The surgical diseases occur mostly on the body surface and are easy to be diagnosed. But, each disease is caused by its different pathogenic factor. Due to the different pathogenic factors, the therapeutic principles are also different. Therefore, it is necessary to identify the various pathogenic factors of the surgical diseases carefully, in order to establish the therapeutic plan and enhance the therapeutic effect.

The diseases caused by six exogenous pathogenic factors are mostly seasonal. For instance, wind and warmth, and wind and heat are more frequent in the spring. Pathogenic wind is a yang pathogenic factor and constant in motion and rapid in change. Therefore, the onset is swift and mostly belongs to yang syndrome. Wind is characterized by tending to flow upwards and mostly attacks the upper part of the human body, such as carbuncles on the neck and erysipelas on the face and head. 

The features of the diseases caused by pathogenic wind are superficial tumefaction, pruritus or wandering pain with swift migration. The dermal pathological changes are characterized by dry nature. Or although the supportive fluid discharges, the ulcer heals immediately after it breaks. The anorectal diseases are often manifested by hematochezia, in a gushing discharge and bright red color. Summer heat prevails mostly in the summer. Due to external invasion, summer heat can steam and burn the skin to cause profuse sweating, and leading to disease, or to cause non-smooth perspiration, and leading to heat rash. 

If scratched repeatedly, the skin breaks and gets infected to produce summer furuncles, and even induce multiple abscess of summer dampness.If summer heat is mixed with dampness to saturate the skin, it is easy to cause various types of eczema. If pathogenic dampness and heat are accumulated in the anus, it is possible to induce anorectal abscess. Summer heat is a yang pathogenic factor, characterized by pruritus due to slight heat, pain due to excessive heat, and suppuration due to excessive heat. 

Therefore, the diseases caused by it are mostly yang syndromes, manifested by tumefaction in red color and burning pain, easy suppuration, or erosion, discharge of suppurative fluid, and often accompanied by fever, thirst, stuffy chest and poor appetite. In addition, because of hot weather in the summer, lack of enough sleep and food, the body resistance is relatively weak. Therefore, the incidence of the surgical diseases is far higher in the summer than in other seasons. Pathogenic dryness prevails in the autumn and characterized by dry nature. 

If the skin is damaged by it, the exogenous pathogenic factors can take the advantage to invade the human body to cause the surgical diseases, or the dermal and anorectal diseases of rhagas and anal fissure, and often accompanied by general symptoms of dry mouth, dry lips and dry throat. Pathogenic cold prevails in the winter and attacks the human body to cause local stagnation of qi and blood and obstruction of the meridians, resulting in frostbite and gangrene in the fingers and toes. Pathogenic cold is a yin factor and easily damages yang qi of the human body. If tumefaction is caused by it, it is neither red nor heat, and in a diffuse tendency, often accompanied by aversion to cold, cold sensation in the four limbs, and urine in clear and large volume. 

Mixed with pathogenic summer heat, pathogenic dampness prevails also in the autumn and tends to attack the lower part of the human body, mainly manifested by erosion and discharge of suppurative fluid, and long duration, such as eczema and tineacorporis. Pathogenic fire is often accompanied by pathogenic heat. There is no obvious difference in their natures and causative features. They are only different in their severity. Namely, pathogenic fire is a progress of pathogenic heat and pathogenic fire is a high peak of pathogenic heat.

Specific toxins include insect poison, snake poison, rabies poison, drug poison and food poison, etc. In the surgical diseases, dermatitis by insect bite, snakebite and rabies can be caused by insect and animal bites and invasion of specific poisons. Due to constitutional intolerance in some people, exposure to paints can also cause allergic dermatitis. Some foodstuffs can also induce similar diseases.

In the surgical diseases, the open injury of the skin and membrane is an important channel for pathogenic factors to invade the body. The closed injury of the muscles and bones is one of the basic factors for occurrence of multiple abscess and pyogenic infection of bones. Because of the obstruction in the meridians after injury, qi and blood are unable to flow smoothly, leading to stagnation. Moreover, boiling water, flame, ice and snow that harm the human body can cause the diseases of burn and congelation.

Prolonged or excessive emotional irritation can cause the dysfunction of Zang-fu organs of the human body. The disturbance of qi activity and dysfunction in ascending and descending ability can cause metabolic disturbance of humor, qi and blood, leading to qi stagnation, phlegm and stagnant blood, and in addition can also cause secretary and metabolic disturbance of latex, resulting in breast abscess, and scrofula. And severe conditions can even in- duce tumors.

Indulgence in greasy and sweet food, alcoholic drinks or spicy food can cause dysfunction of the spleen and stomach and produce pathogenic dampness, heat and fire, which can easily result in abscess, carbuncle and furuncle, etc. The diseases induced internally are relatively severer than those caused simply by external pathogenic factors. Brandy nose and ache in the dermal diseases and hemorrhoids in the anorectal diseases are all related to improper food, excessive intake of alcoholic drinks or spicy and irritating foodstuffs.

Sexual impairment mainly includes the implication in two aspects. On one hand, it refers to early marriage, early pregnancy and excessive coitus, or excessive delivery, which can lead to damage of essential qi in the kidney, deficiency of the kidney qi, or dysfunction of the thoroughfare and conception vessels.  When the ant pathogenic ability of the human body becomes low, it is easy to be sick with the surgical diseases. 

Because the kidney dominates the bone, the deficiency of the kidney can cause emptiness in the bones and then the pathogenic wind, cold and turbid phlegm can take the advantage to enter the body to result in the diseases of tuberculosis in the bones and joints. On the other hand, it refers that the diseases are difficult to be cured, if the kidney essence is damaged due to excessive coitus in the sick constitution. For instance, it is requested to control sexual activity, in lupus erythematosus and gangrene in the fingers and toes. Otherwise, it is easy to aggravate the diseases and even bring about critical conditions.

Various pathogenic factors mentioned above can cause diseases individually and also several pathogenic factors can lead to diseases together. Furthermore, there is also certain relation between the pathogenic factors and the position of the diseases. For instance, the diseases happening on the upper part of the human body (head, face, neck, and upper limb) are mostly caused by wind and warmth, and wind and heat, because pathogenic wind tends to flow upwards. 

The diseases happening in the middle part of the human body (chest, abdomen, lumbus, and back) are mostly related to stagnation of qi and accumulation of fire, because pathogenic fire prevails in the middle. The diseases happening in the lower part of the human body (hip, leg, calf, and foot) are induced mostly by cold and dampness, and dampness and heat, because pathogenic dampness tends to flow downwards. Therefore, in the diagnosis of disease, it is necessary to make a comprehensive analysis by consideration of the local and general symptoms and history, in order to obtain a correct conclusion on etiology and pathogenesis.