经义
跛，风寒湿之病也。○清湿袭虚，则病起于下。（《素问》）
脾有邪，其气流于两股；肾有邪，其气流于两 。（《灵枢》）
哲言
香港脚自外感得者，山岚雨水或履蹈湿热之地；自内伤得者，生冷茶酒及油面湿热之毒。湿性下流，故注于
足。湿热交争，湿胜则憎寒，热胜则壮热。有兼头痛诸证，状类伤寒，但胫肿掣痛为异耳。此病忌用补剂及淋
洗，以湿热得补增剧也。若香港脚冲心，喘息不止，呕吐不休者，死。（《医方集解》）
经曰∶诸湿肿满，皆属于脾。又曰∶伤于湿者，下先受之。盖脾主四肢，足居于下，而多受湿，湿郁成热，
湿热相搏，其痛作矣。古无香港脚之说，《内经》名厥，两汉间名缓风，宋齐后始谓之香港脚。有从外感而得者，
有从内伤而致者，其为湿热之患则一。北方高燥，多饮HT 酪及醇酒，湿热之物下流足胫所致。
南方卑下，湿气弥满山泽，血气虚弱之人，或遇房劳，及负重远行，冲冒雨雪，寒湿乘虚而袭，遂成此证。大
抵风、寒、暑、湿之气，中于诸阳病在外；中于诸阴病在内。自汗走注为风胜；无汗疼痛挛急为寒胜；肿满重
着为湿胜；烦渴热顽为暑胜。寒则温之，热则寒之，在表则散之，在里则下之。若大虚气乏，间作补汤，随病冷
热而用之，勿执不得服补药之说。（《赤水玄珠》）
香港脚之说，古所无也，自晋苏敬始有此名。然其肿痛麻顽，即《经》之所谓痹也。其纵缓不收，即《经》
之所谓痿也。其甚而上冲，即《经》之所谓厥逆也。○香港脚之证，其初甚微，饮食动作如故，或无他疾而忽得之，
或因病后而渐得之。及其病也，则自膝至足，或见麻痹冷痛，或见痿弱挛急，或肿或不肿，或日渐枯细，或发
热恶寒，或如冰冷，或如火热，或能食，或不能食，或有物如指，发自 腓，而气上冲心，是皆香港脚之正病也。
其有为头痛寒热，或腹痛呕吐，或不欲见明，或错语昏愦，是皆香港脚之兼证也。大抵证有缓急，缓者其来渐，
急者其来速。治之若缓，气上冲心，亦能杀人。○观《活人书》云∶凡香港脚服补药，及用汤淋洗者，皆所禁也。
此亦一偏之说耳。盖补有宜禁者，以邪壅气实者也；淋洗有宜禁者，以水湿汤气之宜避者也。如果下部虚寒，
或以病后，或以克伐太过，而香港脚不愈者，岂尚堪禁补乎？又若寒邪、湿热壅结不散，而为肿、为痛者，最宜
辛香疏散之药，煎汤蒸洗，则退邪极速，岂禁洗乎？惟是湿热气逆而上冲心腹者，不可骤洗，恐助升也。此必
先降其气，俟其毒止在脚，再行熏洗，自无不利。盖补以补其弱，洗以逐其滞，夫何禁之有？（张景岳）
问曰∶湿毒中人，何偏着于足？答曰∶人之五脏，心、肺二脏经络起于手十指；肝、肾、脾三脏经络起
于足十趾。湿毒之气，皆起于地，足常履之，所以中人必先中足。微时不觉，痼滞方知，○凡香港脚，不得一概
以肿为候。有肿者，有不肿者。其有少腹顽痹不仁，脚多不肿，三、五日后令人呕吐，名香港脚冲心。死在旦
夕，肾水克心火故也。○凡香港脚，其人瘦者易治，肥者难治。瘦人肉硬，肥人肉软。肉软则受疾深，故难治。
○凡香港脚之疾，多由气实而死，鲜由气虚而殂，不可大补，不可大泻。亦不得畏虚，止汤不服也。（《千金方》）
香港脚之疾，自古皆尚疏利，为壅疾故也。然不可太过，太过则损伤脾胃；又不可不及，不及则使壅滞不消。（李东垣）
湿香港脚者，筋脉弛而浮肿，或但肿而不上升，此属湿胜，宜利湿疏风。干香港脚者，筋脉蜷缩，枯细不肿，
因他病而发，有时上冲，此属热胜，宜凉血清火。（《证治汇补》）
凡湿热之气，升则化，不升则壅。故上实下虚者有香港脚，湿从寒受也；上虚下实者尤有香港脚，热自湿上也。
所以然者，湿为浊邪，中下更遭土淫，陷入郁住三焦之火，交蒸成壅也。法当坚土清火，降处行升，使清阳出
上窍，浊阴出下窍，厘清之法，莫善于此。（程郊清）
香港脚多由伤湿，湿郁成热，湿热相搏，而后作也，名为壅疾。治当宣通，如羌活导滞汤、当归拈痛汤之类。
而证之虚、实、寒、热、表、里、轻、重，又当分别。黄柏、苍术乃湿热必用之药；防己能治腰下湿热肿盛；
木瓜能治香港脚湿痹，入肝舒筋；苦参除湿兼去风热；黄芩凉血兼去湿热；白术、赤茯、猪苓、泽泻、肉桂、茵
陈、木通俱渗利湿热。湿兼风者，则用防风、羌、独、白芷、细辛；湿兼寒者，则用乌、附、肉桂。考之是疾，
多是气不流行，有所滞而作，须用木香、槟榔、枳壳、香附、乌药顺行气道。气虚兼用参、 、白术以益其气；
血虚兼用归、芍、川芎、熟地以养其血；血凝用桃仁、红花；消肿用腹皮、桑皮、乳香、没药；壮筋骨用牛膝、
杜仲、萆 、虎胫。是知香港脚之治，惟散风清热，调血行气，利关节，消肿满为要也。（《医宗粹言》）
足少阴香港脚入腹疼痛，上气喘促欲死，惟八味丸最佳。阳衰肾虚有寒之人，多患此证，乃肾乘心、水克
火也。（《医学六要》）
脉候
脉浮弦起于风，濡弱起于湿，洪数起于热，迟涩起于寒。沉而伏，毒在筋骨也；指下涩滞不调，毒在血分
也。夏暑脚膝冷痛，其脉阳濡阴弱者，湿温也。（《张氏医通》）
选案
有人病足不履地者十年，医莫能治。遇一游僧曰∶此疾一药可愈。因为入山求得，威灵仙也。使服数日即
能步履。（《赤水玄珠》）
一妇患腿痛不能伸屈，遇风寒痛益甚，诸药不应。以活络丹一丸服之顿减，再服而瘳。次年复病，仍服一
丸即减大半，更服独活寄生汤而愈。○一男子素有香港脚，又患附骨疽作痛，服活络丹一丸，二证并瘥。○上舍
俞鲁用素有疝疾。因患腿痛，服活络丹一丸，不惟腿患有效，而疝疾亦愈。夫病邪深伏于内，非此药莫能通达。
俗云此药引风入骨，如油入面，以致人不敢服。大抵有此病，服此药，岂可泥于俗说。（《薛氏医案》）
附方
杉木汤 柳子浓救死方云∶夜半得香港脚痛绝，腹块如石，昏困且死，此汤服之大下，块散气通。方用杉
木一节、橘叶一升（无叶以皮代之）、大腹槟榔七枚（连子捶碎）、童便三升，煮，分二服。若一服得快利，
即停后服。
五枝汤洗方 足上红肿疼痛者，为湿香港脚。不肿者，为干香港脚。麻木者，为风。此方均治。柳枝、桃枝、
楮枝、桑枝、槐枝各等分，水煎洗。
[Classic Discourses]
Limping is a disease caused by wind, cold, and dampness. ○ When clear and cold dampness invades the deficient parts of the body, diseases arise in the lower part. (Suwen)
When pathogenic factors reside in the Spleen, their qi flows into the two thighs; when pathogenic factors reside in the Kidney, their qi flows into the two calves. (Lingshu)
[Philosophical Remarks]
