For any disease, it is rare that there is no fever. The key distinction between internal injury (Neishang) and external contraction (Waigan) lies in the pulse: if the Renying pulse (Renying, located on the neck, belonging to the Foot-Yangming Stomach Meridian) is larger than the Qikou pulse (Qikou, located at the radial artery of the wrist, belonging to the Hand-Taiyin Lung Meridian), it is an external contraction; if the Qikou pulse is larger than the Renying pulse, it is an internal injury. In external contractions, aversion to cold and fever occur simultaneously without interruption; in internal injuries, aversion to cold and fever occur alternately and are not synchronized. Aversion to cold due to external contraction cannot be eliminated even by approaching a fierce fire; aversion to cold due to internal injury can be relieved by seeking warmth. Aversion to wind due to external contraction implies intolerance to all kinds of wind and cold; aversion to wind due to internal injury implies only fear of slight drafts. External contraction symptoms manifest in the nose, so nasal breathing is obstructed and breath is forceful and congested; internal injury symptoms manifest in the mouth, so taste is lost and the abdomen feels discordant. Due to excess pathogenic factors in external contraction, speech is loud and vigorous, starting light and becoming heavy; due to deficiency of healthy Qi (Yuanqi) in internal injury, speech is lazy and timid, starting heavy and becoming light. Headache from external contraction is constant; headache from internal injury comes and goes. Heat in the back of the hand with cool palms indicates external contraction; heat in the palms with cool backs of the hands indicates internal injury. Li Dongyuan's method of differentiation is generally as follows. Cases may have internal injury without external contraction, or external contraction without internal injury; distinguishing them this way makes the difference clear. If internal injury and external contraction coexist and combine, the pulse and symptoms appear together, making differentiation difficult, requiring careful investigation. If internal injury symptoms predominate, internal injury is severe and external contraction is mild; nourishment and tonification should take precedence. If external contraction symptoms predominate, external contraction is severe and internal injury is mild; dispersing and harmonizing should be urgent. This is another implication not explicitly stated by Li Dongyuan.

(Winter-warmth [Dongwen], Warm-pathogen disease [Wenbing], Cold-epidemic [Hanyi], Heat-disease [Rebing], Damp-warmth [Shiwen], Wind-warmth [Fengwen], Cholera-like disorder [Huoluan], Spasm [Jing], Food stagnation [Shangshi], Deficiency vexation [Xufan], Phlegm-fluid retention [Tanyin], Hongkong foot [Xianggangjiao], Internal abscess [Neiyong], Blood stasis [Xuxue])

It is commonly believed that Phlegm-fluid retention, Hongkong foot, and Deficiency vexation are four conditions resembling Shaoyang disease (Shaohang). Wang Shuhe also included Spasm, Dampness, and Cholera-like disorders resembling Shaoyang disease into the *Treatise on Cold Damage* (*Shanghan Lun*). However, comparing their manifestations and symptoms, there are more than just these categories. The cases of internal injury and fatigue resembling Shaoyang disease have been mentioned previously. Here, Winter-warmth and other diseases are analyzed and differentiated from Shaoyang disease and listed below. After Frost's Descent (Shuangjiang), when the weather becomes cold and frozen, contracting cold pathogens leads to Shaoyang disease (Floating-tight pulse without sweat indicates Shaoyang disease; Floating-slow pulse with sweat indicates Wind-injury). After Frost's Descent, if it should be cold but remains warm, leading to illness due to thin clothing and exposure to cold, it is called Winter-warmth (Seasonal qi causing macules, and warm pathogens encountered again while heat from Shaoyang disease has not subsided, is called Warm-toxin). In spring, when the heavenly climate is mild, someone may have high fever, thirst, and no aversion to cold; this is Warm-pathogen disease (Using acrid-warm diaphoretics would cause damage). (If the weather is still cold and ice/snow has not melted, contracting cold pathogens is also called Shaoyang disease). Between the third month and the eighth month, if sudden cold occurs in the climate, contracting cold pathogens leads to Seasonal Cold-Epidemic. After Summer Solstice, when the season is hot, someone may have high fever, restlessness, thirst, and no aversion to cold; this is Heat-disease. Heat-disease resembles Zhongshu (Heat-stroke), but Heat-disease has a full pulse, while Zhongshu has a deficient pulse. In summer, illness presenting with headache, delirium, spontaneous sweating, body not very hot, reverse coldness in both calves, heaviness in limbs, and fullness in chest/abdomen is Damp-warmth. Such individuals are often injured by dampness, then suffer heat-stroke; dampness and heat contend, causing this disease. Diaphoresis is contraindicated. Headache, body heat, and spontaneous sweating resemble Shaoyang disease, but the pulse is floating in both Cun and Chi positions, body is heavy, silence with desire to sleep, snoring