Tang-kuei and Tribulus Combination
Danggui Yinzi is a formula that was designed to alleviate skin itching. The prescription is rarely mentioned in Chinese sources, but is widely appreciated by Japanese and Taiwanese practitioners. It is commonly presented in most countries in the form of dried extracts. The original form was a drink (yinzi).
The theoretical basis for this itchy skin condition in the Chinese medicine system is wind. Specifically, the problem arises because the blood is deficient and this allows wind to thrive in the unfilled meridians, the dried tissues, and spaces between the muscles. The wind can come from the exterior and it can be generated internally by the liver that is deficient in blood. We might interpret the ancient concept of external wind-as it applies to this case-in terms of skin irritants, such as allergenic substances that contact the skin or things eaten that produce a skin reaction. The concept of internal wind might correspond to generation of "stress hormones" that can contribute to inflammation, as occurs, for example, with neurogenic dermatitis (neurodermatitis). Blood deficiency might be interpreted here as corresponding to a lack of control over the generation of immune complexes involved in allergy or autoimmunity and substances that are related to stress reactions. Blood, which is a moist, yin substance, is attributed a controlling, calming action in the traditional Chinese system. The type of skin itching addressed by Danggui Yinzi, with blood deficiency and dryness, differs somewhat from that attributed to damp-heat syndrome, which corresponds to some cases of chronic eczema, such as those with "weeping sores." In that case, blood deficiency may also be present, but the dryness of blood is overwhelmed by the accumulation of dampness in the skin from other pathological factors (see the appendix).
The traditional concept that wind plays an important role in skin diseases is frequently manifested in the Chinese name for the diseases. Following is a list of some skin diseases that include the term wind (feng) in their name, as listed in the text Practical Traditional Chinese Dermatology (1):
Many of these skin disorders are characterized by itching, especially the various types of dermatitis, eczema, tinea, seborrhea, urticaria (fengtuan), and, of course, pruritis (a term for itching and burning sensation). Other skin disorders may not have the character for feng in their Chinese name, but are still considered to have wind as one of the etiologic factors. In addition to itching, wind disorders of the skin often involve production of scales.
Danggui Yinzi is based on therapies recorded by Zhu Danxi. The foundation of Danggui Yinzi is Siwu Tang (Tang-kuei Four Combination), a formula that Zhu favored for treating many ailments. Siwu Tang consists of tang-kuei, peony, cnidium, and rehmannia. Depending on the application, the formula may be made with red peony or white peony, and with either raw rehmannia or cooked rehmannia or a combination of the two. For Danggui Yinzi, white peony and raw rehmannia are traditionally used.
In the book of Danxi's teachings, Danxi Zhifa Xinyao (2), the chapter that covers formulas similar to Danggui Yinzi is the one devoted to laifeng. The concept of laifeng was popularized during the time of the Tang and Song Dynasties. It is a damaging wind that arises in the spring time, the season traditionally associated with wind and its pathogenic effects.
A poem titled the Dawn of Spring (by Meng Haoran; ca. 689-740 A.D.) mentions laifeng, in the context of hard wind and rain making the flowers fall:
In my spring slumber I felt not the dawn,
till I heard birds singing all around.
There was the clamor of wind and rain in the night.
How many petals lie strewn on the ground?
Laifeng is mentioned in another poem as the wind at dusk, also having a negative impact on spring flowers, as follows (by Li YŁ, 937-978 A.D.)
The red of the spring orchard has faded.
Far too soon!
The blame is often laid
on the chilling rain at dawn
and the wind at dusk.
The rouged tears
That intoxicate and hold in thrall-
When will they fall again?
As a river drifts toward the east
So painful life passes to its bitter end.
This wind adversely affects the skin and, in the field of medicine, the term laifeng (or, simply, lai) is often translated as "skin diseases" generally, or specifically referring to leprosy or scabies. The character for lai is different than that used in the poems, but the pronunciation is the same and its origins similar.
There is little discussion of the subject of laifeng in Zhu's book, other than the recommendations for treatment. In the laifeng chapter, itching of the upper body due to deficiency of blood is to be treated by Siwu Tang with scute and spirodela (herbs used for clearing heat). Danggui Yinzi (not specifically mentioned in this section of the book) has additional tonics and wind-resolving herbs.
Siwu Tang is selected to nourish the blood to calm wind following the ancient idea: "To treat wind, first treat the blood; when the blood is full, the wind will naturally be extinguished." In Siwu Tang, two of the herbs are reputed to specifically aid dispelling wind: tang-kuei and cnidium which, unlike peony and rehmannia, have volatile oils commonly encountered in herbs for dispelling external wind (these two herbs are botanically related to the wind-dispelling herbs angelica, siler, chiang-huo, and tu-huo, with similar aromatic components).