Hong Kong Foot (Jiaoxi / Beriberi) acquired from external contraction is often due to mountain miasma and rainwater or treading on damp-heat places; that acquired from internal injury is due to the toxicity of cold/raw foods, tea, alcohol, and oily/noodle foods which generate damp-heat. Dampness has a downward nature, so it pours into the feet. When dampness and heat contend, excess dampness causes aversion to cold, while excess heat causes high fever. Some cases present with headache and other symptoms resembling Taiyang disease (Exterior Syndrome), but differ in that the shins are swollen and pulling painful. This disease contraindicates the use of tonifying agents and washing therapies, as damp-heat worsens with tonification. If Hong Kong Foot attacks the Heart, causing unceasing panting and incessant vomiting, death ensues. (Yifang Jijie)
The Classics state: All swelling and fullness due to dampness belong to the Spleen. It also states: Those injured by dampness receive it first in the lower part. Generally, the Spleen governs the four limbs; the feet are located inferiorly and are prone to dampness. Dampness stagnates and transforms into heat; when damp-heat contends, pain arises. In ancient times, there was no term "Hong Kong Foot"; the Neijing called it "Jue" (Reversal), during the Two Han Dynasties it was called "Huan Feng" (Sluggish Wind), and after the Song and Qi dynasties it was termed "Hong Kong Foot". It can be acquired from external contraction or internal injury, but both are disorders of damp-heat. The North is high and dry; people drink milk curds and strong wine, and these damp-heat substances flow down to the shins and feet.
The South is low and wet; dampness fills the mountains and marshes. People with weak qi and blood, or those who engage in sexual fatigue, carry heavy loads over long distances, or expose themselves to rain and snow, allow cold-dampness to invade through deficiency, thus forming this syndrome. Generally, wind, cold, summer-heat, and dampness invading the Yang meridians result in exterior diseases; invading the Yin meridians results in interior diseases. Spontaneous sweating and wandering pain indicate excess wind; absence of sweating, pain, and spasmodic tightness indicate excess cold; swelling, fullness, and heaviness indicate excess dampness; irritability, thirst, and stiff heat indicate excess summer-heat. Cold is treated with warming methods; heat with cooling methods; exterior diseases with dispersing methods; interior diseases with purging methods. If there is severe deficiency and lack of qi, intermittent use of tonifying decoctions should be employed according to the cold or heat of the disease, without rigidly adhering to the notion that tonics must not be taken. (Chishui Xuanzhu)
