诀云∶虚则痒，实则痛。又曰∶诸痒为虚。此固其辨矣。然实即兼热也，虚印兼寒也。盖如疮
疡之痛，必由乎热，今不作痛而作痒，此其无热可知，无热由乎阳虚，阳虚便是寒证，诸有以初起
作痒为火者，皆谬也。且凡痘疮发痒，则多为不起不灌而 陷继之，最可虑也。故凡治痒之法，虽
云当补，然尤不可不温，惟温补则营卫和，气血行而痘自起矣。痘毒既起而透，则多有作痛，尚何
痒哉？故痘于起发之时，则宜痛不宜痒也。然痒有数证，亦当辨治如下∶
一、痘疮初见点便作痒者，此邪在半表半里之间，而进退迟疑总由元气无力，欲达不能也，速
当温补阳气，兼以疏散，但使腠理通畅，则痘自起而痒自止矣。宜六气煎加川芍、白芷、防风、荆
芥之属。若虚在血分而色白者，宜六物煎，或五物煎加减主之。
一、痘疮出齐之后，但是作痒，俱宜保元汤，或六气煎加川芎、当归、防风、荆芥治之，或用十
全大补汤，或用蝉蜕膏。
一、血渗肌肤，咸蜇皮肉而作痒者，亦以气虚而然，宜保元汤加芍药、当归以制血，或加丁香
以治里，官桂以治表，表里俱实，自不作痒。
程氏曰∶凡前后痒 ，宜保元汤加何首鸟、牛蒡子、白芍药。何首鸟须赤白兼用。
一、痘疮干而作痒者，宜养血润燥，以五物煎加防风、荆芥、外用茵陈熏法。
一、痘疮湿而作痒者，宜补气去湿，以四君子汤加防风、荆芥、桂枝以解之，外用菌陈熏法。
一、头面为诸阳之会，若痒而抓破，则泄气最甚，速宜六气煎，或十全大补汤加防风、荆芥、
何首乌之属以培补之。但得复肿复灌而饮食如常则无害，若痒不止而满面抓破者必死。
一、遍身发痒抓破，脓血淋漓者，宜参 内托散，倍加当归及白芷、荆芥、木香，使气和血行，其
痒自止，
外以败草散敷之。
一、疮痒溃烂，粘衣连席难任者，内服十全大补汤加防风、荆芥，外用败草散。
一、痘疮见形而皮肉红艳，起发而皮嫩多水者，其后多致痒 也，急须先期调补之。
一、痘疮将收而痒者，其脓已成，其疮已回，邪散而正复，营卫和畅故痒也。不须服药，但谨
护之，勿令抓破，以致损伤成疮。
一、浆脓初化，脓未成而混身瘙痒不宁者，此恶候也，速当温补气血，用六气煎、六物煎之类
，加以防风、白芷、荆芥之属，必令痒去方保无虑。若痒甚不休，疮坏皮脱，其毒复陷，谓之痒
，必不能活矣。
《活幼心书》云∶凡作痒不止，用荆芥穗以纸束之，用刺痒处，以散郁邪，其痒自止，此屡验
之法。内服消风化毒汤加参、归以解之。
古诀说：虚证表现为瘙痒，实证表现为疼痛。又说：所有的瘙痒都归属于虚证。这确实是辨别的关键。然而，实证往往兼夹热邪，虚证则往往兼夹寒邪。比如疮疡的疼痛，必定是由热邪引起的；现在不痛而痒，这说明没有热邪，没有热邪是因为阳气虚弱，阳气虚弱就是寒证。那些认为初起瘙痒是火邪（实热）的人，都是错误的。况且凡是痘疮发痒，大多是因为痘疹不能隆起、不能灌浆，随后出现凹陷，这是最让人担忧的情况。所以，凡是治疗瘙痒的方法，虽然说应当补益，但尤其不可不温阳，只有温补才能使营卫调和，气血运行通畅，痘疹自然就能隆起。痘毒既然已经隆起透发，就多有疼痛，哪里还会有瘙痒呢？因此，痘疹在起发阶段，适宜疼痛而不宜瘙痒。
然而，瘙痒有多种证型，也应当辨证治疗如下：
第一，痘疮刚出现斑点就开始瘙痒的，这是邪气在半表半里之间，进退迟疑，总归是由于元气无力，想要透达但不能。应当迅速温补阳气，兼用疏散之法，只要使腠理通畅，痘疹自然隆起，瘙痒自然停止。适宜使用六气煎加川芎、白芷、防风、荆芥等药。如果虚损在血分且颜色淡白的，适宜使用六物煎，或五物煎加减主治。
第二，痘疮出齐之后，凡是出现瘙痒的，都适宜使用保元汤，或者六气煎加川芎、当归、防风、荆芥治疗，或者使用十全大补汤，或者使用蝉蜕膏。
第三，血液渗入肌肤，咸味刺激皮肉而导致瘙痒的，也是因为气虚所致，适宜使用保元汤加芍药、当归以制约血行，或者加丁香以治里，官桂以治表，表里充实，自然不再瘙痒。
程氏说：凡是前后出现的瘙痒，适宜使用保元汤加何首乌、牛蒡子、白芍药。何首乌需要赤白两种兼用。
第四，痘疮干燥而瘙痒的，适宜养血润燥，使用五物煎加防风、荆芥，外用茵陈熏洗法。
第五，痘疮湿润而瘙痒的，适宜补气祛湿，使用四君子汤加防风、荆芥、桂枝来解表散邪，外用茵陈熏洗法。
第六，头面是诸阳经汇聚的地方，如果瘙痒抓破，会严重耗泄正气，应当迅速使用六气煎，或十全大补汤加防风、荆芥、何首乌等药来培补正气。只要能使痘疹重新肿胀灌浆，饮食如常，就没有危害；如果瘙痒不止且满脸抓破的，必然死亡。
第七，遍身发痒抓破，脓血淋漓的，适宜使用参内托散，加倍加入当归以及白芷、荆芥、木香，使气和血行，瘙痒自然停止，外用败草散敷贴。
第八，疮疡瘙痒溃烂，粘附衣物和席子难以忍受的，内服十全大补汤加防风、荆芥，外用败草散。
第九，痘疮显现形态而皮肉红艳，起发时皮嫩多水的，其后多会导致瘙痒，必须提前进行调补。
第十，痘疮将要收靥而瘙痒的，此时脓液已成，疮口已回缩，邪气消散而正气恢复，营卫调和通畅，所以会出现瘙痒。不需要服药，只需谨慎护理，不要让它抓破，以致损伤形成疤痕。
第十一，浆液刚开始化生，脓液未成而全身瘙痒不安的，这是恶候，应当迅速温补气血，使用六气煎、六物煎之类，加以防风、白芷、荆芥等药，必须令瘙痒去除才能保全无忧。如果瘙痒剧烈不停，疮坏皮脱，毒邪再次陷入，称为“痒陷”，必然无法存活。
