic nature of pathogenic factors and the classification of symptoms and signs based on their cold or heat attributes are unified, forming the diagnostic framework of distinguishing between cold and heat syndromes.
Yin and Yang pathogens can both cause disease and can transform into one another. The imbalance of Yin and Yang in the body can also undergo transformation and overlap. Therefore, in clinical practice, there are many cases of mixed cold and heat syndromes and transformations between cold and heat. In some cases, a syndrome characterized by excess Yang may present with some cold signs, while a syndrome characterized by excess Yin may present with some heat signs. These are all illusions, referred to as true heat with false cold and true cold with false heat. The differentiation between cold and heat syndromes and the differentiation between exterior and interior syndromes can alternate and overlap, meaning that both exterior and interior syndromes can present as exterior cold or heat syndromes, or interior cold or heat syndromes.