The term "Hong Kong Foot" did not exist in antiquity; it originated with Su Jing of the Jin Dynasty. However, its swelling, pain, numbness, and stiffness correspond to the "Bi Syndrome" described in the Classics. Its flaccidity and inability to contract correspond to the "Wei Syndrome" (Flaccidity Syndrome). Its severity and upward counterflow correspond to the "Jue Ni" (Reversal Cold) described in the Classics. ○ The manifestations of Hong Kong Foot are initially subtle; diet and movement remain normal. It may appear suddenly without prior illness, or gradually after an illness. Once established, from the knees to the feet, one may see numbness and cold pain, or flaccidity and spasms, or swelling or no swelling, or gradual emaciation, or fever and aversion to cold, or sensations of ice-coldness or fire-heat, or ability or inability to eat. A mass like a finger may arise from the calf, with qi rushing up to the Heart. These are the primary symptoms of Hong Kong Foot. Accompanying symptoms include headache and alternating chills/fever, abdominal pain and vomiting, aversion to light, delirium, and confusion. These are secondary symptoms. Generally, syndromes have slow or rapid onset; slow onset develops gradually, rapid onset develops quickly. If treatment is delayed and qi rushes to the Heart, it can cause death. ○ The Huoren Shu states: For Hong Kong Foot, taking tonics and using hot water washes are contraindicated. This is a biased view. Tonification is contraindicated when pathogens are obstructing and qi is excessive; washing is contraindicated to avoid exposure to water-damp steam. However, if the lower part is deficient and cold, or if the condition persists post-illness or due to excessive purgation, should tonification still be forbidden? Furthermore, for swelling and pain caused by stagnant cold-damp or damp-heat, pungent-aromatic dispersing herbs decocted for steaming/washing remove pathogens rapidly; why forbid washing? Only when damp-heat qi rebels upward to the Heart and abdomen should sudden washing be avoided, lest it aid the ascending pathogen. One must first descend the qi, wait for the toxin to settle in the feet, then perform fumigation and washing, which will be beneficial. Tonification addresses weakness; washing removes stagnation. What is there to forbid? (Zhang Jingyue)
Q: Why does damp-toxin preferentially affect the feet? A: The meridians of the Heart and Lung originate at the ten fingers of the hands; the meridians of the Liver, Kidney, and Spleen originate at the ten toes of the feet. Damp-toxin arises from the ground; the feet constantly tread upon it. Thus, when attacking humans, it strikes the feet first. Initially unnoticed, it is recognized only when it becomes entrenched. ○ For all Hong Kong Foot, swelling should not be universally regarded as a sign. There are cases with swelling and cases without. If there is numbness and insensitivity in the lower abdomen, and the feet do not swell, followed by vomiting after three to five days, it is named "Hong Kong Foot Attacking the Heart." Death occurs within dawn and dusk because Kidney Water overcomes Heart Fire. ○ For Hong Kong Foot, thin patients are easier to treat, while obese patients are difficult. Thin patients have firm flesh; obese patients have soft flesh. Soft flesh indicates deep pathology, hence difficult to treat. ○ Most deaths from Hong Kong Foot are due to excess qi, rarely due to deficient qi. Do not strongly tonify, nor strongly purge. Do not fear deficiency to the point of refusing medicinal pills, accepting only decoctions. (Qianjin Fang)