《活幼心书》说：凡是瘙痒不止，用荆芥穗用纸束住，用来刺扎瘙痒处，以疏散郁结的邪气，瘙痒自然停止，这是屡试不爽的方法。内服消风化毒汤加人参、当归来解除它。
The ancient aphorism states: Deficiency manifests as itching, while excess manifests as pain. It is also said that all itching belongs to deficiency. This indeed serves as a key for differentiation. However, excess conditions often involve heat, whereas deficiency conditions often involve cold. For instance, the pain of sores and ulcers must stem from heat; now, since there is no pain but rather itching, it indicates the absence of heat. The absence of heat results from Yang deficiency, and Yang deficiency constitutes a cold syndrome. Those who attribute initial itching to fire (excess heat) are mistaken. Moreover, whenever chickenpox or smallpox lesions itch, it is mostly because the lesions fail to rise and fill with pus, subsequently sinking in, which is most alarming. Therefore, regarding the treatment of itching, although supplementation is indicated, warming is particularly indispensable. Only through warming and tonifying can Ying and Wei (nutritive and defensive Qi) harmonize, Qi and Blood circulate freely, and the lesions naturally rise. Once the toxin has risen and emerged, pain is common, where would itching come from? Thus, during the eruption phase of smallpox, pain is favorable, whereas itching is unfavorable.
However, there are several types of itching, which should be differentiated and treated as follows:
First, when smallpox spots begin to itch immediately upon appearance, this indicates pathogenic factors between the exterior and interior, hesitating to advance or retreat, primarily due to insufficient Yuan Qi (Original Qi), unable to reach the surface. One should rapidly warm and tonify Yang Qi, combined with dispersing methods. As long as the Cou Li (skin pores and interstices) become unobstructed, the lesions will naturally rise, and itching will cease. Liuqi Jian (Six Qi Decoction) added with Chuanxiong Rhizome (Chuanxiong), Angelicae Dahuricae Radix (Baizhi), Saposhnikoviae Radix (Fangfeng), and Schizonepetae Spica (Jingjie) is suitable. If the deficiency lies in the Blood aspect and the color is pale, Liuwu Jian (Six Elements Decoction) or Wuwu Jian (Five Elements Decoction) modified is appropriate.
