Etiology and Pathology
Cough has two principal types of causes, exogenous and endogenous.
Exogenous cough is due to attack by an exogenous pathogenic evil on the lung system. Most commonly Wind attacks first and is subsequently joined by Cold, Heat, Dryness or the others. Attack on the lung system disturbs the dispersing and descending actions of lung-Qi, and lung-Qi ascends abnormally causing illness. Thus, exogenous cough is a condition of strength of the exogenous evil. If the exogenous evils cannot be removed promptly, there may be further development or complication, such as Wind-Cold transforming into Heat, Wind-Heat transforming into Dryness, or Lung-Heat transforming tejh normal fluids into the pathogenic Phlegm.
Endogenous cough is due to internal injury disturbing the functions of the zang-fu organs and causing disordered dispersion and abnormal rise of lung-Qi. The internal injury may result from a variety of causes. It may be due to over-stimulation by the passions, so that liver-Qi becomes stagnant and transforms into Fire; the liver-Qi and Fire then move upward along the pathways of the meridians and attack the lung. It may be due to intemperate diet, with excessive spices, fats, alcohol or smoking burning the stomach and the lung. It may be due to impaired transportation by the spleen, so that turbid Phlegm arises endogenously and permeates the lung. It may be due to deficiency of both kidney-Qi and kidney-essence brought about by excessive fatigue or sexual indulgence, so that Yin is injured and Qi exhausted; and this leads to the impairment of the lung’s ability to govern Qi. Similarly, chronic illnesses may bring about insufficiency of the lung with injury to Yin and exhaustion of Qi.
Whether the cough is exogenous or endogenous, the pathological mechanism is injury to the lung system, with disturbance of its dispersion and purifying functions – this injury being mediated mainly by Phlegm and Fire. Prolonged exogenous cough can transform into internal injury. Endogenous cough generally results from the weakening of the lung and the Defensive Level; it is also readily induced or aggravated by exogenous evils attacking when the body is in a weakened state.
Cough is a symptom. In general, exogenous cough has a rapid onset and a short course. Endogenous cough tends to have a more prolonged course and is often accompanied by symptoms of injured visceral organs. The characteristics of the most common illnesses with cough are listed here.
Wind-Cold attacking the lung: cough with throat itch; thin and white sputum; nasal mucosal congestion with clear discharge; or cold-aversion, fever, headache and body aches. The pulse is floating and tight, and the tongue coating is thin and white.
Wind-Heat attacking the lung: frequent and intense cough, with viscous and yellow sputum that is difficult to expectorate; thick yellow nasal discharge; thirst or fever. The tongue is red, with a thin yellow coating, and the pulse is floating and rapid.
Dryness attacking the lung: cough without sputum or with slight viscous sputum that is difficult to expectorate, or blood-streaked sputum; and dry lips and nose, with strong thirst. The tongue is dry, with a thin white or thin yellow coating, and the pulse is floating and tight or floating and rapid.
Liver-Fire attacking the lung: paroxysmal cough with each spell difficult to stop, with thick sputum in the throat that is very difficult to expectorate; flushed face with dry throat; chest and subcostal pressure and pain; and a dry mouth with a bitter taste. The tongue coating is thin, yellow and dry, and the pulse is taut and rapid.
Phlegm-Dampness accumulating in the lung: recurrent cough with much viscous white or gray sputum that is easy to expectorate, the cough stopping when the sputum is expectorated; hoarse voice; chest and epigastric tightness; anorexia; and tiredness. The tongue coating is white and greasy, and the pulse is soft and slippery.
Phlegm-Heat blocking the lung: cough with heavy breathing; copious sputum that is viscid and difficult to expectorate; flushed face; dry mouth; or fever. The tongue is red, with a yellow and greasy coating, and the pulse is slippery and rapid.
