Summary: Ye Tianshi distinguished warm diseases from cold damage, and Xue Shengbai further separated damp-heat diseases from warm diseases. Xue Shengbai, also known as Xue Xue, is the foremost expert in treating damp-heat diseases throughout history! His work, “Damp-Heat Disease Chapter,” has become the standard for treating damp-heat diseases in later generations! The renowned TCM scholar Ren Yingqiu commented on the “Damp-Heat Disease Chapter,” stating: “Damp-heat diseases are highly variable; those who grasp the key to their treatment are rare, and it is especially important to study it and not neglect it.” Xue Shengbai classified damp-heat diseases into exterior syndrome, half-exterior half-interior syndrome (i.e., evil hidden in the membrane source syndrome), and interior syndrome, with a focus on learning to diagnose and treat damp-heat interior syndrome, explained below:
1. 【Composite Etiology】
1. Damp-heat disease is caused by the external invasion of both dampness and heat evils, which mix together to cause illness. Therefore, the invading evils exhibit characteristics of both dampness and heat. Dampness, being yin, has the properties of “descending and being sticky,” thus it often invades the lower parts of the body and easily obstructs the flow of qi, damaging yang qi. Heat, being yang, has the properties of “ascending and burning,” thus it often invades the upper parts of the body and easily consumes yin blood, disturbing the spirit. Dampness is yin evil, and heat is yang evil; the simultaneous invasion of these two oppositely attributed evils leads to illness, where heat resides within dampness, and dampness surrounds heat, akin to oil in flour, making them difficult to separate. Xue Shengbai stated: “Heat is the qi of heaven, and dampness is the qi of earth; when heat encounters dampness, it becomes more intense, and when dampness encounters heat, it becomes more rampant. If dampness and heat are separated, the illness is mild; if dampness and heat are combined, the illness is severe and rapid.” Wang Mengying also said: “When heat encounters dampness and is obstructed, it becomes more intense; when dampness encounters heat, it steams and rises, thus becoming more rampant. The combination of the two evils leads to the most illnesses.”
2. Dampness, being yin and associated with water, and heat, being yang and associated with fire, are opposites and contradictory; thus, damp-heat disease is a unity of contradictions, often presenting contradictory symptoms in clinical practice. For example: fever, yet the face is not red but pale yellow; fever, yet the pulse is not rapid but slow; fever, yet the spirit is not agitated but dull; fever, yet the tongue coating is not yellow but white; fever, yet the stool is not dry but loose.
2. 【Pathogenesis of Damp-Heat】
Xue Shengbai stated: “Taiyin injury leads to the accumulation of dampness and phlegm, and when external evils invade, they attract each other, thus causing damp-heat disease.” Taiyin refers to the spleen, meaning that factors such as irregular diet damage the spleen, leading to spleen deficiency. When the spleen is deficient, its ability to transform and transport fluids is weakened, causing fluids to accumulate and produce dampness. If external damp-heat is encountered, the internal dampness will attract the external damp-heat into the spleen, resulting in damp-heat disease. Thus, spleen deficiency is the pathological basis for the development of damp-heat disease. If the spleen is not deficient, then damp-heat will not enter the spleen, and the person will not suffer from damp-heat disease. By understanding the pathogenesis of damp-heat disease, we can identify the tongue manifestations associated with the disease. When there are symptoms of spleen deficiency, the tongue is red with a white coating, indicating the invasion of damp-heat evil, primarily damp-heat disease. When there are no symptoms of spleen deficiency, the tongue is red with a white coating, indicating heat transforming fluids into phlegm, primarily heat-phlegm.
3. 【Center of Pathological Changes】
Xue Shengbai stated: “The damp-heat evil enters the body through the surface in 10-12% of cases, while 80-90% enter through the mouth and nose.” This means that the pathways for damp-heat evil to invade the body are through the skin and the mouth/nose, with the opportunity for entry through the skin being less than through the mouth/nose. The mouth connects to the stomach, and the nose connects to the lungs, indicating that once the damp-heat evil enters the body, it can affect the lungs or the stomach. Xue Shengbai also stated: “Evil enters from above and directly reaches the middle path, thus the disease often returns to the membrane source.” This means that when damp-heat evil enters through the mouth and nose, it directly affects the spleen and stomach, often passing through the membrane source, thus the likelihood of developing membrane source syndrome is high. This also indicates that the opportunity for damp-heat evil to enter the lungs is low, while the opportunity to enter the membrane source is high. The membrane source is located neither on the surface nor deep inside, but in a half-exterior, half-interior position, specifically between the skin and the stomach. After the damp-heat evil enters the body through the mouth and nose, Zhang Xugu stated: “It first affects the membrane source and ultimately returns to the spleen and stomach.” This means that when damp-heat enters through the mouth and nose, the first manifestation is membrane source syndrome, while when it enters through the skin, the first manifestation is skin exterior syndrome, followed by membrane source syndrome. However, whether it enters through the mouth and nose or through the skin, after membrane source syndrome appears, it follows the same pattern of progression from superficial to deep, ultimately affecting the spleen and stomach, leading to spleen and stomach pathology. From the above, it can be seen that the damp-heat evil causes disease, with the chances of skin and lung pathology being low, while the chances of spleen and stomach pathology are relatively high; thus, damp-heat disease centers around spleen and stomach pathology. Zhang Xugu also informed us of the reasons why damp-heat evil enters the spleen and stomach, stating: “The stomach is the earth of Wu, belonging to yang, and the spleen is the earth of Ji, belonging to yin; the qi of damp earth attracts each other, thus the damp-heat evil, although initially received from the outside, ultimately returns to the spleen and stomach.” This means that the stomach is the earth of Wu, belonging to yang, and the spleen is the earth of Ji, belonging to yin. Both the spleen and stomach belong to earth, and earth and dampness attract each other, thus the damp-heat evil, although initially received from the outside, ultimately returns to the spleen and stomach.
