《心法》曰∶四弯风，生于两腿弯及两脚拗，每月一发，形如风癣，乃风邪袭入
腠理而成。其痒无度，搔破津水形如湿癣，治当大麦一升熬汤，先熏后洗，搽三妙散
渗湿杀虫之药，其痒自止，缓缓取效。（《金鉴》）
凡腿上或头面红赤肿热，流散无定，以碱水扫上旋起白霜者，此流火也。 流火
两脚红肿光亮，其热如火者是。
骆潜庵曰∶腿脚红肿名火延丹。
贴骨火 天茄子捣烂，醋调敷之。
诸般火。
黄柏 草乌（各等分）
研细末，用水口中漱过吐出调药，鹅毛扫数次。
脚下火 煤炭研细，陈醋调敷。
流火（《卫生备要》）。野辣芥子五钱，研细醋调敷。
脚上流火 广煤用红糖醋磨敷。
流火。
当归 生地 防己 川牛膝 知母（各三钱）
生姜汁半杯，水煎。临晚服，服后再吃晚饭。不可过饱，一剂自好。
流火。
苏薄荷 黄柏 猪苓 赤芍 木瓜 甘草 陈皮 川芎 苍术 川牛膝 羌活 薏苡仁 天花粉
葱姜引服一二剂，加当归、泽泻、木通，引换姜枣自愈。
敷流火。
雄黄 百草霜 食盐（各等分） 蚯蚓粪块煤炭（加倍） 醋调敷。
流火 马前子水磨浓汁，鸡翎扫红肿上，一日五七次，其疼即止，红自退，两三日肿全消。
流火腿脚通红 用炭三斤烧红，以水一盆，将红炭淬入水内，其水必热，将红处洗之，即消。
流火香港脚 取活大蛤蟆肚子合足底，以绢帛缚好，看蛤蟆眼睛红即解下放去，另换一个再缚之，自愈。
火延丹 白海蜇皮洗净拭干，包扎肿处一伏时，揭开看，如蜇皮黄枯，即另
换一张包裹，如此者三四张，即能消散矣。
《医宗心法》说：四弯风，生长在两条腿的腘窝（膝盖后方凹陷处）以及双脚脚踝弯曲处，每月发作一次，形态像风癣，这是风邪侵入腠理（皮肤纹理及皮下组织间隙）所致。其瘙痒程度无度，抓破后渗出津液，形态如同湿癣，治疗应当用大麦一升熬汤，先熏蒸后清洗，再涂抹三妙散等具有渗湿杀虫功效的药物，瘙痒自然停止，缓缓见效。（出自《医宗金鉴》）
凡是腿部或头面部出现红赤肿胀发热，红肿部位流动扩散没有固定位置，用碱水擦拭后随即泛起白霜的，这就是流火。流火表现为双脚红肿光亮，热度如火烧的是典型症状。
各种火症：
黄柏、草乌（各取等量）
研成细末，用水漱口后吐出，以此唾液调制药粉，用鹅毛刷涂抹数次。
流火（出自《卫生备要》）：野辣芥子五钱，研细后用醋调和敷贴。
流火：
当归、生地、防己、川牛膝、知母（各三钱）
加入半杯生姜汁，加水煎煮。傍晚服用，服药后再吃晚饭。不可吃得过饱，服用一剂即可痊愈。
流火：
苏薄荷、黄柏、猪苓、赤芍、木瓜、甘草、陈皮、川芎、苍术、川牛膝、羌活、薏苡仁、天花粉
以葱、姜为引服用一二剂，之后加入当归、泽泻、木通，以姜枣为引，自愈。
外敷治疗流火：
雄黄、百草霜、食盐（各取等量）、蚯蚓粪块、煤炭（用量加倍）
用醋调和敷贴。
流火：马前子用水磨成浓汁，用鸡毛扫帚蘸取涂抹在红肿处，一天五到七次，疼痛立即停止，红色自然消退，两三天后肿胀完全消除。
流火腿脚通红：用炭三斤烧红，准备一盆水，将烧红的炭淬入水中，水必热，用此热水洗涤红肿部位，即刻消散。
流火合并香港脚（足癣/脚气）：取活的大蛤蟆，将其腹部贴合于脚底，用绢帛绑好，观察蛤蟆的眼睛变红时解开并放走，再换一只新的绑上，如此自愈。
火延丹：将白海蜇皮洗净擦干，包扎在肿胀处一个时辰（两小时），揭开查看，如果海蜇皮变黄干枯，就另换一张包裹，如此更换三四张，肿胀就能消散了。
*Yizong Xinfa* states: Siwan Feng (Four-Bend Wind), occurs in the popliteal fossae of both legs and the ankle joints, manifesting once a month. Its appearance resembles wind xanthoma (a type of itchy skin lesion resembling tinea). It is caused by wind pathogen invading the couli (the interstitial spaces between skin and muscles). The itching is extreme; scratching breaks the skin, exuding fluid, resembling damp xanthoma. Treatment should involve boiling one sheng of barley to make a decoction, first fumigating and then washing the area, followed by applying Sanmiao Powder or other herbs with properties of draining dampness and killing parasites. The itching will cease naturally, and efficacy will be achieved gradually. (From *Yizong Jinjian*)
Whenever the legs or head and face present with redness, swelling, heat, and inflammation that spreads without a fixed location, and white frost appears immediately after wiping with alkali water, this is called Liuhuo (Flowing Fire). Typical Liuhuo presents as bright red and swollen feet with intense heat like fire.