Yin deficiency of the lung: dry cough without sputum or with blood-streaked sputum; the cough is short but explosive, or hoarse; dry mouth and throat; or low-grade fever, or sometimes hotness in the five centers. The tongue is red with scant coating, and the pulse is threadlike and rapid.
Qi insufficiency: cough with copious thin sputum; shortness of breath; weakness; and spontaneous sweating.
Key Points of Analysis
Endogenous versus Exogenous
In general, exogenous cough arises as a new illness, with abrupt onset following exposure to cold, and is accompanied by nasal mucosal congestion and discharge, sneezing, an itchy throat, distending headache, generalized body aches, aversion to wind or cold, and fever. Endogenous cough is generally chronic, with slow onset. There usually are symptoms of other visceral organs, such as fatigue and weakness, chest distention, flank pain, anorexia, diarrhea, or other symptoms.
Quality and Timing of Cough
A vigorous cough indicates an illness of exogenous strength, whereas a weak or soft cough indicates an illness of deficiency. Frequent cough during the day, nasal mucosal congestion, and a nasal quality to the sound generally indicate an exogenous cough. Cough that begins on arising in the morning and comes in repeated and worsening paroxysms, with a hoarse sound, is mainly due to turbid Phlegm. Cough that is worse when recumbent at night and that persists, with shortness of breath and weakness, indicates deficiency of Qi or Yin of the lung.
Color, Texture and Amount of Sputum
Cough with scant sputum or dry cough is mainly due to Dryness-Heat or Yin deficiency. A copious amount of sputum generally indicates Phlegm-Dampness, Phlegm-Heat, or deficiency-Cold. White and thin sputum indicates Wind or Cold. White but thick or viscous sputum indicates Dampness. Yellow and viscous sputum indicates Heat. Blood-streaked sputum is mostly due to Heat injuring the lung or dryness of the lung due to Yin deficiency.
In general, the treatment of exogenous cough should focus on unblocking the lung and expelling the exogenous pathogenic evil. The treatment of endogenous cough will depend upon the interplay between strength and deficiency of the genuine, upon the rapidity of disease progression, upon the relative urgency of root and appearance, and upon the specific deficiency and the strength.
Cough due to Wind-Cold Attack
Symptoms. Main symptoms: cough with thin white sputum and throat itch. Frequently accompanying symptoms: nasal mucosal congestion with clear discharge; sneezing; cold-aversion without sweating; headache; and joint pain. The tongue coating is white and the pulse is floating.
Therapeutic Principle. Expel Wind and Cold, and disperse and unblock lung-Qi.
Treatment. Several formulas are commonly used, including San Ao Tang, Zhi Sou San, and others. San Ao Tang emphasizes the unblocking of the lung and the elimination of Cold, whereas Zhi Sou San (Cough-Stopping Powder) emphasizes unblocking of the lung and dispersal of Wind.
The composition of Zhi Sou San is as follows: jiegeng (Platycodon) 10 g, jingjie (Schizonepeta) 10 g, ziwan (Aster tartaricus) 10 g, baibu (Stemona) 10 g, baiqian (Cynanchum) 10 g, chenpi (Citrus tangerina) 6 g and gancao (Glycyrrhiza) 3 g.
If symptoms of the exterior are particularly severe, fangfeng (Saposhnikovia) and Qianghuo (Notopterygium) may be added.
For Wind-Cold combined with Dampness, with the symptoms of cough with viscid sputum, chest tightness and a greasy tongue coating, add processed banxia (Pinellia) and houpo (Magnolia).
In an illness of interior-Heat-exterior-Cold, known to lay persons as “Fire wrapped by Cold,” the symptoms are cough with a hoarse sound, thick viscid sputum that is difficult to expectorate, chest pain from coughing, cold-intolerance and nasal mucosal congestion. Alternately, there may be fever, thirst with sore throat, or in severe cases retrograde flow of Qi producing wheezing. The tongue is red, with a white or yellow and greasy coating, and the pulse is slippery and rapid. A patient with syndrome of interior-Heat-exterior-Cold should be treated with Ma Xing Shi Gan Tang to disperse Cold and cool Heat.
