心经火癞蟋蟀连，肝经木癞风厉偏，脾经上狗癞并属，肺经金癞面白兼，肾经水
癞两乌共，胃经酒麻癞总言。
夫癞之为害，较之风证稍轻，然其致害之患一也。但癞愈而形可复，疯愈则元
气难复，癞死者少，疯死者多，然皆非善证耳。（《医学要则》）
心经 火癞如灼之疮，大小不一，或形如癣，裂断皮肤，愈而复发，乃心脏受
毒，病深七年方盛，其蟋蟀癞，亦乃心经毒也。
肝经 木癞初起似蚀癣状，大小不同，形色不一，或遍身高低不定，俗呼为棉花癣。
脾经 土癞或先发热呕吐，身发黄肿，即现 块，大如鸡卵，小如弹丸，或麻木
不仁，穿即成疮，脓气臭秽难闻。
肺经 金癞初发如杨梅疮，上无壳，内泛碎，肉凸起，紫赤溃烂，真如杨梅，毒
入肺经，眉睫毛落，二年鼻梁崩倒，眼塌唇翻，乃金癞之验，若蠹鱼生肺腑，致生
面白细虫，举体艾白斑驳，周身如癣，俨然泥壁风之状，外用熏洗则能取效。白癞
乃风寒暑湿之气，邪毒凑聚，弥满肺窍，久则虫蠹食肺管所致。
肾经 水癞必先得水病而停蓄，又为风湿触激，或生在阴茎，蚀于阴囊，两旁
发肿块横 ，寒热交作，肿痛难忍，渐大而溃变成烂疮，一年病剧，眉发坠落，水
癞之毒在肾，湿久生虫，流注遍身则生青黑赤紫斑驳，以致阴茎痿癞，皮穿肉烂，脓
血臭秽，乌癞乃邪毒入肾，虫食精髓，下虚不救，若在胸肋胁腿臂肋之间，生核如
桃李之状，穿烂臭恶，或似漏疮，或如 疹，手足顽痹，针刺不知，此种之证宜大补气血。
胃经 酒癞因醉卧汗出迎风，邪入于胃所致，似赤非赤，似白非白，大者如钱，
小者如豆，此证最为难治。麻癞由酒毒留滞胃腑，遍发疮毒，状如疥癣，痛痒难忍，
或手足发黑白顽痹，形如雁来鹅掌风之状，或发内痔，头硬而碎，形如 头，遍体皆
然，触之则大痛冷汗，一时即愈。
疯与癞大同小异，但癞轻而疯重，治癞之法，可于疯证门中诸方酌用。
心经火癞对应蟋蟀连，肝经木癞对应风厉偏，脾经上狗癞并属，肺经金癞面白兼，肾经水癞两乌共，胃经酒麻癞总言。
癞这种病症的危害，比风证稍轻，然而它致人受害的后果是一样的。但癞病痊愈后形体可以恢复，疯病痊愈则元气难以恢复，患癞死的少，患疯死的多，然而这些都不是良善的证候。（出自《医学要则》）
心经：火癞如同被火烧灼的疮疡，大小不一，有的形状像癣，撕裂皮肤，愈合后又复发，这是心脏受毒邪侵袭，病情深重，七年左右才发展到盛期。其中的蟋蟀癞，也是心经毒邪所致。
肝经：木癞初起时类似被侵蚀的癣状，大小不同，颜色形态各异，有的遍布全身高低不定，俗称棉花癣。
脾经：土癞有的先出现发热呕吐，身体发黄肿胀，随即现出肿块，大的如鸡蛋，小的如弹丸，或者麻木不仁，刺破后成疮，脓液气味臭秽难闻。
肺经：金癞初发时像杨梅疮，表面没有壳，内部泛碎，肉质凸起，紫红色溃烂，真的像杨梅一样。毒邪进入肺经，导致眉毛睫毛脱落，两年后鼻梁崩塌，眼睛塌陷嘴唇外翻，这是金癞的征验。如果蠹鱼（衣鱼）生于肺腑，导致生出白色细虫，全身艾草白斑驳陆离，周身像癣，俨然有泥壁风的样子，外用熏洗之法能取效。白癞是风寒暑湿之气，邪毒凑聚，充满肺窍，时间久了虫蛀食肺管所致。
肾经：水癞必定先得到水病而停蓄，又受到风湿触激，有的生在阴茎，侵蚀阴囊，两旁发出肿块横生，寒热交替发作，肿痛难忍，逐渐变大溃烂变成烂疮，一年病情加剧，眉毛头发坠落。水癞的毒邪在肾，湿气久了生虫，流注遍身则生出青黑赤紫斑驳，以致阴茎痿软癞损，皮穿肉烂，脓血臭秽。乌癞是邪毒入肾，虫食精髓，下元虚衰无法挽救。如果在胸肋胁腿臂肋之间，生核如桃李之状，穿烂臭恶，或者像漏疮，或者像疹子，手足顽固麻痹，针刺不知痛，这种证候宜用大补气血的方法治疗。
胃经：酒癞因为醉酒后卧倒出汗迎风，邪气进入胃腑所致，颜色似红非红，似白非白，大的如铜钱，小的如豆粒，此证最为难治。麻癞由酒毒留滞胃腑，遍发疮毒，形状像疥癣，痛痒难忍，或者手足发黑白顽痹，形状像雁来鹅掌风的样子，或者发生内痔，头部硬而碎裂，形状像鬼头，遍体都是这样，触碰则大痛冷汗，一时即愈。
Fire leprosy of the Heart Meridian corresponds to Xishuailian, Wood leprosy of the Liver Meridian corresponds to Fenglipian, Dog leprosy of the Spleen Meridian belongs to [Shang], Metal leprosy of the Lung Meridian presents with a white complexion, Water leprosy of the Kidney Meridian involves two types of Wu, and Wine-Ma leprosy of the Stomach Meridian is generally referred to as such.
