Comprehensive Guide to Cold and Heat Inquiry in Traditional Chinese Medicine

What is meant by inquiring about cold and heat? It refers to asking the patient whether they feel cold or hot, emphasizing the patient’s sensations. The inquiry mainly focuses on the symptoms and feelings that the patient perceives. Therefore, the key point we emphasize is whether the patient feels cold or hot, rather than using body temperature as the sole standard; it is not about measuring temperature with a thermometer. In the context of cold and heat, there are two aspects: cold and heat. ◎ColdCold refers to the subjective feeling of being cold, where the patient feels a chill. This is a self-perceived sensation and is a matter of inquiry. However, we can also use palpation and pressure diagnosis to check the temperature of the patient’s forehead, limbs, and abdomen, or even use a thermometer to measure it. This belongs to our clinical data, but it is not the focus of the inquiry; the inquiry is about the patient’s own feelings, and cold refers to the patient’s own sensation of feeling cold. Cold can be divided into three types. One type is “evil wind,” which means feeling cold when encountering wind, and avoiding it can alleviate the sensation. Some people feel cold even on hot days when a fan is turned on; they cannot tolerate the wind from the fan. This is sometimes referred to as evil wind, which can be alleviated by avoiding it. The second type is called “evil cold.” Evil cold refers to the subjective feeling of being cold, where adding clothing or blankets or warming up does not alleviate the sensation. For example, if a patient feels cold, they might put on more clothes or cover themselves with a blanket, or warm themselves by the fire, but they still feel cold. This is what we call evil cold. The third type is “fear of cold,” which also refers to the subjective feeling of being cold, but in this case, the sensation can be alleviated by adding clothing or blankets or warming up. They feel a bit cold, but putting on more clothes or covering with a blanket alleviates the sensation. We categorize evil cold and fear of cold into these three types, with the latter two being human-defined distinctions. What is the difference in meaning? Evil cold usually refers to new or sudden occurrences, while fear of cold refers to chronic or long-term conditions. The purpose is to aid in pattern differentiation, which is beneficial for diagnosis. When describing symptoms, for instance, if a patient frequently experiences evil cold that is alleviated by adding clothing or blankets, we can simply refer to it as fear of cold, indicating that it is a long-term sensation. If it suddenly appears, such as feeling cold after a good day yesterday, then we would describe it as evil cold. ◎HeatHeat refers to the subjective feeling of warmth in the whole body or in specific areas. This is a self-perceived sensation of the patient, where they feel hot all over or in a specific area, such as the palms or a sore throat. They might feel a burning sensation in the throat or a hot feeling in the nose, indicating localized heat. Often, when we measure their temperature or palpate, we can also feel heat, which is considered a sign of fever. Why do patients experience feelings of cold and fever? The mechanisms behind evil cold and fever, or the sensations of cold and heat, can be understood from two aspects: one is the nature of the pathogenic factors, which can reflect the nature of the pathogenic qi causing the illness; the second reflects the balance of yin and yang within the body. The internal state of yin and yang can be reflected through the symptoms of cold and heat, thus mainly reflecting the nature of the pathogenic factors and the balance of yin and yang in the body. Since cold is considered a yin pathogen, it often manifests as a feeling of cold or evil cold; heat is considered a yang pathogen, which easily leads to fever. Therefore, diseases characterized by fever are generally considered heat syndromes, while those characterized by cold are generally considered cold syndromes. From the perspective of the internal balance of yin and yang, when there is a change in the balance of yin and yang within the body, feelings of cold or heat can arise. The mechanism is as mentioned in the Huangdi Neijing, which states, “When yang is excessive, there is heat; when yin is excessive, there is cold; when yin is deficient, there is heat; when yang is deficient, there is cold.” This is not caused by pathogenic factors; if it is a pathogenic factor, cold pathogens generally lead to cold syndromes, while heat pathogens lead to heat syndromes. When yang is too strong, the yang qi in the body is excessive, not due to pathogenic factors, but rather due to the abundance of yang qi; when yin qi is too abundant, it can lead to feelings of cold; when