Differentiation of Exterior and Interior Syndromes in Traditional Chinese Medicine (8th Edition)

The differentiation of exterior and interior syndromes is a method for identifying the location of disease, the severity of the condition, and the trend of the disease. It focuses on distinguishing between internal and external disease locations and the depth of the disease. The skin, muscles, and meridians are considered external (biao), while the five organs and six bowels are internal (li). This differentiation is applicable to externally contracted diseases, as it allows for the assessment of the severity and depth of the condition and the trend of pathological changes. Exterior syndromes are superficial and mild, while interior syndromes are deep and severe. When an exterior pathogen enters the interior, the disease progresses; when an interior pathogen exits to the exterior, the disease retreats. Understanding the severity and progression of the disease enables one to grasp the evolution of the condition and take the initiative in treatment, serving as the basis for methods such as releasing the exterior and attacking the interior.

Exterior Syndrome (Biao Zheng)

Exterior syndrome refers to a type of syndrome where the disease is superficial, located in the skin and muscles. It is caused by the invasion of external pathogens (the six excesses) through the skin and orifices, marking the initial stage of externally contracted diseases. Exterior syndromes typically present with sudden onset, short duration, and superficial location. The clinical manifestations include fever, chills (or aversion to wind), body aches, thin white tongue coating, and floating pulse as the main symptoms. Other symptoms may include nasal congestion, runny nose, itchy throat, and cough.

Syndrome analysis: The six excesses invade the skin and muscles, obstructing the normal dispersal of defensive qi (wei qi), leading to heat. When the defensive qi is obstructed, the skin and muscles cannot receive normal warmth, resulting in symptoms of aversion to wind and cold. The pathogenic qi stagnates in the meridians, causing obstruction of qi and blood flow, leading to body aches. If the pathogen has not entered the interior, the tongue appearance shows no significant changes, presenting with a thin white coating. When the external pathogen invades, the righteous qi rises to resist the pathogen, hence the pulse is floating. The lungs govern the skin and hair, and the nose is the orifice of the lungs; thus, the pathogen enters through the skin and orifices, affecting the lungs, leading to symptoms such as nasal congestion, runny nose, itchy throat, cough, and even wheezing.

Interior Syndrome (Li Zheng)

Interior syndrome refers to a type of syndrome where the disease is deep within the internal organs (zang-fu, qi, and blood). Interior syndromes can arise from unresolved exterior pathogens that penetrate inward, invading the internal organs; or from direct invasion of pathogens into the internal organs; or from other causes such as emotional distress, improper diet, or overexertion, leading to dysfunction of the internal organs.

Interior syndromes encompass a wide range of syndromes, with diverse clinical manifestations, primarily characterized by symptoms related to the internal organs. Interior syndromes typically have a longer duration, lack aversion to wind and cold, and the pulse is not floating, allowing differentiation from exterior syndromes. Specific details can be found in the sections on differentiation of deficiency and excess, cold and heat, and zang-fu differentiation.

Common symptoms of interior syndromes include high fever, irritability, delirium, thirst, abdominal pain, constipation or diarrhea, vomiting, short and red urination, yellow or thick white tongue coating, and deep pulse.

Symptom analysis: Heat pathogens penetrate into the interior, or cold pathogens transform into heat within, leading to intense heat; heat damages body fluids, resulting in thirst and short red urination; heat disturbs the mind, causing irritability and delirium. If cold pathogens directly invade the internal organs or cold dampness directly attacks the spleen and stomach, cold pathogens stagnate in the middle jiao, causing abdominal pain; cold dampness obstructs the spleen and stomach, leading to diarrhea; if the stomach loses its harmony and descent, vomiting occurs, with yellow or thick white tongue coating and deep pulse indicating the disease is in the interior.

Relationship Between Exterior and Interior Syndromes

1. Simultaneous Exterior and Interior Disease When exterior and interior syndromes appear simultaneously, it is referred to as simultaneous exterior and interior disease. For example, if a patient presents with fever, chills, headache, and absence of sweating (exterior symptoms), along with abdominal distension, constipation, and yellow urination (interior symptoms), this is a case of simultaneous exterior and interior disease. This is commonly seen when the exterior syndrome has not resolved, and the pathogen has entered the interior, or when the pathogenic factors simultaneously invade both the exterior and interior, or in cases where an old illness has not healed and is re-exposed to external pathogens. Common patterns include exterior cold with interior heat, exterior heat with interior cold, exterior deficiency with interior excess, and exterior excess with interior deficiency.

2. Transformation Between Exterior and Interior Exterior and interior syndromes can also transform into one another, known as “entering from the exterior to the interior” and “exiting from the interior to the exterior.” The transformation between exterior and interior syndromes is conditional, primarily depending on the state of the struggle between righteous and pathogenic qi. When the body’s resistance decreases, or when pathogenic qi is excessive, or due to improper care or mismanagement, exterior syndromes can transform into interior syndromes. For instance, if an external pathogen remains unresolved, the condition may progress to high fever that does not subside, cough with yellow thick or bloody phlegm, indicating that the pathogenic factor has entered the interior, obstructing the lungs, forming a pattern of phlegm-heat obstructing the lungs; if treated promptly, the patient’s fever gradually subsides, and cough and wheezing improve, indicating that the interior pathogen has exited to the exterior. When the pathogenic factor enters the interior, it indicates a worsening condition; when the pathogenic factor exits to the exterior, it indicates an improvement in the condition.

3. Half Exterior Half Interior When an external pathogen transmits inward but has not yet reached the interior, or when an interior syndrome emerges to the exterior but has not yet fully manifested, this condition is referred to as half exterior half interior syndrome (known as Shaoyang syndrome in the six meridian differentiation). Symptoms include alternating chills and fever, fullness in the chest and hypochondria, bitter taste in the mouth and dry throat, dizziness, irritability with nausea, and aversion to food, with a wiry pulse.

Electronic Textbook

Traditional Chinese Medicine – Renwei 8th Edition