小儿气禀纯阳，脏腑易得生热，阴阳气迁，熏蒸于外，致令身热也。肝热则两眼赤肿，
流泪羞明，或生翳瘴。心热则口内生疮，小便赤，淋沥不通。肺热则鼻衄不止，大便秘结。
脾热则生重舌木舌，流涎流沫。胃热则口作臭。肾热则耳聋，或出脓血。至于五脏蕴蓄风热毒风，
令儿面赤如绯，五心烦热，四肢温壮，痰涎壅盛，目涩多渴，上冲咽喉，则与气血相搏，结
聚壅盛而成喉闭也。大抵小儿多因热生风，风生惊。欲儿无病，先清其热，此所谓拔本塞源
者也。
杨氏曰∶小儿病，惟热居多。夫热有潮热、惊热、夜热、余热、实热、虚热、表热、里热、
食热、疳热、壮热、烦热、气热、血热、积热、郁热、风热、客热、癖热、疮疹热，诸热大
同而小异。热之始发，必有所因也。潮热者，发歇有时。惊热者，颠叫恍惚。夜热者，夕发旦止。
余热者，寒邪未尽。实热者，壮盛壅滞。虚热者，气血俱虚，脾胃虚热。表热者，轻手按
之便觉，或因腠理感伤。里热者，大便秘结，小便赤黄。食热者，浓味之变，乳母所遗。
疳热者，腹大面黄，身热形瘦。壮热者，一向不止。烦热者，心燥不安。积热者，颊赤口疮。
风热者，汗出风热。客热者，去来不定。癖热者，腹中有块。郁热者，怫热闷乱。痰热者，
涎嗽引饮。疮疹热者，耳、鼻尖冷。诸证得之，各有所归，其间或有三两证交互者，宜随其
轻重而处治之。
Children are constitutionally endowed with "pure Yang" (Chunyang, a state of vigorous growth and metabolic activity), making their Zang-Fu organs prone to generating internal heat. As Yin and Qi undergo changes, the steaming effect of heat manifests externally, resulting in fever. Liver Heat (Gan Re) causes redness and swelling of both eyes, tearing, photophobia, or the formation of corneal opacities (Yi Zhang). Heart Heat (Xin Re) leads to oral ulcers, dark urine, and dysuria with dribbling. Lung Heat (Fei Re) results in persistent epistaxis and constipation. Spleen Heat (Pi Re) causes double tongue (Zhong She), wooden tongue (Mu She), drooling, or foaming at the mouth. Stomach Heat (Wei Re) causes halitosis. Kidney Heat (Shen Re) leads to deafness or the discharge of pus and blood from the ears. Furthermore, if Wind-Heat (Feng Re), Toxic-Wind (Du Feng), etc., accumulate within the five Zang organs, it may cause the child's face to turn crimson, accompanied by vexation and heat in the five centers (Wu Xin Fan Re - palms, soles, and chest), warmth and fullness in the four limbs, copious phlegm and saliva, dry eyes, excessive thirst, and upward rushing of heat to the throat. This heat clashes with Qi and Blood, condensing and obstructing to form Throat Closure (Hou Bi - acute obstruction of the airway due to swelling). Generally speaking, children often develop Wind (Feng) due to Heat, and Convulsions (Jing) due to Wind. To prevent illness in children, one must first clear their internal Heat; this is referred to as "pulling up the root and blocking the source" (Ba Ben Sai Yuan - addressing the fundamental cause).
Yang Shi stated: Among pediatric diseases, Heat syndromes are predominant. Heat syndromes include Tidal Fever (Chao Re), Fright Heat (Jing Re), Night Fever (Ye Re), Lingering Heat (Yu Re), Excess Heat (Shi Re), Deficiency Heat (Xu Re), Exterior Heat (Biao Re), Interior Heat (Li Re), Food Heat (Shi Re), Malnutrition Heat (Gan Re), High Fever (Zhuang Re), Vexatious Heat (Fan Re), Qi Heat (Qi Re), Blood Heat (Xue Re), Accumulation Heat (Ji Re), Stagnant Heat (Yu Re), Wind-Heat (Feng Re), Guest Heat (Ke Re), Mass Heat (Pi Re), and Rash Heat (Chu Zhen Re). These various heats share commonalities but have minor differences. The onset of any heat syndrome must have a specific cause. Tidal Fever occurs at regular intervals. Fright Heat is characterized by screaming and trance-like states. Night Fever starts in the evening and resolves by morning. Lingering Heat indicates that Cold pathogens have not been fully expelled. Excess Heat involves robust vitality but pathogenic stagnation. Deficiency Heat arises from dual deficiency of Qi and Blood, specifically Spleen-Stomach deficiency heat. Exterior Heat is felt upon light palpation of the skin, often due to invasion of the Cou Li (interstitial spaces) by external pathogens. Interior Heat presents with constipation and dark yellow urine. Food Heat results from the transformation of rich flavors or transmission from the nursing mother's diet. Malnutrition Heat is characterized by abdominal distension, sallow complexion, fever, and emaciation. High Fever refers to continuous, unremitting fever. Vexatious Heat involves mental restlessness and anxiety. Accumulation Heat manifests as flushed cheeks and oral ulcers. Wind-Heat occurs after sweating when exposed to wind. Guest Heat comes and goes unpredictably. Mass Heat involves abdominal masses. Stagnant Heat presents with internal oppression, heat, and confusion. Phlegm-Heat is marked by salivation, cough, and a desire to drink. Rash Heat is characterized by coldness in the ears and nose tip. Each of these syndromes has its specific attribution. Occasionally, two or three syndromes may interact; treatment should be administered according to the severity of the condition.