breath, difficulty speaking, and inability to control limbs indicate Wind-warmth; diaphoresis is contraindicated. Vomiting with diarrhea, headache, body pain, aversion to cold and fever, or cessation of vomiting/diarrhea followed by fever, is Cholera-like disorder. Body heat, cold feet, stiffness and tension in head/neck, aversion to cold, occasional head heat, red face, red eye vessels, only head shaking, sudden jaw lock, and opisthotonos indicate Spasm. Aversion to cold without sweat is Gang-Jing (Rigid Spasm); aversion to wind with sweat is Rou-Jing (Soft Spasm). Lying on back with eyes open is Yang-Jing; lying on stomach with eyes closed is Yin-Jing. Floating-tight-rapid pulse is Yang-Jing; sinking-thin-choppy pulse is Yin-Jing. Dry mouth/thirst is Yang-Jing; normal mouth sensation is Yin-Jing. Yang-Jing is easy to treat; Yin-Jing is difficult. Headache and fever resembling Shaoyang disease but without body pain, with a tight/full Qikou pulse on the right hand, short/sliding Guan pulse on the right, and a peaceful left hand, indicates Food stagnation. Accompanied by epigastric stuffiness, belching with sour taste, aversion to food odor, desire to vomit but unable, or incomplete vomiting. There are cases where food stagnation combines with cold contraction, resulting in large Renying and Qikou pulses on both hands, vexation/heat resembling Shaoyang disease, but pulse not floating-tight, no headache, no body pain, no aversion to cold. Vexation with headache that ceases when vexation ceases indicates Deficiency vexation. Aversion to cold with fever, aversion to wind with spontaneous sweating, chest fullness, Qi rushing up to throat causing dyspnea, resembling Shaoyang disease but without headache or neck stiffness, with intermittent headache of irregular timing, and a tight but not large pulse, indicates Phlegm. Phlegm in Upper Jiao presents with sinking-sliding or sinking-hidden Cun pulse; Phlegm in Middle Jiao presents with large sliding Guan pulse on the right hand; Qi stagnation presents with sinking-sliding pulse; combined with food presents with short-sliding pulse. String-taut-sliding pulse indicates Phlegm-fluid retention; predominantly string-taut indicates Fluid retention; sinking-string-taut indicates Xuan-yin (Suspension fluid) and internal pain. Large pulses at Left/Right Guan, or floating-large at Guan, or dark circles under eyes like smoke, are signs of Phlegm. Fever, aversion to cold, headache, joint pain, nausea/vomiting, resembling Shaoyang disease, but starting in the feet, with swollen/painful ankles/knees, legs either swollen or emaciated, and hard stool, indicates Hongkong foot. *Shanghan Lun* states: Pulses that are floating and rapid usually accompany fever and chills. If there is a painful area but diet is normal, it indicates pus accumulation. This refers to Internal Abscess. *Suwen* states: Fullness in Liver, Kidney, or Lung, being excess, results in swelling. Wang Bing notes: "Fullness" refers to full/excess pulse Qi; "Swelling" refers to carbuncle/abscess swelling. Generally, cough with hidden chest pain, rough skin on chest/heart, chills, rapid pulse, dry throat without thirst, frequent expectoration of turbid foul-smelling sputum, and long-term expectoration of pus like rice gruel, indicates Lung Abscess. Heavy lower abdomen, pain upon firm pressure, frequent urination resembling strangury, periodic sweating with aversion to cold, rough skin like scales, tense abdominal skin resembling swelling, and slippery-rapid pulse, indicates Intestinal Abscess. Hidden pain in epigastrium, tenderness to touch, sinking-thin Stomach pulse, and reversed-full Renying pulse, indicates Gastric Abscess. Internal injury and external contraction are distinguished by Renying and Qikou pulses. Thus, in internal injury, the Renying pulse is peaceful, whereas in Gastric Abscess, the Renying pulse is surprisingly full. Mistaking the latter for Shaoyang disease is common; early differentiation is essential. A maiden from the Qian family in Jingkou suffered from intestinal abscess with fever. Quacks treated it as Shaoyang disease, forbade food and drink for over ten days, leading to death. On her deathbed, she discharged several liters of pus, revealing the abscess; rescue was impossible. Alas! How can one neglect reading Zhang Zhongjing's works? Fever resembling Shaoyang disease, but the patient has history of falling from height, trauma, or extreme anger/shouting, followed shortly by illness, with free urination, minimal thirst, and tender/painful areas in epigastrium, hypochondrium, or umbilical region (even untouchable), indicates Blood Stasis. Fatigue/labor, hunger/fullness, Seven Emotions, and sexual misconduct can all cause blood stasis, not just trauma. My friend Miao Zhongchun took multiple doses of tonic pills, suddenly developed persistent fever. Cooling/clearing herbs worsened his condition, leading to extreme exhaustion. I treated him using the Blood Stasis method. While decocting, he smelled the aroma and drank it; fever subsided. Next day, he passed a bucket of black stool and recovered. Shaoyang disease has its own Blood Stasis syndrome, which should be sought within the Shaoyang discipline. This passage discusses miscellaneous diseases involving blood stasis that resemble Shaoyang disease.