Cough due to Wind-Heat Attack
Main Symptoms. Cough with white or yellow and viscid sputum that is difficult to expectorate; dry mouth; sore throat; yellow nasal discharge; fever, sweating, cold-aversion; and headache. The tongue coating is thin and yellow, and the pulse floating and rapid.
Therapeutic Principle. Dispel Wind, cool Heat, unblock the lung and relieve cough.
Treatment. Sang Ju Yin.
For severe cough, add yuxingcao (Houttuynia), pipaye (Eriobotrya japonica), beimu (Fritillaria) and aidicha (Ardisia japonica).
If the Heat evil is particularly strong, with prominent fever and thirst, add huangqin (Scutellaria), zhimu (Anemarrhena) and gualou (Trichosanthes) to enhance the ability of the formula for eliminating Lung-Heat.
If throat pain is severe, add shegan (Belamcanda).
For epistaxis or blood-streaked sputum, due to Wind-Heat injuring the vessels, add baimaogen (Imperata) and oujie (Nelumbo nucifera, node).
If Wind-Heat is aggravated by Summer Heat, the typical symptoms are cough, chest tightness, irritability, thirst, dark urine, a red tongue with thin coating and a soft but rapid pulse. It is appropriate to use xiangru (Elsholtzia spendens), Qianhu (Peucedanum), fresh huoxiang (Agastache), peilan (Eupatorium) and Qingheye (Nelumbo, leaf), or Yi San (Six-One Powder), to disperse Wind and relieve Summer Heat.
If Heat has injured the body fluids, add nanshashen (Adenophora tetraphylla), tianhuafen (Trichosanthes) and lugen (Phragmites) as appropriate.
Cough due to Dryness
Main Symptoms. Cough with scant sputum, or slight amount of viscid sputum that is difficult to expectorate or that is blood-streaked; dry and sore throat; and dry nose and lips. When the cough is severe there may be chest pain. In the initial stages there may be cold-aversion, fever, headache and other symptoms of the exterior. The tongue coating is thin and white or thin, yellow and dry. The tongue tip is red. The pulse is floating and tight, or threadlike and rapid, or unchanged.
Therapeutic Principle. In the case of Heat-Dryness, unblock the lung, moisten Dryness, disperse Wind and clear Heat. In the case of Cold-Dryness, disperse Wind and Cold, moisten the lung and stop the cough.
Treatment. Heat-Dryness. Sang Xing Tang (Mulberry and Apricot Decoction). The composition is as follows: sangye (Morus) 10 g, xingren (Prunus) 10 g, nanshashen (Adenophora tetraphylla) 12 g, beimu (Fritillaria) 6 g, dandouchi (Glycine max) 6 g, zhizi peel (Gardenia jasminoides) 6 g and pear peel 6 g.
If symptoms of Dryness-Heat are prominent, add maimendong (Ophiopogon), yuzhu (Polygonatum), zhimu (Anemarrhena) and shigao (gypsum).
If headache and fever are severe, add bohe (Mentha), lianqiao (Forsythia) and chantui (Cryptotympana).
If throat pain is severe, add xuanshen (Scrophularia) and mabo (Calvatia lilacina).
If there is epistaxis as well, add baimaogen (Imperata) and shengdihuang (Rehmannia).
Cold-Dryness. Xing Su San. When applying this herbal formula, use the standard of warming without drying and moistening without cooling. If cold-intolerance without sweating is prominent, add jingjie (Schizonepeta) and fangfeng (Saposhnikovia).
Cough due to Phlegm-Dampness
Main Symptoms. Cough with much white and viscous sputum; chest and epigastric tightness; anorexia; and weakness in the limbs. The tongue coating is white and greasy, and the pulse is soft and slippery.