4. 【Diffusion in the Three Jiao】
Damp-heat disease, although centered on spleen and stomach pathology, can also involve other organs due to the characteristic of dampness to diffuse downward. If damp-heat is stagnant and obscures the upper, causing obstruction of the clear orifices, it can lead to confusion of consciousness; if dampness descends and accumulates in the bladder, it can cause urinary difficulties; if damp-heat accumulates in the liver and gallbladder, it can lead to jaundice; if damp-heat accumulates in the muscles, it can cause heaviness and joint pain.
5. 【Determination Criteria】
Xue Shengbai stated: “Damp-heat disease is not only different from cold damage but also very different from warm diseases.” How do we know if it is damp-heat disease? It is determined based on the key symptoms of damp-heat disease. Xue Shengbai listed the key symptoms of damp-heat disease in the “Damp-Heat Disease Chapter,” which states: “Damp-heat syndrome begins with aversion to cold, followed by heat without cold, sweating, chest fullness, white tongue coating, and thirst without desire to drink.” This means that if a patient initially has aversion to cold, later only has fever without aversion to cold, sweats, experiences chest fullness, has a white tongue coating, and thirst without a desire to drink, it can be determined as damp-heat disease. One must memorize the key symptoms of damp-heat disease; otherwise, it is impossible to determine if it is damp-heat disease.
6. 【Key Pathogenesis】
Xue Shengbai proposed six typical symptoms of damp-heat disease, and the pathogenesis of these six typical symptoms is analyzed as follows:
1. Initial aversion to cold: The damp-heat evil, with more dampness than heat, invades the surface, and the yang qi at the surface is obstructed by damp evil, thus the yang qi cannot circulate, leading to initial aversion to cold.
2. Later only heat without cold: The damp-heat evil, with more dampness than heat, invades the surface, and the yang qi at the surface is gradually transformed into heat due to prolonged obstruction by damp evil, thus later only fever without aversion to cold.
3. Chest fullness: Refers to chest tightness and abdominal distension. Damp-heat obstructs the qi mechanism of the middle jiao, leading to abdominal distension. Damp-heat obscures the chest yang, thus causing chest tightness.
4. Sweating: The “Neijing” states: “Yang added to yin is called sweat,” and the yangming stomach heat is abundant, thus sweating occurs.
5. White tongue: In the early stage, with more dampness than heat, damp evil is abundant, thus the tongue coating is white. If dampness gradually transforms into heat, the tongue coating will turn yellow.
6. Thirst without desire to drink: Damp-heat obstructs the middle jiao, preventing fluids from ascending, leading to dryness in the mouth and thirst. When water and fluids are abundant, there is no desire to drink.
7. 【Mastering Characteristics】
In diagnosing damp-heat disease, it is essential to grasp the following basic characteristics:
1. Fever: Manifesting as body heat without elevation, or afternoon heat.
2. Thirst without desire to drink: Initially, the mouth is sticky but not thirsty, or thirsty without a desire to drink water.
3. Chest fullness: Often feeling chest tightness and abdominal distension.
4. Systemic symptoms: Damp-heat disease centers on spleen and stomach pathology, and since the spleen governs the muscles and limbs, there will also be symptoms of heaviness and fatigue in the limbs, and muscle discomfort.
5. Diet: Poor appetite, or accompanied by nausea and vomiting.
6. Urination and defecation: Urine is scant and turbid. Stool is often loose and abundant, or sticky and difficult to pass.
8. 【Transformation of Pathogenesis】
1. The damp-heat evil enters the body through the surface; initially, the wei level syndrome is characterized by dampness obstructing the wei qi, with damp-heat being heavy in dampness and light in heat, and prolonged dampness gradually transforms into heat.
2. The damp-heat evil enters the body through the mouth and nose; since damp-heat disease centers on spleen and stomach pathology, the transformation of the pathogenesis and clinical symptoms related to the middle qi deficiency and excess are closely related. The transformation of the damp-heat evil entering the middle jiao can be divided into three situations.
(1) Heavy dampness and light heat: Xue Shengbai stated, “If the middle qi is deficient, the disease is in the Taiyin.” This means that if the spleen yang is inherently deficient, the damp-heat evil entering the middle jiao is likely to transform towards dampness, with the pathology primarily in the Taiyin spleen, presenting as heavy dampness and light heat. If it continues to develop, spleen dampness will damage kidney yang, leading to spleen earth overpowering kidney water, resulting in kidney yang deficiency.
(2) Heavy heat and light dampness: Xue Shengbai stated, “If the middle qi is excess, the disease is in the Yangming.” This means that if the stomach yang is inherently strong, the damp-heat evil entering the middle jiao is likely to transform towards heat, with the pathology primarily in the Yangming stomach, presenting as heavy heat and light dampness. If it continues to develop, stomach heat will damage kidney yin, leading to stomach earth overpowering kidney water, resulting in kidney yin deficiency.
(3) Equal dampness and heat: If the middle yang is neither excessively strong nor weak, the pathology is in the spleen and stomach, presenting as equal dampness and heat.