丹毒者。为肌表忽然变赤如丹涂之状也。经曰。少阴司天。客胜则丹疹外发。及为丹 。然二症亦有红
白干湿痒痛之殊。故用药则分表里补泻之异。如色赤而干。发热作痛者。为丹毒。属肝心之火。宜化斑
解毒汤。色白而湿烂。流黄水。痒痛不时者。为风丹。属脾肺湿热。宜除湿胃苓汤。痒而搔之起块。成饼成
片。皮色不变者。为冷膜。故天阴则剧。风中亦剧。晴暖则减。身暖则瘥。由风邪外袭。热郁于肌肤也。宜藿
香正气散发之。外以枳壳煎汤浴之。忌用风药。
再如丹毒。由胃气虚极致令虚火游行于外者。又宜补以降之。用人参五钱。当归、白术各一钱五分。水
煎服之。
又如女子十五岁而经脉未通者。多发丹疹。此由血有风热乘之也。治宜凉血。虚则补之。慎投风药。
化斑解毒汤 治二焦风热上攻。致生火丹。延及遍身而作痒痛。
玄参 知母 石膏 黄连 牛蒡子 人中黄 升麻
连翘（各一钱） 甘草（五分）
水二钟。淡竹叶二十片。煎八分服。
除湿胃苓汤 治脾肺湿热。致生火丹。作烂疼痛者。
防风 苍术 白术 赤茯苓 陈皮 浓朴 猪苓 栀子 木通 泽泻 滑石（各一钱） 薄桂
甘草（各三分）
水二钟。灯心二十根。煎八分服。
藿香正气散 治冷膜。由风寒外袭者。
藿香 白术 白芷 桔梗 紫苏 陈皮 半夏 大腹皮 茯苓 浓朴 甘草
水二钟。生姜三片。红枣二个。煎八分服。
芸薹菜方 治丹毒。
芸薹菜子一两。黄酒一钟。和研。滤去渣。煎四五沸。温服之。
一杵芸薹菜叶敷之。干者为末。水调敷之。
柏叶散 治丹毒痒痛。并效。
侧柏（炒黄） 黄柏 大黄（各五钱） 赤豆（三钱） 蚯蚓粪（韭菜田内者佳，五钱） 轻粉（三钱）
为末。新汲水调敷。
一捣大蒜浓涂之。干则易之。
Dan Du (Erysipelas) refers to the sudden appearance of redness on the skin surface, resembling a coating of cinnabar. The *Classic of Internal Medicine* states: "When Shaoyin governs the year, if the pathogenic qi prevails, Dan Zhen (erythematous rashes) will erupt externally, forming Dan Chuang (erysipelas sores)." However, these two conditions differ in terms of redness or whiteness, dryness or dampness, and itching or pain. Therefore, medication must distinguish between exterior/interior patterns and tonification/draining methods. If the color is crimson and dry, accompanied by fever and pain, it is termed Dan Du (Erysipelas), belonging to the fire of the Liver and Heart. It is suitable for Hua Ban Jie Du Tang (Spot-Resolving Toxin-Expelling Decoction). If the color is white and moist with erosion, oozing yellow fluid, accompanied by intermittent itching and pain, it is termed Feng Dan (Wind Erysipelas), belonging to Damp-Heat of the Spleen and Lung. It is suitable for Chu Shi Wei Ling Tang (Dampness-Removing Weiling Decoction). If there is itching, and scratching causes raised plaques forming cake-like or patchy lesions without changing the skin color, it is termed Leng Mo (Cold Membrane, a type of dermatitis caused by wind-cold-dampness). Thus, the condition worsens on cloudy days or when exposed to wind, and improves on warm sunny days or when the body is warm. This is caused by external invasion of Wind Pathogen with heat stagnating in the muscle layer. It is suitable for Huo Xiang Zheng Qi San (Patchouli Powder for Regulating Qi) to release the exterior, and bathing externally with decoction of Zhike (Aurantii Fructus). Wind-dispelling herbs should be avoided.
Furthermore, regarding Dan Du (Erysipelas), if it is caused by extreme deficiency of Stomach Qi leading to Deficient Fire wandering externally, one should use tonification to guide the fire back. Use Renshen (Ginseng Radix et Rhizoma) 5 qian, Danggui (Angelicae Sinensis Radix) and Baizhu (Atractylodis Macrocephalae Rhizoma) each 1.5 qian, decocted in water and taken orally.