Therapeutic Principle. Strengthen the spleen, dry Dampness, regulate Qi and dissipate Phlegm.
Treatment. Er Chen Tang.
If Phlegm and Dampness are severe, with copious sputum and prominent epigastric distention, add cangzhu (Atractylodes), houpo (Magnolia), yiyiren (Coix) and xingren (Prunus armeniaca) to enhance the ability to dry Dampness and dissipate Phlegm.
If there is Cold as well, add ganjiang (Zingiber), xixin (Asarum), and baijiezi (Brassica alba) to warm and dissipate.
If there is Wind as well, add bile-treated nanxing (Arisaema erubescens) and baifuzi (Typhonium giganteum) to dispel Wind and dissipate Phlegm.
If gelled Phlegm causes indigestion, resulting in much sputum, chest tightness, anorexia, a greasing tongue coating and a slippery pulse, use in conjunction with San Zi Yang Qing Tang (Three Seeds Decoction for the Aged) to regulate Qi, dissipate Phlegm and promote food digestion. The composition of San Zi Yang Qing Tang is as follows: baijiezi (Brassica alba) 10 g, zisuzi (Perilla) 10 g and laifuzi (Raphanus) 10 g.
If Cold-Phlegm is severe, with white viscous and foamy sputum and cold-aversion, add ganjiang (Zingiber).
If the spleen is insufficient due to chronic illness, with faint cough sounds, shortness of breath, lassitude and proneness to sweating, add dangshen (Codonopsis), baizhu (Atractylodes) and fried gancao (Glycyrrhiza) to support Earth (Spleen) in order to generate Metal (Lung).
Cough due to Phlegm-Heat
Main Symptoms. Cough with viscid yellow sputum that is difficult to expectorate, sometimes blood-streaked; chest tightness; a dry mouth with a bitter taste; and sore throat. The tongue coating is yellow and greasy, or yellow and white. The pulse is slippery and rapid.
Therapeutic Principle. Cool Heat to clear the lung, eliminate Phlegm and stop cough.
Treatment. Qing Jin Hua Tan Tang (Metal-Clearing and Phlegm-Dissipating Decoction). Its composition is as follows: huangqin (Scutellaria) 10g, zhizi (Gardenia jasminoides) 10 g, jiegeng (Platycodon) 6 g, maimendong (Ophiopogon) 9 g, beimu (Fritillaria) 9 g, juhong (Citrus tangerina, orange scraping from the peel) 9 g, ful-ing (Poria cocos) 9g, sangbaipi (Morus) 10 g, zhimu (Anemarrhena) 10 g, parched gualou seed (Trichosanthes) 10 g, and gancao (Glycyrrhiza) 3 g.
For severe accumulation of Heat in the lung, with cough and wheezing, yellow purulent or putrid sputum, high fever and thirst, remove jiegeng and chenpi but add jinyinhua (Lonicera), yuxingcao (Houttuynia), shigao (gypsum), tinglizi (Lepidium) or similar herbs that cool Heat and release the lung.
If the body fluids are damaged by Phlegm-Heat, add beishashen (Glehnia), tianmendong (Asparagus chochinchinensis) and tianhuafen (Trichosanthes) as appropriate.
Cough due to Liver-Fire Attacking the Lung
Main Symptoms. Dyspnea with paroxysmal cough that is difficult to stop; in severe cases, there may be blood-streaked sputum or hemoptysis; pain in both the chest and the epigastrium; irascibility; fever; a bitter taste in the mouth; and a flushed face and red eyes. The tongue coating is thin, yellow and dry. The pulse is taut and rapid.
Therapeutic Principle. Clear the liver and purge the lung to stop cough.
Treatment. Dai Ge San combined with Xie Bai San.
Dai Ge San (Indigo and Concha Powder) has the following composition: Qingdai (Baphicacanthus cusia) 6 g and haigeqiao (Cyclina sinensis) 10 g.