yang qi is insufficient or deficient, it can lead to feelings of heat; when yin qi or yin fluids are insufficient, it can also lead to feelings of heat. This mechanism can be reasoned from both the perspective of pathogenic factors and the balance of yin and yang. So how do we inquire about cold and heat? In the inquiry process, we mainly need to ask about the subjective feelings of the patient, emphasizing that their subjective experience is primary: do you feel cold or hot? Some patients may have a high temperature, but they still feel cold and do not feel feverish; others may not have a high temperature but feel feverish. Therefore, we should prioritize their subjective feelings while also conducting objective examinations. When inquiring, we need to pay attention to whether there is a feeling of cold or heat, and whether they occur simultaneously or separately. Is there only a feeling of cold? Is there only a feeling of fever? If there is only a feeling of cold without fever, then it is certainly separate; or if there is only fever without feeling cold, that is also separate. Some patients may experience both cold and fever simultaneously. We need to ask about the duration: how long has it been? Is it a new occurrence or a chronic condition? What is the degree of the sensation? Is it very severe? Do you feel cold a little, or is it just a slight chill? When the wind blows, do you feel cold, or are you fine indoors? This would be classified as evil wind, wouldn’t it? We need to clarify this situation. What is the duration and are there any specific time characteristics? Some patients may have fever at specific times, such as at night or during certain hours. In ancient times, there was a saying, “The back feels cold like the palm of a hand,” indicating that when there is internal cold, there may be a specific cold area on the back. What is the relationship between subjective and objective sensations? Measure the temperature; is it now 38°C or 39°C? What is your feeling, cold or hot? How do the subjective and objective sensations relate? What is the relationship between the head, torso, and extremities? Check the head, chest, abdomen, and extremities through palpation. If the head is hot, the hands and feet are cold, or the chest and abdomen are hot, we need to see how these three parts relate to each other. What are the conditions for the increase and alleviation of symptoms? Under what circumstances does the fever occur? Some patients say they feel hot when they are anxious; when they feel anxious, it feels like a fire rises, and they feel the need to take off their clothes and sweat. This indicates a relationship with psychological factors. What are the conditions for alleviation? Finally, we need to ask if there are any accompanying symptoms. What symptoms are closely related to evil cold and fever? Therefore, this inquiry about cold and heat can yield a lot of information, potentially leading to ten or more questions! Thus, we advise students not to stop at just asking if the patient has a fever; they should continue to ask further questions. Types of Cold and Heat The types of cold and heat can be divided into four categories. ◎Evil Cold and Fever What is Evil Cold and Fever? It refers to the simultaneous presence of both evil cold and fever in the patient, where the patient feels both cold and hot at the same time. These two symptoms, one of feeling cold and the other of fever, coexist in the same person, and they feel both sensations. This symptom is characteristic of exterior syndromes. When we talk about evil cold and fever, feeling both cold and hot is a characteristic manifestation of exterior syndromes. Logically, one would think that feeling cold and hot are two extremes, as one belongs to yang and the other to yin, and they should not coexist. However, in reality, they do exist. Let’s analyze this phenomenon of simultaneous cold and fever in clinical practice. It can be summarized into several situations: One situation is when the patient feels both cold and hot at the same time. When asked, “Do you feel cold?” they say yes, but they also feel hot. When asked if they feel cold, they might say they feel a bit cold, and when asked if they feel hot, they might say they feel hot. The second situation is when they feel cold at times and hot at other times. They might feel cold for a while and then feel hot, alternating between the two sensations. The third situation is when they feel cold when undressed and hot when dressed. They feel cold, but when they put on clothes, they feel hot and want to take them off. This is also a manifestation of evil cold and fever. The fourth situation is when a patient feels cold subjectively, but objectively they have a fever. They say they feel cold, but when their temperature is measured, it is high. Strictly speaking, this fourth