（附手足汗 盗汗）
凡阳明病一身自汗出者。谓之热越。此热从外达也。若热不得越而从上达。则有头汗证
。从
傍达则有手足汗证。而其证皆属阳而不属阴。仲景云。阴不得有汗。故以是列阳明证也。
头为诸阳之会。邪郁于里。不得外越。热蒸于阳。则头汗自出。凡见此证者。
多发黄。经云。但头汗出。余处无汗。剂颈而还。身必发黄。又云。阳明病被火。额上
微汗出。而小便不利者。必发黄。此以热郁在里。不得外越故也。然其间有郁之浅者。如经云。阳明
病
下之。其外有热。手足温。不结胸。心中懊 。饥不能食。但头汗出者。栀子豉汤主之。此
可用吐法以宣其热也。有郁之深者。如经云。伤寒热结在里。但结胸无大热者。此为水结在
胸胁也。但头微汗出者。大陷胸汤主之。此可用下法以泄其热也。此皆阳明病。其邪不能外
出于阳明之表。而郁在阳明之里也。
其有不属阳明而属少阳者。经云。伤寒五六日。头汗出微恶寒。手足冷。心下满。口不
欲食
。大便硬。脉细者。此为阳微结。必有表复有里也。脉沉亦在里也。汗出为阳微。假令纯阴
结
。不得复有外证。悉入在里。此为半在里半在外也。脉虽沉紧。不得为少阴病。所以然者。
阴不得有汗。今头汗出。故知非少阴也。可与小柴胡汤。设不了了者。得屎而解。又云。伤
寒
五六日。已发汗而复下之。胸胁满微结。小便不利。渴而不呕。但头汗出。往来寒热心烦者
。此为未解也。柴胡桂枝干姜汤主之。小柴胡本少阳之剂。所以两和表里。今里证已具。而
犹持于半表。故尚见头汗证也。
更有邪热陷里而成头汗证者。经曰。阳明病下血谵语者。此为热入血室。但头汗出者。
刺期门
。随其实而泄之。 然汗出而愈。盖热入血室而肝藏实。故当刺肝之期门以泄其实。血液为
汗。热邪并汗而出。则血自止矣。然此犹入里之浅者也。更有太阳中风。以火劫发汗。阴阳
俱虚竭。身体则枯燥。但头汗出。剂颈而还。此则津液垂涸之证。惟小便利者。则一线真阴
未涸。可以亟救其真阴。故虽种种危证悉具。而仲景曰。小便利者。其人可治也。
又有真阳上脱而头汗者。经云。关格不通。不得尿。头无汗者生。有汗者死。又云。湿
家下之其人额上汗出。微喘者死。此绝证不可治也。
手足汗乃专属阳明证。经云。手足 然汗出者。此大便已硬也。手足 汗出。大便难
而谵
语者。下之则愈。盖阳明属胃。胃主四肢。此由热聚于胃也。然又有不属热而属寒者。经云
。阳明病不能食。小便不利。手足 然汗出。此欲作固瘕。必大便初硬后溏。所以然者。以
胃中冷。水谷不别故也。热聚于胃者。可下。寒聚于胃者。不可下。此又不可不辨也。
更有盗汗者。乃半表半里证。邪气侵行于里。外连于表。睡则卫气行于里。乘表中阳气
不致
。津液得泄。故但睡而汗出。觉则气散于表而汗止矣。故经云。微盗汗出反恶寒者。表未解
也。又阳明病当作里实而脉浮者。云必盗汗。又三阳合病。目合则汗。凡若此者。皆当清里
和表为治。盖伤寒盗汗。与杂病之盗汗不同。杂病盗汗可用补法。伤寒盗汗则惟有和表而已
。无补法也。
(Attached: Sweating of Hands and Feet, Night Sweats)
When a patient with Yangming disease presents with spontaneous sweating over the entire body, it is termed "Heat Venting" (Re Yue). This indicates that heat is dispersing outward from the exterior. If heat cannot vent outward but instead steams upward, a syndrome of head sweating occurs. If heat disperses laterally, sweating of the hands and feet occurs. These syndromes all belong to Yang and not to Yin. Zhang Zhongjing stated, "Yin syndromes do not present with sweating," hence these are listed under Yangming disease patterns.
The head is the confluence of all Yang meridians. When pathogenic factors are constrained internally and cannot vent outward, heat steams into the Yang regions, resulting in spontaneous head sweating. Whenever this symptom appears, jaundice often develops. The Classics state: "Sweating only on the head, with no sweat elsewhere on the body, stopping at the neck, inevitably leads to jaundice." It also states: "In Yangming disease, if fire therapy is applied and there is slight sweating on the forehead accompanied by difficulty in urination, jaundice will inevitably develop." This is because heat is constrained internally and cannot vent outward. However, among these cases, some involve shallow constraint. As the Classics state: "After purgation in Yangming disease, if there is residual heat on the exterior, warm hands and feet, no formation of Jie Xiong (Chest Binding), mental restlessness and oppression (Ao Nu), hunger but inability to eat, and only head sweating, Zhi Zi Chi Tang (Gardenia and Fermented Soybean Decoction) should be administered." In such cases, emesis can be used to ventilate the heat. There are also cases of deep constraint. As the Classics state: "In Shang Han (Cold Damage), when heat is constrained internally but without significant heat in Jie Xiong, this indicates water retention in the chest and hypochondrium. With only slight head sweating, Da Xian Xiong Tang (Major Downward Draining Chest Decoction) should be administered." Here, purgation can be used to drain the heat. All these are Yangming diseases where the pathogen cannot vent to the exterior of the Yangming channel but remains constrained in the interior of Yangming.
