Alopecia Areata in Chinese Medicine: Blood Deficiency vs. Kidney Deficiency — Two Distinct Mechanisms Behind Hair Loss

In daily life, some people suddenly notice smooth, bald patches on the scalp with clear borders, neither itchy nor painful. Folklore calls it "ghost shaving," while traditional Chinese medicine (TCM) refers to it as "oil wind" (yóu fēng). Although the outward manifestation is the same—hair falling out in patchy, bald areas—some patients present with a sallow complexion and pale lips and nails, while others experience soreness and weakness in the lower back and knees, along with frequent nocturia. The underlying mechanisms differ: one is blood deficiency generating wind, and the other is insufficiency of kidney essence. What distinguishes them? In the former, the "raw materials" for nourishment are insufficient; in the latter, the foundation that stores "primordial qi" is shaken. If one fails to differentiate deficiency from excess and blindly takes tonics, the result may actually add further disturbance to the body.

The *Orthodox Manual of External Medicine* (*Waike Zhengzong*) states: "In oil wind, blood deficiency prevents the qi from nourishing the skin and flesh, so the hair roots become empty and fall out in patches." This highlights the central role of blood deficiency in alopecia areata. However, in clinical practice, pure blood deficiency is rare; most cases are complicated by kidney deficiency or liver qi stagnation. Why can hair falling out in patchy bald spots not be simply attributed to "staying up late" or "stress"? Because hair growth depends on the nourishment of liver blood and the transformation of kidney essence. The liver stores blood, and hair is the surplus of blood; the kidney stores essence, and its luster manifests in the hair. Blood and essence—one yin and one yang, one soft and one firm—jointly sustain the vitality of hair follicles. To look only at the surface-level hair loss while ignoring the underlying visceral imbalance is to see the trees but miss the forest.

This raises the question: when hair falls out in patchy bald areas, how can one distinguish between blood deficiency and kidney deficiency?

The key lies in the accompanying overall state. In blood deficiency, the cause is often prolonged excessive rumination that silently consumes yin blood, or weakness of the spleen and stomach with insufficient sources of generation. Typical signs include a pale complexion, dizziness and blurred vision, palpitations and insomnia, brittle nails, and in women, scanty and pale menstrual flow. The tongue is often pale with thin white coating, and the pulse is thin and weak. Hair loss in such individuals usually has a gradual onset; the skin at the edges of the bald patches appears pale and feels soft. In kidney deficiency, on the other hand, the cause may be congenital insufficiency, excessive sexual activity damaging the kidney, or aging. It is often accompanied by soreness and weakness of the lower back and knees, tinnitus or deafness, copious clear urine at night, and memory decline. The tongue is often pale and swollen with teeth marks, and the pulse is deep and thin. Hair loss in these cases may be accompanied by dry, lusterless hair, and even thinning of the eyebrows and axillary hair, with the skin around the bald patches tending to be dry.

Both blood deficiency and kidney deficiency manifest as patchy hair loss, but one operates at the level of blood and the other at the level of essence. Blood deficiency reflects "inadequate nourishment," while kidney deficiency reflects "a shaken foundation." In terms of treatment direction, blood deficiency is best addressed by strengthening the spleen and nourishing blood so that qi and blood have a source of generation; kidney deficiency is best addressed by replenishing essence and tonifying the kidney so that the foundation is stabilized. If one fails to identify the primary pattern and indiscriminately uses kidney-tonifying agents, the patient with blood deficiency may suffer from cloying, stomach-dampening effects that hinder the production of qi and blood. Conversely, if blood-nourishing herbs are used alone for kidney deficiency, they are like trying to put out a burning cartload of firewood with a cup of water—ineffective and unable to reach the root. Clinically, these two states often intertwine, with one predominating; a licensed TCM practitioner must make a comprehensive judgment through tongue and pulse examination.

Going deeper: why does blood deficiency cause patchy bald spots rather than uniform thinning?