Historically, Hong Kong Foot has been treated with draining and promoting methods because it is a disorder of obstruction. However, one must not overdo it, as this damages the Spleen and Stomach; nor underdo it, as this fails to resolve obstruction. (Li Dongyuan)
Wet Hong Kong Foot features flaccid tendons and vessels with edema, or swelling without upward progression; this belongs to excess dampness, suitable for draining dampness and dispersing wind. Dry Hong Kong Foot features curled tendons and vessels, emaciation without swelling, often arising from other illnesses with occasional upward counterflow; this belongs to excess heat, suitable for cooling blood and clearing fire. (Zhengzhi Huibu)
When damp-heat qi ascends, it transforms; when it does not ascend, it obstructs. Thus, upper excess and lower deficiency lead to Hong Kong Foot due to dampness receiving cold; upper deficiency and lower excess especially lead to Hong Kong Foot due to heat rising from dampness. This is because dampness is turbid evil; in the middle and lower jiao, it encounters excessive earth qi, sinking and stagnating in the fire of the Sanjiao, steaming together to form obstruction. The method should be to strengthen Earth and clear Fire, treating the lower to promote ascent, allowing Clear Yang to exit through the upper orifices and Turbid Yin to exit through the lower orifices. No method clarifies better than this. (Cheng Jiaoqing)
Hong Kong Foot mostly arises from dampness injury, where dampness stagnates and transforms into heat, contending to cause the disease, named "Obstruction Disease." Treatment should promote circulation, such as Qianghuo Daozhi Tang or Danggui Niantong Tang. However, the deficiency/excess, cold/heat, exterior/interior, and mild/severe nature of the syndrome must be distinguished. Huangbai and Cangzhu are essential for damp-heat; Fangji treats damp-heat swelling below the waist; Mugua treats Hong Kong Foot damp-bi, entering the Liver to relax tendons; Kushen drains dampness and dispels wind-heat; Huangqin cools blood and clears damp-heat; Baizhu, Chifu Ling, Zhuling, Zexie, Rougui, Ychen, and Mutong all drain damp-heat. For dampness combined with wind, use Fangfeng, Qianghuo, Duhuo, Baizhi, and Xixin; for dampness combined with cold, use Wutou, Fuzi, and Rougui. Examining this disease, it is mostly due to qi stagnation and obstruction; Muxiang, Binglang, Zhike, Xiangfu, and Wuyao are needed to smooth qi flow. For qi deficiency, add Renshen, [missing character, likely Huangqi], and Baizhu to benefit qi; for blood deficiency, add Danggui, Shaoyao, Chuanxiong, and Shudi to nourish blood; for blood stasis, use Taoren and Honghua; for reducing swelling, use Fupi, Sangp Bai, Ruxiang, and Moyao; for strengthening sinews and bones, use Niuxi, Duzhong, Bibi, and Hu Jing Gu. Thus, the treatment of Hong Kong Foot focuses on dispersing wind and clearing heat, regulating blood and moving qi, benefiting joints, and reducing swelling and fullness. (Yizong Cuiyan)
