痘疳，乃痘后余毒未尽，正气已亏，邪走空窍，是以口、鼻、眼、耳、前阴、后阴皆可成疳。治当败毒调元。
验方
牛粪尖（烧灰存性） 雄黄（各等分）
每钱加冰片二分，乳细搓患处，立愈。
陈实功曰∶痘风疮，是痧痘后毒发未尽，留热肌肤，后被外风侵入，其患先从
细疮作痒，次渐沿开，成片脂水，生痂搔之无度，宜用麦饯散擦之。（《正宗。》）
麦饯散 小儿痘风作痒，叠叠成片，甚则顽麻不知痛痒。
小麦一升炒枯黄色，乘热入钵内，和硫黄四两，白砒一两，研细待冷取起，加
烟胶半斤，川椒三两，生明矾、枯矾各二两，共研细末。临用葱汤洗净，以麻油调
搓，油纸盖扎三日一换，三次即愈。并治白秃神效。
申斗垣曰∶痘出五七日后痒极，动手抓破，急用仙鹤翎在痘上扫一二次即止痒，
就不抓。此神验秘方也。（启玄）
申斗垣曰∶痘已愈，毒未全解，痂虽落尽，止有瘢痕尚在，或黑或凸或凹，或
成疮者，用真白蜜一两涂之，其瘢自消。（《启玄》）
胡公弼曰∶羊骨髓入轻粉研匀涂之，灭瘢。（《青囊》）
申斗垣曰∶痘后疮水不干，在肢体名曰痘疳。用出过蛾的蚕茧不拘多少，每个
入生明矾令满，炭火 研为末，掺之即干。（《启玄》）
又曰∶搔坏痘破烂者，用多年屋上腐草不拘多少，研极细，铺在席子上，令儿
卧其上，自不粘痛，或掺之亦妙。
Douchan (Post-varicella ulceration) refers to the condition where residual toxins from smallpox/varioloid remain uneliminated after recovery, while the body's righteous qi is already deficient. The pathogenic factors invade the hollow orifices, thus causing chancre-like lesions in the mouth, nose, eyes, ears, anterior yin, and posterior yin. Treatment should focus on eliminating toxins and regulating the primal qi.
Empirical Formula:
Niu Fen Jian (Tip of cow dung), calcined to ash but retaining its medicinal nature; Xionghuang (Realgar). Use equal parts of each.
For every qian (approx. 3.7g) of powder, add Bingpian (Borneol) 2 fen (approx. 0.07g). Grind finely and rub onto the affected area for immediate cure.
Chen Shigong stated: Douchengchuang (Varicella wind-lesion) occurs when toxins from measles/smallpox are not fully dispersed after eruption, leaving residual heat in the skin. Subsequently, external wind pathogens invade. The condition begins with itching from fine pustules, gradually spreading into patches exuding serous fluid, forming scabs that are excessively scratched. It is suitable to use Maijiang San (Wheat Paste Powder) for wiping. (*Waike Zhengzong*)
Maijiang San: Indicated for children's varicella wind causing severe itching, presenting as overlapping patches, and in severe cases, causing numbness and loss of sensation.
Take one sheng (approx. 1L) of wheat, stir-fry until dark yellow. While hot, place it in a mortar, mix with Liuhuang (Sulfur) 4 liang (approx. 150g) and Baipi (White Arsenic) 1 liang (approx. 37.5g). Grind finely, allow to cool, then remove. Add Yanjiao (Tobacco gum/resin) half a jin (approx. 300g), Chuanjiao (Sichuan Pepper) 3 liang (approx. 112.5g), Sheng Mingfan (Raw Alum) and Kufan (Calcined Alum) 2 liang (approx. 75g) each. Grind all together into a fine powder. Before use, wash the area with green onion soup. Mix with Mayou (Sesame Oil) and rub onto the lesion. Cover with oil paper and bind; change once every three days. Three applications will result in a cure. This formula is also highly effective for treating Baitu (Tinea capitis/white baldness).
Shen Douyuan stated: Five to seven days after the eruption of varicella, itching becomes extreme, leading patients to scratch and break the lesions. Urgently use Xianheling (Feathers of the crane/heron) to sweep over the lesions one or two times to stop the itching immediately, preventing further scratching. This is a miraculous secret prescription. (*Qixuan Zhizhang*)
Shen Douyuan stated: After varicella has healed, if toxins are not fully resolved, and although scabs have fallen off, scars remain—some black, some convex, some concave, or forming ulcers—apply Zhen Baimi (Pure White Honey) 1 liang (approx. 37.5g). The scars will naturally disappear. (*Qixuan Zhizhang*)
Hu Gongbi stated: Apply Yang Guisui (Sheep bone marrow) mixed evenly with Qingfen (Calomel) to eliminate scars. (*Qingnang Mijuan*)
Shen Douyuan stated: When varicella sores weep continuously without drying up, occurring on the limbs, it is called Douchan. Use silkworm cocoons that have produced moths, quantity unrestricted. Fill each cocoon completely with Sheng Mingfan (Raw Alum). Calcine over charcoal fire, grind into powder, and sprinkle on the affected area to dry the sores. (*Qixuan Zhizhang*)
He also stated: For varicella lesions damaged by scratching and ulcerated, use rotting grass from old roofs, quantity unrestricted. Grind extremely finely, spread on a mat, and let the child lie upon it. This prevents sticking and pain. Alternatively, sprinkling the powder directly on the lesions is also excellent.