Clinical Notes on Treating Allergic Diseases with TCM
Haze weather has triggered a broad outbreak of respiratory disease; lately I have seen many patients with allergic asthma, allergic rhinitis, and allergic skin disease. Below I write up my own diagnostic and therapeutic experience with chronic allergic disease.
The great Japanese kampo physician Yumoto Kyushin summarized the pathogenic factors in the human body as three toxins: water toxin, blood toxin, and flesh toxin. He therefore held that the root of TCM treatment lies in expelling these three toxins; once they are removed, the patient's suffering follows. I deeply agree with this medical view.
Allergic diseases are typical latent-pathogen (fu xie) disorders, especially latent pathogen in the lung system. In treatment, as long as the lung's latent pathogen is not fully expelled, allergic diseases will never cease. The lung governs respiration and controls the skin and body hair; therefore when the lung harbors latent pathogen, not only the entire respiratory tract is affected, but the skin as well. In TCM, respiratory disease and skin disease are treated by the same logic—both primarily by treating the lung.
The lung is a delicate organ, intolerant of cold or heat. Changes in environmental temperature and humidity clearly affect the patient's lung. The source of many allergic diseases can be traced back to early childhood or adolescence. Allergic disease often arises when an initial acute respiratory illness is improperly managed, leaving residual pathogen never fully expelled; hence a slight external contraction triggers an acute attack.
Western medicine tests allergens to determine treatment plans; in my own clinical experience this is a very mechanical approach. If patients receive root-tracing TCM treatment, most need not fear allergens and can be completely cured. I myself am proof: years of asthma were cured after I taught myself TCM and treated myself; my previously easily affected constitution is no longer so sensitive.
From my experience living in both the North and South, northern allergic patients are mostly dominated by lung heat, while southern ones are mostly dominated by lung cold. The North is bitterly cold; in winter parents bundle their infants too tightly, so northern children easily develop in childhood the root of constrained lung heat that cannot vent—what Professor Zhang Juren called an exterior-cold, interior-heat constitution. The South is warm and humid; winters are damp-cold, and insufficient clothing easily leads to cold-damage, producing lung cold mixed with water qi.
The lung is the heaven among the five zang. Latent pathogen lingering in the lung over a long time brings a series of discomforts. Respiration depends on the lung, and dispersing fluids to the body surface also depends on it. The lung stores phlegm; when the lung is weak, phlegm easily accumulates into stubborn, fatal phlegm, worsening lung function—this is the root of respiratory disease, and one form of what Yumoto calls water toxin. Treating by reference to the Water Qi chapter of Jingui Yaolüe gives good results.
Fluids may be discharged through sweating, through purgation, and—in robust patients—even through emesis. The ancients treated asthma from lung cold with Lengxiao Wan using the emetic method. Thus, treating asthma and other respiratory disease may begin with the lung, spleen, and kidney, which govern body fluids; once water is drained and phlegm resolved, chest fullness and shortness of breath due to phlegm obstructing the upper burner are greatly relieved.
Impaired lung function also causes discordance between the nutritive and defensive qi, so sweat glands fail to sweat normally. Over time, constrained heat cannot vent, producing various macules and papules on the skin—this is the root of allergic skin disease and why many respiratory patients easily have itching. Treatment should focus on ventilating the lung to vent heat, or clearing the lung to vent heat.
Wind is the chief of the hundred pathogens. Allergic skin diseases such as urticaria often recur with attacks of wind pathogen. The Western concept of allergen closely resembles the TCM emphasis on wind and other external pathogens. I once saw a patient pass on a folk remedy: stewed winter melon with skin, used to treat urticaria. I tried it clinically and found it indeed works well on urticaria; moreover, it also works well for asthma due to water qi. From the TCM view, winter melon and winter melon peel promote urination and resolve phlegm, making them excellent for lung-system diseases caused by overflowing water.
It follows that attributing the source of allergic disease to the water toxin summarized by Yumoto and treating from the angle of promoting urination yields good results for many allergic respiratory and skin diseases.
Of course, the source of allergic disease—especially allergic skin disease—is not limited to water toxin. With prolonged illness, constrained heat transforms into heat toxin, which inevitably leads to blood toxin. Hence the ancients said: to treat wind, first treat blood; once blood moves, wind of itself ceases. When simple water-draining fails for allergic skin disease, adding a few blood-moving herbs improves the result.