For Shaoyin Meridian Hong Kong Foot with abdominal pain and panting approaching death, Bawei Wan is best. People with yang decline, kidney deficiency, and cold often suffer this, representing Kidney Qi assaulting the Heart and Kidney Water overcoming Heart Fire. (Yixue Liuyao)
[Pulse Diagnosis]
Floating and wiry pulses arise from wind; soggy and weak pulses arise from dampness; surging and rapid pulses arise from heat; slow and choppy pulses arise from cold. Deep and hidden pulses indicate toxin in sinews and bones; choppy and irregular pulses under the fingers indicate toxin in the blood level. Cold pain in legs and knees during summer heat, with a soggy superficial pulse and weak deep pulse, indicates Damp-Warmth. (Zhangshi Yitong)
[Selected Cases]
A person suffered from inability to walk for ten years, untreatable by physicians. A wandering monk said: One herb can cure this. He went to the mountains and obtained Weilingxian. After several days of administration, the patient could walk. (Chishui Xuanzhu)
A woman suffered from leg pain preventing flexion and extension, worsening with wind and cold, unresponsive to various medicines. Taking one pill of Huoluo Dan reduced symptoms immediately; a second dose cured her. Relapse the next year; one pill reduced it by half, and subsequent administration of Duhuo Jisheng Tang cured her. ○ A man with chronic Hong Kong Foot developed osteomyelitis (Fugu Ju) pain; one pill of Huoluo Dan cured both conditions. ○ Yu Luyong, a scholar-official, had chronic hernia. Due to leg pain, he took one pill of Huoluo Dan; not only did the leg ailment improve, but the hernia also resolved. Pathogens deeply lodged internally cannot be penetrated except by this medicine. Folklore claims this drug draws wind into bones like oil into flour, deterring use. However, for those with this disease, how can one cling to vulgar sayings? (Xue Shi Yi An)
[Attached Formulas]
Shanmu Tang (Fir Wood Decoction): From Liu Zinong's Jiusi Fang: Midnight onset of excruciating Hong Kong Foot pain, abdominal mass hard as stone, coma and impending death. This decoction induces profuse stool, dissipating masses and unblocking qi. Formula: One section of Fir Wood (Shanmu), one sheng of Tangerine Leaves (Juye, substitute peel if leaves unavailable), seven Areca Nuts (Dafu Binglang, crushed with seeds), three sheng of Child's Urine (Tongbian). Boil, divide into two doses. If the first dose produces rapid evacuation, stop the second dose.
Wuzhi Tang Wash (Five Branches Decoction Wash): Redness, swelling, and pain on the feet indicate Wet Hong Kong Foot; absence of swelling indicates Dry Hong Kong Foot; numbness indicates Wind. This formula treats all. Equal parts of Willow Branch (Liuzhi), Peach Branch (Taozhi), Paper Mulberry Branch (Chuzhi), Mulberry Branch (Sangzhi), and Locust Branch (Huai zhi). Decoct in water and wash.