The blood nourishing and wind-dispelling aspects of Siwu Tang are complemented in Danggui Yinzi by ho-shou-wu, an herb especially used for calming internal wind. To this base, three other herbs specific for resolving wind syndromes are added: siler, schizonepeta, and tribulus. In the modern Materia Medica, tribulus is classified as an herb for internal wind, while the others are for external wind, but in Zhu Danxi's time, the separation between internal and external wind had not been made. Originally, it was understood that internal and external wind could intermingle, one reinforcing the other, and cause various symptoms. Tribulus was considered an important herb for dispelling external wind.
The complete Danggui Yinzi formula is:
According to the Chinese interpretation, when skin lesions do not heal quickly, this indicates that both the qi and blood are deficient. The inclusion of astragalus and licorice with the blood nourishing herbs helps to boost the qi for more quickly nourishing the blood and more rapidly healing the skin. Further, when using wind-dispelling herbs, such as siler and schizonepeta, there is a concern that those who suffer from deficiency will experience increased perspiration and further loss of essential fluid and drying of the blood. Therefore, herbs that astringe sweating, such as astragalus and peony, are included. These herbs are used in other famous surface-regulating formulas, such as Jade Screen Formula (with astragalus counterbalancing siler) and Cinnamon Combination (with peony counterbalancing cinnamon twig). The principles of therapy here are applicable to other allergic-type surface reactions. For example, the formula has been applied (with claimed success) in treating allergic rhinitis.
Itching that is accompanied by a hot, burning sensation and/or reddening of the skin, may be treated by variants of Danggui Yinzi that incorporate herbs for dispelling heat, such as scute, sophora, or gypsum. An example is Xiaofeng San, which is described in the appendix.
A formula with indications similar to those for Danggui Yinzi for treatment of itching skin is Xiaofeng San (Tang-kuei and Arctium Formula). The prescription is indicated for cases where there is a complication of heat, either as a relatively dry wind-heat syndrome or the moister form of damp-heat.
Xiaofeng San (xiao = reduce or dispel; feng = wind; san = powder) is a better known formula than Danggui Yinzi, and was produced as a variant of it. The prescription is mentioned in Waike Zhengzong (True Lineage of External Medicine) by Chen Shigong (1617), a famous Chinese surgeon and ethicist. For nourishing blood, his formula has tang-kuei and rehmannia in common with Danggui Yinzi, but in place of ho-shou-wu, this formula includes black sesame as an additional blood tonic. For dispelling wind, the formula includes schizonepeta and siler in common with Danggui Yinzi, but includes arctium and cicada (classified as herbs for wind-heat) rather than tribulus. In place of astragalus and licorice, this formula includes red atractylodes (to resolve damp) with licorice (used here to help eliminate toxins). The remainder of the formula is comprised of herbs for clearing heat and for drying damp: sophora, akebia, gypsum, and anemarrhena.
Because of its emphasis on clearing heat and damp, Xiaofeng San is better suited for short term use in resolving these pathologic factors, and can then be followed up by Danggui Yinzi as a tonic that still addresses the residual skin irritation and itching. Danggui Yinzi may then be taken over an extended period to assure complete resolution of the skin problem.
The complete Xiaofeng San formula is:
This formula is appropriate for treatment of weeping eczema or contact dermatitis (e.g., poison oak) with severe itching. It may be combined with Danggui Yinzi for cases involving greater deficiency of blood. Veterinarians trained in Chinese medicine often prescribe these formulas for dogs who suffer from a variety of serious skin ailments.
Topical therapies are also considered valuable for the heat-type skin ailments. Chen Shigong developed an ointment called Ziyun Gao (Purple Clouds Ointment). The formula was later modified in Japan by Seishu Hanaoka (1760-1835), who developed the field of surgery in Japan and integrated traditional Chinese medicine with Western medicine (brought by Dutch settlers). The ointment was marketed in Japan and Taiwan after the Second World War, and later, to many other countries. The purple root that gives the ointment its color and name is either Arnebia euchroma or Lithospermum erythrorhizon, two closely related herbs of the Borage family that have similar roots used interchangeably (these herbs are known in Chinese as zigen, purple root). The root has antiseptic and anti-inflammatory action, and it promotes healthy blood circulation. The other standard ingredient is tang-kuei, while other ingredients vary somewhat according to the manufacturer; they usually have a base of sesame oil. A similar formulation-Yu Hong Gao (Jade Red Ointment)-was developed during the Qing Dynasty and reported by Wu Qian in his book Golden Mirror of the Medical Tradition (Yizong Jinjian, 1742). It also has arnebia or lithospermum along with tang-kuei as main ingredients in a base of sesame oil.