This involves the TCM understanding of "wind." When blood deficiency persists, the blood vessels are not fully filled, and deficient wind arises internally. Wind is characterized by swift movement and frequent change; it is dry and harsh in nature, capable of carrying deficient fire upward to harass the scalp. The *Golden Mirror of Medicine* (*Yizong Jinjian*) explains this mechanism as follows: "Because the pores are open, pathogenic wind takes advantage of the deficiency to invade, causing wind excess to dry the blood, which then fails to nourish the hair." Wind is by nature wandering and unfixed, which is why the bald patches are often round or oval with clear borders, appearing here and there in succession. In other words, the patchy distribution of alopecia areata is a fingerprint-like piece of evidence for wind pathogen activity. If there were only blood deficiency without wind movement, hair loss would typically present as diffuse thinning rather than patchy shedding.

Where does wind come from? In addition to blood deficiency generating wind, there is also liver qi stagnation transforming into wind. When emotions are frustrated, with depression or anger, liver qi becomes constrained, constraint transforms into fire, and exuberant fire generates wind. Wind and fire fan each other upward to disturb the vertex of the head. In such individuals, prior to the patchy hair loss, there is often a distinct emotional disturbance or a prolonged state of high pressure and anxiety, accompanied by hypochondriac distension and pain, a bitter taste and dry throat, irritability, and a red-edged tongue with a wiry, thin pulse. The difference between liver wind and blood-deficiency wind is that liver wind is predominantly excess, while blood-deficiency wind is predominantly deficiency; liver wind is usually triggered by emotions, whereas blood-deficiency wind often coexists with abnormal complexion and menstrual changes. In clinical practice, many cases of alopecia areata present with "mixed deficiency and excess"—the excess manifestation of liver qi transforming into wind coexists with the deficiency foundation of blood failing to nourish. Treating only the liver or only the blood is seldom comprehensive enough.

This leads to a third question: what role does kidney deficiency play in patchy hair loss?

The kidney stores essence; essence generates marrow; marrow nourishes the bones; and the luster of the kidney manifests in the hair. Kidney essence is the root of prenatal constitution—the deep well of life's energy. Between liver blood and kidney essence exists a relationship of "mutual generation of essence and blood"—kidney essence can transform into liver blood, and liver blood can nourish kidney essence. If kidney essence is depleted, there is no source to transform blood, and liver blood becomes insufficient as well. Conversely, excessive consumption of liver blood will inevitably impair kidney essence over time. This is why many people with long-standing blood deficiency shift from "diffuse thinning" to "patchy baldness" after middle age, accompanied by lower back and knee soreness, memory decline, and other signs of kidney deficiency. At this stage, both essence and blood are depleted; the hair root resembles a tree with loose, thin soil around its roots—when any wind or rain comes, it is uprooted entirely.

Clinically, typical severe alopecia areata (including alopecia totalis and alopecia universalis) is often closely related to kidney deficiency. When kidney essence is exhausted, not only does the scalp hair fall out in patches, but even the eyebrows and vellus hair struggle to grow. Such patients typically have a thin, small tongue body with peeling or glossy red tongue coating at the root, and a deep, thin, weak pulse, especially at the chi position. Treatment is not a matter of a single day; it requires slow, gradual restoration. In adolescents with sudden onset alopecia areata, if accompanied by night sweats, hotness in the palms and soles, and a red tongue with scanty coating, the pattern is usually kidney yin deficiency with deficient fire flaming upward, scorching the hair roots. In such cases, one should not blindly use tonics upon seeing hair loss; instead, sweet and cool moistening agents are needed to nourish water and enrich wood, thereby subduing the deficient fire.

Understanding the distinct pathways of blood deficiency and kidney deficiency makes it clear that patchy hair loss is not an isolated event of the scalp—it is a letter from the internal organs.