Luo Qian'an stated: Redness and swelling of the legs and feet are named Huoyan Dan (Fire Spreading Cinnabar).
Tiegou Huo (Bone-Adhering Fire): Mash Tianqiezi (Solanum surattense) into a paste, mix with vinegar, and apply topically.
Various types of "Fire":
Huangbai (Phellodendri Cortex) and Caowu (Aconiti Radix) in equal parts.
Grind into fine powder. Rinse mouth with water and spit out saliva to mix with the medicine. Apply several times using a goose feather brush.
Jiaoxia Huo (Foot-Bottom Fire): Grind coal into fine powder, mix with aged vinegar, and apply topically.
Liuhuo (From *Weisheng Beiyao*): Use five qian of Yelajiezi (Wild Mustard Seed), grind into fine powder, mix with vinegar, and apply topically.
Jiaoshang Liuhuo (Liuhuo on Feet): Use Guangmei (high-quality bituminous coal), grind with brown sugar and vinegar, and apply topically.
Liuhuo:
Danggui (Angelicae Sinensis Radix), Shengdi (Rehmanniae Radix), Fangji (Stephaniae Tetrandrae Radix), Chuan Niuxi (Achyranthis Bidentatae Radix), Zhiimu (Anemarrhenae Rhizoma) — each three qian.
Add half a cup of fresh ginger juice, decoct with water. Take in the evening, followed by dinner. Do not overeat. One dose will result in recovery.
Liuhuo:
Subohemp (Menthae Haplocalycis Herba), Huangbai (Phellodendri Cortex), Zhuling (Polyporus), Chishao (Paeoniae Radix Rubra), Mugua (Chaenomelis Fructus), Gancao (Glycyrrhizae Radix et Rhizoma), Chenpi (Citri Reticulatae Pericarpium), Chuanxiong (Chuanxiong Rhizoma), Cangzhu (Atractylodis Rhizoma), Chuan Niuxi (Achyranthis Bidentatae Radix), Qianghuo (Notopterygii Rhizoma et Radix), Yiyiren (Coicis Semen), Tianhuafen (Trichosanthis Radix).
Take one or two doses with green onion and ginger as guides. Subsequently add Danggui (Angelicae Sinensis Radix), Zexie (Alismatis Rhizoma), Mutong (Akebiae Caulis), guided by ginger and jujube, for spontaneous recovery.
Topical application for Liuhuo:
Xionghuang (Realgar), Baicaoshuang (Soot from Chimney), Shiyen (Halitum) in equal parts; Earthworm feces and coal in double quantity. Mix with vinegar and apply topically.
Liuhuo: Grind Qianjizi (Strychni Semen) in water to make a thick juice. Apply to the red and swollen area with a chicken feather brush five to seven times a day. Pain stops immediately, redness fades, and swelling subsides completely within two to three days.
Liuhuo with red-hot legs and feet: Burn three jin of charcoal until red-hot. Prepare a basin of water and quench the hot charcoal into it. The water will become hot. Wash the affected red areas with this hot water, and the condition will dissipate immediately.
Liuhuo combined with Hongkong Foot (Tinea Pedis): Take a live large toad, press its belly against the sole of the foot, and bind securely with silk cloth. Observe the toad's eyes; when they turn red, untie and release it. Replace with another toad and bind again. This leads to spontaneous recovery.
Huoyan Dan: Clean and dry the skin of Bai Haizhe (Cystoseira Tamariscifolia / White Sea Jellyfish). Bandage the swollen area for one fushi (two hours). Upon removal, if the jellyfish skin turns yellow and dry, replace it with a new piece. Repeat this process three or four times, and the swelling will dissipate.