Moreover, in women aged fifteen whose menstruation has not yet commenced, Dan Zhen (erythematous rashes) often occur frequently. This is due to Wind-Heat attacking the Blood level. Treatment should focus on Cooling Blood; if deficiency exists, Tonify. Be cautious with Wind-dispelling herbs.
Hua Ban Jie Du Tang (Spot-Resolving Toxin-Expelling Decoction): Treats Wind-Heat attacking upward from the Upper and Middle Jiao, causing Huo Dan (Fire Erysipelas), spreading over the whole body with itching and pain.
Xuan Shen (Scrophulariae Radix), Zhi Mu (Anemarrhenae Rhizoma), Shigao (Gypsum Fibrosum), Huanglian (Coptidis Rhizoma), Niubangzi (Arctii Fructus), Renzhonghuang (Human Calculus), Shengma (Cimicifugae Rhizoma), Lianqiao (Forsythiae Fructus) (each 1 qian); Gancao (Licorice Root) (0.5 qian).
Use 2 zhong of water, 20 leaves of Dan Zhuye (Lophatheri Herba), decoct until 0.8 zhong remains, then take orally.
Chu Shi Wei Ling Tang (Dampness-Removing Weiling Decoction): Treats Damp-Heat of the Spleen and Lung, causing Huo Dan (Fire Erysipelas) with erosion and pain.
Fangfeng (Saposhnikoviae Radix), Cangzhu (Atractylodis Rhizoma), Baizhu (Atractylodis Macrocephalae Rhizoma), Chi Fuling (Poria with Red Core), Chenpi (Citri Reticulatae Pericarpium), Nong Po (Magnoliae Officinalis Cortex), Zhuling (Polyporus), Zhizi (Gardeniae Fructus), Mutong (Akebiae Caulis), Zexie (Alismatis Rhizoma), Huashi (Talcum) (each 1 qian); Bo Gui (Cinnamomi Cortex) and Gancao (Licorice Root) (each 0.3 qian).
Use 2 zhong of water, 20 roots of Dengxin (Junci Medullia), decoct until 0.8 zhong remains, then take orally.
Huo Xiang Zheng Qi San (Patchouli Powder for Regulating Qi): Treats Leng Mo (Cold Membrane) caused by external invasion of Wind-Cold.
Huo Xiang (Agastaches Herba), Baizhu (Atractylodis Macrocephalae Rhizoma), Baizhi (Angelicae Dahuricae Radix), Jiegeng (Platycodonis Radix), Zisu (Perillae Folium), Chenpi (Citri Reticulatae Pericarpium), Banxia (Pinelliae Tuber), Dafupi (Arecae Pericarpium), Fuling (Poria), Nong Po (Magnoliae Officinalis Cortex), Gancao (Licorice Root).
Use 2 zhong of water, 3 slices of Shengjiang (Zingiberis Rhizoma Recens), 2 Hongzao (Jujubae Fructus), decoct until 0.8 zhong remains, then take orally.
Yuntai Cai Fang (Rapeseed Vegetable Prescription): Treats Dan Du (Erysipelas).
Yuntai Caizi (Brassicae Napus Seed) 1 liang, Huangjiu (Yellow Wine) 1 zhong. Mix and grind, filter out dregs, boil for four or five boils, and take warm.
Alternatively, crush fresh Yuntai Caiye (Rapeseed Leaves) and apply topically. If dried, grind into powder, mix with water, and apply topically.
Bai Ye San (Cypress Leaf Powder): Treats itching and pain of Dan Du (Erysipelas), effective.
Ce Baiye (Biota Tops) (stir-fried until yellow), Huangbai (Phellodendri Cortex), Dahuang (Rhei Radix et Rhizoma) (each 5 qian); Chidou (Vigna Angularis Semen Rubrum) (3 qian), Qiuyin Fen (Earthworm Excrement) (preferably from leek fields, 5 qian), Qingfen (Calomel) (3 qian).
Grind into fine powder, mix with fresh drawn water, and apply topically.
Alternatively, crush fresh Dasuan (Garlic Bulb), apply thickly to the affected area, and replace when dry.