I. Blood-Deficiency Hair Loss: The Interlocking Chain of the Spleen, Stomach, and Liver Blood

The spleen and stomach are the foundation of acquired constitution and the source of qi and blood generation. Irregular diet, excessive rumination, and prolonged illness with inadequate recovery can all impair the spleen and stomach. When the spleen and stomach lose their transporting and transforming power, the essence of water and grain cannot be converted into qi and blood. Liver blood has no source, and the hair roots lose their nourishment. In addition to lax and pale scalp in the bald areas, such individuals often experience abdominal distension after meals, loose stools, and a bland taste in the mouth. The tongue is pale and swollen with teeth marks, and the pulse is soft and weak. This is a pattern of root deficiency with the branch manifestation of blood deficiency and wind movement.

Interestingly, this type of hair loss is more common in middle-aged women. They often juggle multiple roles, worry and overthink, and skip proper meals. Over time, the qi of the spleen and stomach is quietly depleted, and the supply of qi and blood essence falls short of demand. Hair is the "surplus of blood." When essence and blood are insufficient, the body prioritizes the viscera and discards the skin and hair—making hair the first "non-essential asset" to be sacrificed. For these women, patchy bald spots are the body's signal to "slow down and eat properly."

1. Spleen and stomach weakness with no source for qi and blood generation

When the spleen and stomach's transporting and transforming function declines, even a normal diet cannot be efficiently converted into usable qi and blood. Blindly consuming cloying blood-nourishing products such as donkey-hide gelatin (ejiao) or prepared rehmannia (shudihuang) at this stage will only obstruct the stomach and aggravate bloating and loose stools. Clinically, such patients should first nourish and protect the spleen and stomach. Only after the transporting function recovers can blood tonification be considered. Otherwise, what is supplemented is not qi and blood but stagnant damp turbidity.

2. Liver blood insufficiency with wind pathogen taking advantage of deficiency

The liver stores blood, and its substance is yin while its function is yang. When liver blood is insufficient, the Jueyin wind-wood qi loses its nourishment and rises into wind. Wind tends to ascend, directly attacking the vertex, shaking the hair roots. This type of hair loss is often accompanied by dry eyes, blurred vision, numbness of the limbs, and brittle nails. In women, reduced menstrual volume and delayed cycles may also occur. The principle "to treat wind, first treat blood; when blood moves, wind is extinguished by itself" points precisely to the strategy of nourishing blood to calm wind.

II. Kidney Essence Not Secured: Hair Is the Splendor of the Kidney, and the Depth of Its Root Depends on the Kidney

Patchy hair loss caused by kidney essence depletion commonly appears in three groups: those with congenital insufficiency, those with excessive sexual activity, and those with prolonged illness that eventually reaches the kidney. Kidney essence is like a well. When the well is full, the hair roots are moistened; when the well runs dry, the hair roots become withered and break off at the slightest pull. Hair loss in this group often develops slowly, but once established, it covers a wide area and is difficult to recover from. The accompanying symptoms are crucial: soreness and weakness of the lower back and knees, heel pain, frequent nocturia, tinnitus resembling cicada sounds, and decreased sexual function.

1. Kidney yin deficiency with deficient fire scorching the hair

When kidney yin is insufficient, water cannot control fire, deficient fire floats upward, and scorches the hair roots. In this state, the scalp in the bald areas is slightly reddened, accompanied by dry mouth and throat, heat in the five centers (palms, soles, and chest), night sweats, and insomnia with dream-disturbed sleep. The tongue is red with scanty coating and cracks, and the pulse is thin and rapid. This pattern indicates that essence, blood, and body fluids are being consumed in large amounts, requiring a strategy centered on "supplementing water." In daily diet, dark-colored foods such as black sesame, mulberry, and black beans are mild in nature and provide some nourishment for kidney yin. However, if the body has significant damp-heat, these foods may also promote dampness and obstruct the stomach, so their use must vary according to individual constitution.

