夫体虚受风热湿毒之气，则生疮。痒痛 肿多汁，壮热，谓之恶疮。而湿毒瓦斯盛，体外
虚内热，其疮渐增，经久不瘥，为久恶疮。
疮者，由肤腠虚，风湿之气，折于血气，结聚所生。多着手足间，递相对，如新
生茱萸子，痛痒，抓搔成疮，黄汁出，浸淫生长，拆裂，时瘥时剧，变化生虫，故名
肤腠虚，风湿搏于血气，则生 疮。若湿气少，风气多者，其 则干燥，但痒
，搔之白屑出，干枯拆痛。此虫毒瓦斯浅在皮肤，故名燥 疮也。
肤腠虚，风湿搏于血气，生 疮。若风气少，湿气多，其疮痛痒，搔之汁出，常濡
湿者，此虫毒瓦斯深，在于肌肉内故也。
疮积久不瘥者，由肤腠虚，则风湿之气停滞，虫在肌肉之间，则生长，常痒痛，
故经久不瘥。
癣病之状，皮肉隐胗如钱文，渐渐增长，或圆或斜，痒痛，有匡郭，里生虫，搔之有汁
。此由风湿邪气，客于腠理，复值寒湿，与血气相搏，则血气痞涩，发此疾。
按九虫论云∶蛲虫在人肠内，变化多端，发动亦能为癣，而癣内实有虫也。
《养生方》云∶夏勿露面卧，露下堕面上，令面皮浓，及喜成癣。
干癣，但有匡郭，皮枯索，痒，搔之白屑出是也。皆是风湿邪气，客于腠理，复值寒湿
，与血气相搏所生。若其风毒瓦斯多，湿气少，故风沉入深，故无汁，为干癣也。其中亦生虫
When the body is deficient and susceptible to pathogenic factors of wind, heat, dampness, and toxicity, ulcers (Chu, sores) will arise. If the ulcer presents with itching, pain, swelling, copious discharge of pus, and high fever, it is called Ewu Chuang (Severe Ulcer). When damp-toxic qi is exuberant, causing exterior deficiency and interior heat, the ulcer gradually increases in number and fails to heal for a long time; this is termed Jiu Ewu Chuang (Chronic Severe Ulcer).
Ulcers are generated by the deficiency of skin and interstices (Fukou), where wind-damp pathogenic factors obstruct the flow of blood and qi, leading to aggregation and condensation. This condition often occurs between the hands and feet, appearing symmetrically, resembling newly formed fruits of *Euodia rutaecarpa*. It is characterized by pain and itching; scratching leads to ulceration with yellow discharge, spreading and infiltrating, cracking, fluctuating between remission and exacerbation, and potentially transforming into parasites, hence the name.
When skin and interstices are deficient, wind-damp pathogens contend with blood and qi, generating ulcers. If dampness is slight and wind is predominant, the lesion becomes dry, manifesting primarily as itching. Scratching yields white scales, and the skin becomes dry, cracked, and painful. Since the parasitic toxin is superficial and resides in the skin, it is named Zao Chuang (Dry Ulcer).
Similarly, when skin and interstices are deficient and wind-damp pathogens contend with blood and qi, ulcers form. If wind is slight and dampness is predominant, the ulcer is both painful and itchy. Scratching produces discharge, and the area remains perpetually moist. This indicates that the parasitic toxin is deep-seated within the muscles.
The reason ulcers fail to heal over a long period is due to the deficiency of skin and interstices, which causes wind-damp pathogens to stagnate. Parasites proliferate between the muscles, causing persistent itching and pain, thus preventing healing for an extended duration.
The manifestations of Xuan Bing (Tinea/Psoriasis-like Disease) include hidden papules on the skin and flesh resembling coin patterns, gradually expanding in circular or oblique shapes, accompanied by itching and pain, distinct borders (Kuangguo), internal parasitic generation, and discharge upon scratching. This arises from wind-damp evil qi lodging in the interstices, compounded by cold-dampness, which contends with blood and qi, causing obstruction and stasis, thereby triggering the disease. According to the *Jiu Chong Lun* (Treatise on Nine Parasites): Pinworms (*Ascaris lumbricoides*/Enterobius vermicularis contextually) reside in the intestines, undergo various transformations, and their activation can induce tinea; indeed, there are parasites within tinea lesions. The *Yangsheng Fang* (Prescriptions for Health Preservation) states: Do not sleep outdoors in summer; dew falling on the face thickens the facial skin and predisposes one to developing tinea.
Gan Xuan (Dry Tinea) is characterized by distinct borders only, with withered, rough skin, itching, and white scales upon scratching. These are all caused by wind-damp evil qi lodging in the interstices, combined with cold-dampness, contending with blood and qi. If wind-toxin is abundant and dampness is scarce, the wind sinks deeply, resulting in no discharge; this is defined as Gan Xuan. Parasites may also be present within.