Xie Bai San (Lung-Purging Powder) has the following composition: digupi (Lycium) 30 g, parched sangpi (Morus alba) 30 g, jingmi (Oryza sativa) 10 g and gancao (Glycyrrhiza) 3 g.
For blazing Fire with frequent cough it is appropriate to add zhizi (Gardenia jasminoides), mudanpi (Paeonia suffruticosa), beimu (Fritillaria) and pipaye (Eriobotrya japonica) to enhance Heat cooling and cough relief.
If lodged Fire injures the body fluids, add beishashen (Glehnia) and maimendong (Ophiopogon).
Cough due to Yin Deficiency of the Lung
Main Symptoms. Dry cough without sputum, or scant sputum that is difficult to expectorate, or hemoptysis. The tongue is red with little coating. The pulse is threadlike and rapid.
Therapeutic Principle. Augment Yin to moisten the lung and relieve cough.
Treatment. Shashen Maidong Tang (Adenophora-Ophiopogon Decoction). Its composition is as follows: nanshashen (Adenophora tetraphylla) 9g, yuzhu (Polygonatum) 15 g, raw gancao (Glycyrrhiza) 3 g, sangye (Morus) 9 g, maimen-dong (Ophiopogon) 9 g, biandou (Dolichos lablab) 5 g, tianhuafen (Trichosanthes) 9g, zhimu (Trichosanthes) 10 g, beimu (Fritillaria) 10 g, tianmendong (Asparagus chochinchinensis) 10 g, baihe (Lilium) 10 g and shengdihuang (Rehmannia) 10 g.
If the cough is severe, add baibu (Stemona), ziwan (Aster tartaricus) and kuan-donghua (Tussilago farfara) to moisten the lung and stop the cough.
If the sputum is viscid and difficult to expectorate, add powdered haigeqiao (Cyclina sinensis) to cool Heat and dissolve sputum.
For hemoptysis add baiji (Bletilla), Qiancao (Rubia) and oujie (Nelumbo nucifera, node) to stop bleeding.
For cough with tachypnea (rapid respiration) add wuweizi (Schisandra) and hezi (Terminalia chebula).
Cough due to Qi Deficiency of the Lung
Main Symptoms. Weak cough with much clear and thin sputum; shortness of breath; fatigue; wind-aversion; spontaneous sweating; and low resistance. The tongue is pale with a thin and white coating, and the pulse is feeble.
Therapeutic Principle. Augment lung-Qi, dissipate Phlegm and relieve cough.
Treatment. Bu Fei Tang (Lung-Nourishing Decoction). Its composition is as follows: renshen (Panax) 10 g, huangqi (Astragalus) 10 g, shudihuang (Rehmannia) 10 g, sangbaipi (Morus) 10 g, ziwan (Aster tartaricus) and wuweizi (Schisandra) 6g.
For abundant thin sputum due to spleen insufficiency, subtract sangbaipi and add baizhu (Atractylodes), fuling (Poria) and kuandonghua (Tussilago farfara) to enhance the effect of invigorating Qi of the formula, replenishing the spleen and resolving Phlegm to relieve cough.
In the acupuncture treatment of cough, the most commonly selected principal acupoints are Feishu (BL-13) and Hegu (LI-4). Auxiliary acupoints are also often selected. If sputum is copious, add Fenglong (ST-40). For throat itch and cough add Tiantu (CV-22). For chest tightness add Neiguan (PC-6) and Tanzhong (CV-17). For chronic cough with a weak constitution the acupoints Feishu (BL-13), Shenshu (BL-23) and Pishu (BL-20) may be selected.
In general, for exogenous cough use the reducing method. For endogenous cough use the mild reinforcing and mild reducing methods; moxibustion may also be incorporated as appropriate.
Wind-Cold attacking the lung: select Feishu (BL-13), Dazhu (BL-11), Fengmen (BL-12) and Lieque (LU-7). Use filiform needles and apply the retention technique. Apply moxibustion.