2. Kidney yang insufficiency with loss of warming function

This pattern is more commonly seen in severe alopecia areata. Kidney yang is the root of yang qi for the entire body. When yang is deficient, the four extremities are not warmed, the hair pores lose their ability to open and close, cold congeals and blood stasis occurs, and the hair roots cannot be nourished. Manifestations include fear of cold and cold limbs, listlessness, copious clear urine at night, cold pain in the lower back and spine, impotence and premature ejaculation in men, and uterine cold with infertility in women. The tongue is pale, swollen, and tender with a white slippery coating; the pulse is deep, slow, and weak. When yang qi is deficient, the propulsion of qi and blood is weakened, and the local microcirculation of the scalp is in an "idle" state. In such an environment, hair roots are like vegetation in a high-altitude cold zone—difficult to survive.

Differentiated Nourishment for Daily Life: How to Look for Clues When Hair Falls Out in Patchy Bald Spots?

To distinguish blood deficiency from kidney deficiency, in addition to observing accompanying symptoms, one can also inspect a detail: the state of the skin in the bald areas. With blood deficiency and wind movement, the scalp in the affected area tends to be pale and thin, soft to the touch, with blurred borders; there may be multiple bald patches of varying sizes appearing one after another. With kidney essence insufficiency, the scalp in the affected area tends to be dry and tight, with clearly defined borders; the area of hair loss is often larger and may even merge into extensive patches. In addition, the pulse in blood deficiency is often thin and weak, fading on deep pressure; in kidney deficiency, the pulse is often deep and thin, especially at the chi position (which corresponds to the kidney). On the tongue, blood deficiency tends toward pallor, while kidney deficiency tends toward dryness, thinness, or puffiness.

The purpose of self-observation is not to replace a physician's diagnosis, but to learn to perceive the body's language. For example, before the bald patch appears, has there been several consecutive days of poor sleep? Did the stools suddenly become loose? Has lower back soreness worsened? These clues can help a licensed TCM practitioner more accurately assess the current state of deficiency and excess in the viscera. Ancient TCM texts state: "By observing the luster or dryness of the hair, one can discern the deficiency or excess of the viscera." The flourishing or withering of the skin and hair reflects the ebb and flow of qi and blood in the internal organs. Rather than anxiously staring at the blank patch, it is better to look down at your nails, complexion, sleep, and emotions—every detail of the body is delivering a letter.

In terms of diet, whether the tendency is toward blood deficiency or kidney deficiency, nutritional balance should be ensured, with moderate intake of foods rich in protein and B vitamins. From the perspective of TCM health preservation, the regulation of daily rhythm is more important than what one eats. The night hours are when the liver meridian is in command; when a person lies down, blood returns to the liver. Chronic sleep deprivation is equivalent to forcibly interrupting the liver blood's repair window—no amount of blood-nourishing food can offset that loss. Emotional regulation is equally indispensable; anxiety and rumination both silently consume yin blood and disturb liver wind. It is advisable to leave oneself a moment of emptiness, allowing the qi mechanism room to unfold. As for exercise and guided movement, moderate soothing exercise helps qi and blood circulate, but it should be tailored to one's capacity and avoid profuse sweating, which could further damage qi and yin. Whether it is dietary therapy, daily routine, or exercise, it is recommended that arrangements be made dialectically according to individual constitution under the guidance of a licensed TCM practitioner.

Have you ever had the feeling that physical discomfort is often the result of years of accumulation, rather than a mistake made in a single moment? Patchy bald spots may be the body's reminder that the two storehouses—blood and essence—have quietly turned on their yellow warning lights. Perhaps take a moment to reflect: lately, have you been eating properly? Are you still staring at a screen late into the night? Has it been a long time since you sat quietly and looked at yourself?

References:

1. Traditional Chinese Medicine Ancient Literature Database (including the *Waike Zhengzong* and *Yizong Jinjian* for original text consultation): https://tcmdata.cintcm.com/

2. World Health Organization strategy document on traditional medicine: https://www.who.int/health-topics/traditional-complementary-and-integrative-medicine

3. Official website of the National Administration of Traditional Chinese Medicine: https://www.satcm.gov.cn/

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