Second, after the smallpox lesions have fully erupted, any occurrence of itching should generally be treated with Baoyuan Tang (Protect the Origin Decoction), or Liuqi Jian added with Chuanxiong, Angelicae Sinensis Radix (Danggui), Fangfeng, and Jingjie. Alternatively, Shiquan Dabu Tang (Ten Complete Great Tonifying Decoction) or Chantui Gao (Cicada Slough Paste) may be used.
Third, when blood seeps into the skin, causing itching due to the stimulating nature of saltiness on flesh and skin, this is also caused by Qi deficiency. Baoyuan Tang added with Paeoniae Radix Alba (Shaoyao) and Danggui to regulate blood, or Dingxiang (Caryophylli Flos) to treat the interior, and Guirou (Cinnamomi Cortex/Guigui) to treat the exterior, is suitable. When both interior and exterior are solid, itching will not occur.
Master Cheng stated: For itching occurring before and after, Baoyuan Tang added with Polygoni Multiflori Radix (Heshouwu), Arctii Fructus (Niubangzi), and Shaoyao is suitable. Heshouwu should be used in both red and white varieties.
Fourth, for dry smallpox lesions causing itching, nourishing Blood and moistening dryness is indicated. Wuwu Jian added with Fangfeng and Jingjie, externally using Artemisiae Scopariae Herba (Yinchen) fumigation, is appropriate.
Fifth, for damp smallpox lesions causing itching, tonifying Qi and removing dampness is indicated. Sijunzi Tang (Four Gentlemen Decoction) added with Fangfeng, Jingjie, and Cinnamomi Ramulus (Guizhi) to resolve the condition, externally using Yinchen fumigation, is suitable.
Sixth, the head and face are the convergence point of all Yang meridians. If itching leads to scratching and breaking the skin, Qi leakage will be severe. Rapid supplementation with Liuqi Jian or Shiquan Dabu Tang added with Fangfeng, Jingjie, and Heshouwu is required to cultivate and tonify. If the lesions swell and fill again, and appetite remains normal, there is no danger. However, if itching persists and the entire face is scratched open, death is inevitable.
Seventh, for generalized itching with scratched-open lesions oozing pus and blood, Shenqi Neituo San (Ginseng Qi Internal Support Powder) with doubled Danggui, plus Baizhi, Jingjie, and Aquipini Aromatica Rhizoma (Muxiang), is suitable to harmonize Qi and promote Blood circulation, stopping itching. Externally, Baicao San (Defeated Grass Powder) should be applied.
Eighth, for sores that itch, ulcerate, and stick to clothes and mats intolerably, internal administration of Shiquan Dabu Tang added with Fangfeng and Jingjie, and external application of Baicao San, is recommended.
Ninth, when smallpox lesions appear with bright red flesh and tender, watery skin during eruption, itching often follows later. Premature regulation and tonification are urgently required.
Tenth, when itching occurs as smallpox lesions are about to crust over, the pus is formed, and the sores are retracting. This indicates that pathogens are dispersing and Zheng Qi (Upright Qi) is recovering, leading to harmonious Ying and Wei circulation, hence the itching. Medication is unnecessary; careful nursing is required to prevent scratching and scarring.
Eleventh, when blisters are just beginning to form pus but are not yet mature, accompanied by restless whole-body itching, this is an ominous sign. Rapid warming and tonifying of Qi and Blood with Liuqi Jian or Liuwu Jian, added with Fangfeng, Baizhi, and Jingjie, is necessary until the itching ceases to ensure safety. If itching is severe and unceasing, with sores deteriorating and skin peeling off, causing the toxin to sink back in, termed "Itching Sunken," survival is impossible.
The Huayou Xinshu (New Book for Living Infants) states: For persistent itching, bind Jingjie Sui (Schizonepetae Spica) with paper and use it to prick the itchy areas to disperse stagnant pathogens, which stops itching. This is a frequently verified method. Internally, Xiaofeng Huadu Tang (Eliminate Wind and Transform Toxin Decoction) added with Renshen (Ginseng) and Danggui is used to resolve it.