Wind-Heat attacking the lung: select Feishu (BL-13), Yuji (LU-10) and Hegu (LI-4). Use filiform needles and shallow insertion with the reducing method. Do not apply moxibustion.
Wind-Dryness attacking the lung: select Feishu (BL-13), Pohu (BL-42), Chize (LU-5) and Fuliu (KI-7). Use filiform needles and the mild reinforcing and reducing method. Do not apply moxibustion.
Phlegm-Dampness accumulating in the lung: select Feishu (BL-13), Taiyuan (LU-9), Zhangmen (LR-13), Taibai (SP-3) and Fenglong (ST-40). Use filiform needles and the mild reinforcing and reducing method. Moxibustion can be applied.
Heat-Phlegm blocking the lung: select Feishu (BL-13), Zhongfu (LU-1), Chize (LU-5) and Fenglong (ST-40). Use filiform needles and the reducing method. Do not apply moxibustion.
Liver-Fire attacking the lung: select Feishu (BL-13), Chize (LU-5), Yan-glingquan (GB-34) and Taichong (LR-3). At the acupoints of the Liver Meridian of Foot-Jueyin use the reducing method. At the acupoints of the Lung Meridian of Hand-Taiyin use the mild reinforcing and reducing method. Do not apply moxibustion.
Deficiency of Lung-Yin: select Feishu (BL-13), Gaohuangshu (BL-43), Shufu (KI-27) and Taixi (KI-3). Use filiform needles and the reinforcing method. Do not apply moxibustion.
The patient was a 34-year old female who had a cough for nearly 4 weeks.
During the last 10 days the cough had become frequent and violent, and productive of sputum that was a mixture of white foam-like material and yellow viscous streaks. Coughing was accompanied by pain in the chest and especially in the epigastrium, worsened by pressure, and by chest tightness. Her respiration was rapid. She also had pain in her head, neck and the body. She was intolerant of cold and had fluctuating fever and little sweating, and her distal extremities were very cold.
She had an itch in the throat and a dry mouth, but no desire to drink. She had not defecated for several days.
Her temperature was 38.3°C (101°F). Her tongue was pale with a thin and yellow but moist coating. Her pulse was threadlike, at a rate of 84 beats per minute. Auscultation of the lung showed no abnormality. The abdomen was flat without any fixed tenderness. Her total white blood cell count was 12,200, with 84% neutrophils, 2% acidophils and 14% lymphocytes. Chest fluoroscopy was normal.
Diagnosis: Exogenous cough, with Wind-Cold lodged in the exterior in the Defensive Level and turbid Phlegm gelled in the lung.
Therapeutic Principle: Use acrid-warming to release the exterior, unblock the lung and dissipate Phlegm.
Treatment and Course: She was treated with a combination of Mahuang Tang and Guizhi Houpo Xingzi Tang (Cinnamon-Magnolia-Apricot Decoction) with modifications. The prescription had the following composition: fried mahuang (Ephedra) 3g, guizhi (Cinnamomum) 3g, bitter xingren (Prunus armeniaca) 10 g, gancao (Glycyrrhiza) 3 g, houpo (Magnolia) 3 g, stirfried zisuzi (Perilla) 10 g, stirfried lai-fuzi (Raphanus) 10 g, banxia (Pinellia) 6g, gualou (Trichosanthes) 15 g, stirfried zhishi (Citrus aurantium) 10 g and chenpi (Citrus tangerina) 5 g.
Following one dose (a package of prescribed herbs) she had profuse sweating and the fever subsided. The pains decreased gradually. The cough became milder but still recurred in spells and still induced epigastric pain. The sputum was still large in amount and was an intermixed white and yellow. Following three more daily doses the cough was relieved and defecation became unobstructed, with only slight residual tenderness in the epigastrium. The prescription was continued for another day to consolidate the gains. The patient recovered completely and was discharged from the hospital.