situation does not belong to the category of evil cold and fever, as it refers to the patient feeling cold while the temperature is elevated. However, some may analyze this as a form of evil cold and fever, but I believe this fourth situation does not fit our inquiry about the simultaneous presence of evil cold and fever.Why do evil cold and fever coexist? The mechanism is due to the invasion of external pathogens, where the six excesses invade the body’s surface. The righteous qi and the evil qi are in conflict, and this conflict occurs at the surface of the body. This indicates that the righteous qi is unable to disperse, which is a manifestation of the conflict between the righteous and the evil qi. The conflict between the righteous and the evil qi indicates that a battle has begun, which will certainly lead to fever, but the righteous qi is unable to disperse, and thus the symptoms of cold and heat arise. This is a reflection of the body’s response to the invasion of external pathogens. Both evil cold and fever are manifestations of the body’s response to the invasion of external pathogens. They are both reactions of the righteous qi against the evil qi. The reason for feeling cold is to conserve energy, closing the pores to prevent the yang qi from dispersing, thus increasing energy. The reason for feeling hot is the righteous qi fighting against the evil. Therefore, whether it is feeling cold, fever, pain, or sneezing, all these symptoms are responses to the invasion of external pathogens. They reflect the struggle between the righteous and the evil qi. As stated in the Suwen, “When the pores are open, there is sweating and cold; when they are closed, there is heat and oppression.” Why do we feel both cold and hot? It is due to the opening and closing of the pores. When they are open, the external pathogens invade, leading to a feeling of cold; when they are closed, heat accumulates, resulting in a feeling of heat. This is the mechanism of evil cold and fever. Classification of Evil Cold and Fever The classification of evil cold and fever itself also requires further categorization. The first major category is the simultaneous presence of evil cold and fever. When this occurs, we need to further differentiate the severity of evil cold and fever, determining which sensation is more pronounced: the feeling of cold or the feeling of heat. This differentiation helps us understand the nature of the external pathogens. The first type is when evil cold is severe and fever is mild. The patient feels very cold, and when asked, they say they feel cold and have a slight fever. They feel very cold, but the fever is not very pronounced. This indicates a wind-cold exterior syndrome. The mechanism is clear: because cold is constricting and binding, when the cold pathogen invades the surface of the body, the skin and pores are in a closed state, causing the yang qi at the surface to be insufficient, leading to the sensation of cold. The second situation is when fever is mild and evil wind is present. There is a slight fever, and we use the term evil wind, which we have discussed before, meaning feeling cold when encountering wind, and avoiding it can alleviate the sensation. When there is no wind, the patient does not feel cold. This indicates a mild exterior syndrome. The wind is a light manifestation of cold, and the fever is also mild, indicating a wind-cold exterior syndrome. The nature of wind is to disperse, and the skin and pores are in a relaxed state, so the conflict between the righteous and the evil qi is not very intense, thus reflecting a mild evil wind and mild fever. The third situation is when fever is severe and evil cold is mild. The patient has a more pronounced fever, and when asked if they feel cold, they say they feel a little cold, but the fever is very obvious. This indicates a wind-heat exterior syndrome. All three situations involve wind pathogens, but this one leans more towards heat. The wind-heat pathogen is a yang pathogen, and when yang is excessive, it manifests as heat. The wind-heat pathogen causes the skin and pores to be relaxed, so there is still a slight feeling of evil cold. We need to analyze the phenomenon of evil cold and fever and recognize several key points: First, the simultaneous presence of evil cold and fever is a characteristic symptom of exterior syndromes. It involves both the righteous and the evil qi, and the relationship between the two is crucial. The nature of the pathogenic qi, whether it is a cold or heat pathogen, and the severity of the pathogenic qi are important factors. The state of the yang qi, whether it is strong or weak, and the state of the righteous and evil qi are also significant. Therefore, it involves four points: the nature of the pathogenic qi, the severity of the pathogenic qi, the strength of the yang qi, and the state of