Etiological analysis of chloasma from view of Western and Chinese traditional medicine

Wen-Ming Cao,Jing Zhao,Xia Wang,Xin-Liang He, Na Yu＊

1Changle People's Hospital of Shandong Province, Shandong, China.2Weifang Traditional Chinese Hospital of Shandong Province, Shandong, China. 3Dezhou Hospital of Traditional Chinese Medicine, No. 461 Dongfanghong Road, Decheng District, Dezhou 253000, China. 4Shandong Provincial Third Hospital, No. 12 Wuyingshan Central Road, Tianqiao District,Jinan 250000,China.

＊Corresponding to:Wen-Ming Cao,Email:caowenming1983@126.com;Na Yu,Email:15866560197@163.com.

Abstract

Keywords:Chloasma,Etiology,Western medicine,Traditional Chinese medicine

Introduction

Chloasma is a discosmetic dermatosis in which pigment is deposited on the face, cheeks, forehead and other parts due to the pigment metabolism disorder. It is manifested as facial yellow-brown patches [1], with different shades, different shapes, and often symmetrically distributed. The disease mostly occurs in women of childbearing age, but also in men. The prevalence rate of chloasma is still increasing year by year, which reflects the physical and mental health of women. This paper discusses the etiology of chloasma from modern medicine and traditional Chinese medicine.

Research on etiology of chloasma in western medicine

Chloasma is a common and refractory skin disease.Under normal physiological conditions,melanocytes in the skin contain characteristic melanosomes, while tyrosinase can trigger the synthesis of melanin. And tyrosinase forms dopa by oxidation, but dopa is not only derived from the oxidation of melanin, and its occurrence and development may be related to the following factors.

Endocrine dyscrasia

Endocrine dyscrasia is the main cause of chloasma,and the estrogen can accelerate the synthesis of melanocytes. Some studies [2] have shown that the estradiol production dose is dependent on the tyrosinase activity, increasing the direct biological effects on normal melanocytes. Estrogen [3] can relieve the blocking effect of building substrate on tyrosinase and increase the content of melanosomes in the skin. And progesterone can obviously promote the transport and diffusion of melanosomes. Handel et al.has found that oral contraceptives and pregnancy are the obvious causes of chloasma in a case-control study on the risk factors of chloasma[4-5].Lutfi RJ et al.[6]has found that the incidence of thyroid disease in patients with this disease is 4 times that of normal adults; while Xie Zhijie [7] has discovered that the levels of T4 and FT4 in serum of patients with this disease are significantly higher than those of normal population.

Oxygen free radical

Under normal circumstances, the synthesis and clearance of oxygen free radicals in human body is in a dynamic balance state. In patients with chloasma, the production of oxygen free radicals increases and the clearance decreases. The accumulation of harmful substances such as peroxides in the body can directly damage the structure of cells to promote the formation of pigments, and then chloasma is hereby induced. Yi Yunlian et al.[8] has determined the contents of superoxide dismutase (SOD) and malondialdehyde(MDA) in the serum of patients with this disease. The results has shown that the content of MDA in serum of patients with this disease is significantly higher than that of normal people, while the content of SOD is significantly decreased. Xie Mingfeng [9] has also conducted relevant studies on the SOD and MDA in serum and found the same findings when using self-simulated pearl Sibai cream to treat this disease,which has again confirmed that the increased content of oxygen free radical is the important reason for the formation of this disease.

Hemorheology

Modern medical research showed [10] that the occurrence of chloasma is closely related to hemorheology.In women with chloasma,the results of the hemorheology test usually show increased blood viscosity and decreased levels of SOD leading to a disordered balance between oxides and antioxidants.The experiment has confirmed that hemorheology in patients with chloasmais significantly different from that in normal contrast group.

Ultraviolet ray

The effect of ultraviolet ray irradiation on the pathogenesis of chloasma is mainly related to the long-term ultraviolet ray irradiation stimulating melanocytes in the skin, which can promote their division and proliferation to increase the synthesis of melanin particles. Ultraviolet ray irradiation can increase the content of tyrosinase in melanocytes,which induce the synthesis of melanin, regulate the synthesis process,and aggravate the pigmentation[11].

Heredity

Chloasma is more common in Eastern Indochina and Latin American ancestry, and heredity and ethnic factors are widely recognized. Ortonne et al. [12] has confirmed Miot LD's view through investigation and research. He has investigated 324 patients with chloasma and found that patients with a family history of chloasma accounts for 48% of the total number.Based on the related risk factors analysis of chloasma patients,it showed that there were 60 cases of heredity tendency,accounting for 30.0%of the total number.

Mental factors

The patients with chloasma often have inferiority,depression,anxiety and other negative emotions due to chloasma on the faces, and these negative emotions can in-turn affect and aggravate the condition of patients [13]. The onset and aggravation of chloasma are inseparable from mental factors. Most scholars believe that the mechanism may be that mental stimulation stimulate the hypothalamus pituitary adrenal axis and release a large number of neuropeptides, such as melanocyte stimulating hormone. These neuropeptides have a significant impact on the biological characteristics of melanocytes and promote melanocytes to secrete melanin[14].

Drugs and cosmetics

Long-term oral contraceptives can cause hormonal disorder and trigger chloasma. Chronic oral administration of sedatives and spironolactone can also induce chloasma. The use of cosmetics can also make it induced, and it may be related to the direct stimulation or allergic reactions of certain ingredients of cosmetics, such as linoleic acid, metal substances,preservatives,etc.