There are cases that do not belong to Yangming but to Shaoyang. The Classics state: "After five or six days of Shang Han, with head sweating, slight aversion to cold, cold hands and feet, fullness in the epigastrium, desire not to eat, hard stools, and a fine pulse, this is called 'Yang Micro-Constraint' (Yang Wei Jie). There is both an exterior and an interior aspect. A deep pulse indicates the interior. Sweating indicates mild Yang deficiency. If it were a pure Yin constraint, there would be no exterior signs remaining; everything would have entered the interior. This is half-exterior and half-interior. Although the pulse may be deep and tight, it cannot be diagnosed as a Shaoyin disease. The reason is that Yin syndromes do not present with sweating. Since there is head sweating now, we know it is not Shaoyin. Xiao Chai Hu Tang (Minor Bupleurum Decoction) may be given. If the patient still feels unwell after administration, resolution will occur upon defecation." It also states: "After five or six days of Shang Han, if sweating was previously induced and then purgation was performed again, resulting in fullness and slight binding in the chest and hypochondrium, difficulty in urination, thirst without vomiting, only head sweating, alternating chills and fever, and irritability, the disease has not yet resolved. Chai Hu Gui Zhi Gan Jiang Tang (Bupleurum, Cinnamon Twig, and Dried Ginger Decoction) should be administered." Xiao Chai Hu Tang is originally a formula for Shaoyang disease, used to harmonize the exterior and interior. Now that interior signs are fully present, yet the pathogen still lingers at the semi-exterior level, head sweating persists.
Furthermore, there are cases where pathogenic heat sinks into the interior causing head sweating. The Classics say: "In Yangming disease, if bleeding from the rectum and delirium occur, this is Heat Entering the Blood Chamber (Re Ru Xue Shi). With only head sweating, puncture Qi Men (LR14). Discharge the excess according to its reality. Recovery follows when natural sweating occurs." This is because heat entering the Blood Chamber causes Liver excess, so puncturing Qi Men, the Front-Mu point of the Liver, discharges the excess. Blood transforms into sweat; as heat exits with the sweat, abnormal bleeding ceases. However, this represents a relatively shallow penetration into the interior. There are also cases of Taiyang Wind Strike treated with fire-induced sweating, leading to exhaustion of both Yin and Yang, dryness and roughness of the body, and only head sweating stopping at the neck. This is a syndrome of impending fluid depletion. Only if urination is free does it indicate that a thread of True Yin remains intact, allowing for urgent rescue of True Yin. Thus, although various critical signs are present, Zhang Zhongjing states: "If urination is free, the patient is treatable."
There are also cases of head sweating due to the floating away of True Yang. The Classics state: "When Guan Ge (Obstruction and Repletion) prevents urination, survival is indicated if there is no head sweating; death is indicated if there is head sweating." It also states: "In patients with Dampness, if purgation is incorrectly applied, resulting in sweating on the forehead and slight panting, death ensues." This is a terminal syndrome that is untreatable.
Sweating of the hands and feet specifically belongs to Yangming disease. The Classics state: "Profuse sweating of the hands and feet indicates that the stool has become hard. If profuse sweating of the hands and feet is accompanied by difficult defecation and delirium, purgation will lead to recovery." This is because Yangming corresponds to the Stomach, and the Stomach governs the four limbs. This results from heat accumulating in the Stomach. However, there are cases not caused by heat but by cold. The Classics state: "In Yangming disease, if the patient cannot eat, urination is difficult, and there is profuse sweating of the hands and feet, this suggests the impending formation of Gu Jia (Solid Mass). The stool will likely be hard initially and loose later. This is because of cold in the Stomach, failing to separate water and grain." Cases with heat accumulation in the Stomach can be purged; cases with cold accumulation in the Stomach must not be purged. This distinction must not be overlooked.
Regarding night sweats (Dao Han), they belong to the semi-exterior, semi-interior stage. Pathogenic factors invade and circulate in the interior while connecting externally to the exterior. During sleep, Wei Qi (Defensive Qi) moves inward. Lacking the anchoring power of Yang Qi in the exterior-interior interface, body fluids leak out, causing sweating only during sleep. Upon waking, Qi disperses to the exterior, and sweating stops. Thus, the Classics state: "Slight night sweating with contrary aversion to cold indicates the exterior pattern has not resolved." It also states: "In Yangming disease, which should be an interior excess pattern, if the pulse is floating, night sweating is inevitable." Furthermore, "In combined disease of the Three Yang, sweating occurs when the eyes are closed." In all such cases, clearing the interior and harmonizing the exterior should be the treatment principle. Note that night sweating in Shang Han differs from that in miscellaneous diseases. Night sweating in miscellaneous diseases can be treated with tonification, whereas in Shang Han, only harmonizing the exterior is applicable; tonification is not used.