the righteous and evil qi. Due to these factors, we generally see that when the pathogenic qi is mild, the symptoms of evil cold and fever are also mild. For example, in cases of evil wind or wind-cold, the pathogenic qi is relatively mild. When the pathogenic qi is severe, such as in cases of heat or cold pathogens, the symptoms of evil cold and fever are more pronounced. When both the righteous and evil qi are strong, the symptoms of evil cold and fever are generally more obvious. When the evil qi is strong and the righteous qi is weak, the symptoms of evil cold are often more pronounced than the fever. Thus, we see that the presence of evil cold and fever is not merely a matter of experiencing pathogenic qi; it is also closely related to the state of the righteous qi. For instance, we often observe that individuals with weak constitutions may experience external pathogens without a significant fever, while those with strong constitutions may develop a high fever quickly. For example, in the same environmental conditions, if the weather suddenly turns cold, some people may catch a cold and develop a fever, while others may only feel cold without a fever. This indicates that the response to external pathogens varies based on individual constitution and inherent conditions. The question of whether the pathogenic qi manifests as heat or cold is influenced by the individual’s constitution. Second, the simultaneous presence of cold and heat is an important basis for diagnosing exterior syndromes. To diagnose an exterior syndrome, the presence of evil cold is essential. If a patient reports no feeling of evil cold, then they do not have an exterior syndrome. The diagnosis of an exterior syndrome requires the presence of evil cold, which may occur alone or in conjunction with fever. The Shanghan Lun states, “In exterior syndromes, there may be fever or no fever, but there must be evil cold.” Evil cold is a necessary condition; the presence of fever is optional. Therefore, later interpretations suggest that “where there is a degree of evil cold, there is a degree of exterior syndrome.” If a patient has even a slight feeling of cold, it indicates the presence of an exterior syndrome; if there is no feeling of evil cold, it suggests the absence of an exterior syndrome. These two statements are important to remember: In the Yijian, it states, “In external conditions, cold and heat occur simultaneously without intervals; in internal injuries, cold and heat occur alternately and not simultaneously.” What does this mean? It is a crucial basis for distinguishing between external and internal conditions. If it is an external condition, “cold and heat occur simultaneously without intervals,” meaning that both evil cold and fever are present at the same time, not alternating. In contrast, in internal injuries, cold and heat can occur alternately, meaning that a patient may feel cold at one moment and hot at another, but not simultaneously. This distinction is essential for diagnosis. Therefore, the simultaneous presence of cold and heat is a key indicator of exterior syndromes, while internal injuries may present with alternating cold and heat symptoms. What is Evil Wind? Evil wind refers to feeling cold when encountering wind, and avoiding it can alleviate the sensation. What are Evil Cold and Fear of Cold? Evil cold specifically refers to a sudden onset of cold sensation, while fear of cold refers to a long-term, chronic feeling of cold that can be alleviated by adding clothing or blankets, often indicating a deficiency of yang qi. What are Strong Heat and Tidal Heat? Strong heat refers to a high fever that persists without subsiding, while tidal heat refers to fever that occurs at specific times or intensifies at certain times. Strong heat is associated with excess heat syndromes, while tidal heat is related to the depth of the pathogenic qi and the timing of the fever. Why does Evil Cold not resolve with warmth? Why does exposure to wind and cold lead to fever? These phenomena can be understood through the conflict between the righteous and evil qi, as well as the state of the pores and the body’s response to external pathogens. The conflict between the righteous and evil qi explains why one may feel cold and why warmth does not alleviate the symptoms. What causes mild fever? Mild fever can arise from various causes, including qi deficiency, blood deficiency, yin deficiency, or a combination of qi and yin deficiency. It is essential to consider the overall symptoms to determine the underlying cause of the mild fever. What is Cold and Heat Alternating? Cold and heat alternating refers to the clear and distinct alternation of cold and heat symptoms, which can be classified into two types: those without fixed timing and those with fixed timing, often indicating a half-exterior, half-interior syndrome.