The harm caused by leprosy (Lai) is slightly less severe than that of wind syndromes (Feng Zheng), yet the detrimental outcome is the same. However, after recovery from leprosy, the physical form can be restored, whereas after recovery from madness/leprosy (Feng), the Yuan Qi (Primordial Qi) is difficult to restore. Few die from leprosy, while many die from Feng; nevertheless, neither is considered a favorable syndrome. (From *Yixue Yaoze*)
Heart Meridian: Fire leprosy resembles burns or sores, varying in size. Some resemble tinea, tearing the skin, recurring after healing. This is due to toxic pathogens invading the Heart, with deep-seated pathology peaking around seven years. The Xishuailai (Cricket Leprosy) is also caused by toxicity in the Heart Meridian.
Liver Meridian: Wood leprosy initially resembles eroded tinea, varying in size, color, and shape. It may appear all over the body with uneven elevation, commonly known as Cotton Tinea.
Spleen Meridian: Earth leprosy may first present with fever and vomiting, yellowing and swelling of the body, followed by the appearance of lumps. These range from the size of a chicken egg to that of a pellet. There may be numbness and insensitivity; upon puncture, it becomes an ulcer with foul-smelling pus.
Lung Meridian: Metal leprosy initially resembles yersinia pestis chancres (Yangmei Chuang). It has no crust on the surface but internal fragmentation, with raised flesh that is purple-red and ulcerated, truly resembling a bayberry. When toxins enter the Lung Meridian, eyebrows and eyelashes fall out. Within two years, the nasal bridge collapses, eyes sink, and lips evert, which are signs of Metal Leprosy. If "dust-eating fish" (body lice/worms metaphorically) reside in the lungs, causing white fine worms to emerge, the body will show mottled patches like mugwort, resembling tinea throughout, akin to "Mubi Feng" (Wall-plaster Wind). External fumigation and washing can be effective. White leprosy is caused by the accumulation of evil toxins from wind-cold, summer-heat, and dampness filling the lung orifices; over time, worms consume the lung tubes.
Kidney Meridian: Water leprosy must first involve water-disease stagnation, further triggered by wind-dampness. It may occur on the penis, eroding the scrotum, with lumps appearing on both sides accompanied by alternating chills and fever, unbearable swelling and pain. It gradually enlarges, ulcerates, and becomes a rotting sore. After one year, the condition worsens, with loss of eyebrows and hair. The toxin of Water Leprosy resides in the Kidneys; prolonged dampness generates worms that circulate throughout the body, causing mottled patches of cyan, black, red, and purple, leading to penile flaccidity and leprosy-like damage, skin perforation, flesh rot, and foul-smelling pus and blood. Black leprosy (Wu Lai) occurs when evil toxins enter the Kidneys, where worms consume essence and marrow, resulting in irreparable lower deficiency. If nodules arise between the chest, ribs, thighs, arms, and flanks, resembling plums or peaches, which ulcerate and smell foul, or resemble fistulas or rashes, causing stubborn numbness in hands and feet where needle pricks are not felt, this syndrome requires substantial tonification of Qi and Blood.
Stomach Meridian: Wine Leprosy results from lying drunk with sweat exposed to wind, allowing evil qi to enter the Stomach. The lesions are reddish yet not fully red, whitish yet not fully white, ranging from the size of a coin to a bean. This syndrome is extremely difficult to treat. Ma Leprosy (Hemp Leprosy) is caused by wine toxin stagnating in the Stomach Fu organ, spreading sores all over the body resembling scabies or tinea, with unbearable itching and pain. Hands and feet may become black and white and numb/stiff, resembling "Goose Palm Wind." Internal hemorrhoids may develop, hard and fragmented, resembling "Ghost Heads," affecting the whole body. Touching them causes severe pain and cold sweat, resolving momentarily.
Madness/Leprosy (Feng) and Leprosy (Lai) are largely similar but differ in severity; Lai is mild, while Feng is severe. The treatment methods for Lai can be selected from the formulas in the Feng Syndrome section according to circumstances.