Disease

Chloasma usually occurs in patients with liver disease,lung disease, malignant tumor, endocrine disease and some autoimmune diseases, which may be related to the disorder of pituitary-endocrine axis.

Alteration of intestinal flora

The alteration of intestinal flora affects the metabolism and immune defense of nutrients. In the endocrine and circulatory systems, the disordered intestinal flora participates in a series of oxidation reactions to induce the pigmentation of skin.

The etiology of chloasma in traditional Chinese medicine(TCM)

According to the Huangdi Neijing, the fundamental cause of this disease comes to women’s deficiency of kidney Yin, dysfunctional organs, derangement Qi and blood and Chong-Ren meridian dysfunction. From the description in the Plain Questions: Vessels and meridians are known widely distributing around in the twelve skin zones. Since being the most superficial of human body, they are preferential accesses for viral pathogens to invade into the body.After their intrusion,the viral pathogens dwell in internal organs, flow through meridian vessels, trigger off diseases and develop into disease spots. The ancient book Peaceful Holy Benevolent Prescription pinpoints the conditions of the viscera and twelve meridians will all be reflected on the face. Besides, as mentioned in The Golden Mirror of Medicine: The blackish facial patch of chloasma appears to be dirt and dust on the face at the outset but later, develops to be as dark as coal; it is resulted from deep worries and depression. The internal conditions of human body will definitely be embodied on the outer skin. Traditional Chinese medicine ascribes chloasma to the dysfunction of the viscera. The stagnation of Qi and depression of the liver, the deficiency of the kidney-Yin, and the weakness of the spleen and the stomach can all lead to Qi-blood disharmony and blocking of blood vessels.They then prevent the face and other parts of the appearance being nourished by Qi and blood, thereby resulting in the incidence of chloasma [15]. Clinically,most of the onsets of chloasma stem from the disharmony between the functions of multiple internal organs and their unpleasant interactions. The disorder of the lungs, spleen, liver and kidney brings about the stasis and stagnation of Qi and blood, the sluggish acerbity of meridians, and Chong-Ren imbalance.Then, the dampness, turbidity and stasis of blood start to present in the skin, of which the part on the face grows into chloasma.

The relation between the incidence of chloasma and the disorder of the viscera

Disorder of the lungs.According to the theory of TCM, the physiology and pathology of the lungs tightly correlate with the function of the skin and the condition of the hair. That is, the lungs share an interacting relationship with the skin; they interwove with each other. The lungs are thought of the manager of Qi, regulating breath. They inhale fresh air and exhale turbid air, supplying oxygen for the entire body including the skin so as to maintain its vitality. Also,the lungs govern dispersion. They disperse defensive Qi and body fluid to the skin and hair orifices, making the skin delicate and moist and sustaining its barrier,excretion and other functions. If the lung Qi or lung Yin is insufficient, or the lungs are under the attack by evil pathogens or in the state of phlegm-damp accumulation, the lungs may be left out of function of dispersing. This can cause dryness and roughness in the skin, as well as occlusion of hair orifices. Eminent TCM physician Zhong Yize and Chen Mingling hold the idea that the lungs are the canopy of other viscera,locating at the upper Jiao. They can deliver body fluid and essence to the skin, hair and muscle, as fogs and dews irrigate the land. Therefore, to a certain extent,the brightness and dullness of the skin are related to the strength of lung Qi. The deviation of the lung Qi off the regular dispersing pattern, the fault transferring and distribution of body fluid, and the accumulation of dampness in the skin and hair will grow into heat-transmission which will then leave the skin dark and gloomy[16].

Disorder of the spleen.The spleen governs transportation and transformation and controls over blood. Besides, it is the main site where human body digests and absorbs the food and water taken in. The spleen provides material basis for the progression of body vital movements and for the generation and transformation of essence,blood and body fluid.Those functions merit it as “the source of acquired constitution of human body”. What is more, the ascending action of the spleen delivers the essence and fluid of water and food absorbed upward to the heart and the lungs. Those essences are then transformed by the heart heat into blood to nourish the full body.

Disorder of the liver.The liver takes in charge of storing blood and releasing stagnated energy. It is capable of storing and regulating blood and normalizing the functional activities of Qi. Not merely,the liver can also promote the delivery and distribution of blood and body fluid, keeping Qi and blood in harmony, filling meridian and vessels with blood, as well as nourishing the skin,hair and muscle with blood.According to the Zhang’s Comprehensive Medicine[17], if the liver Qi is not full, or the liver loses its flourishment, the color of chloasma patches will be evident. This preliminarily reveals the relationship between the liver and chloasma. Yin in property and Yang in function, the liver naturally prefers ease of mind, thus able to adjust the movement of vital energy and regulate the mood. Its dispersion can be impacted by the impairment by mood, deficient nurturing due to long illness, and the implication by lesions of the kidney organ and uterine organ. If so, Qi will move in a bumpy way, then stagnate and transform into heat.Subsequently,the heat evil will be burnt in the face and manifested as blackish patches. For this reason, the patients with chloasma are frequently accompanied with such negative emotions as anxiety and depression in clinical. Those negative emotions will, in turn,aggravate the illness of chloasma.So,a vicious cycle is formed[18].

Disorder of the kidney.The primary physiological function of the kidney falls into its governance of storing essence, the material foundation of all vital activities of human body. Also, since the essence stored in the kidney mainly are the innate essence; the kidney is merited as“the congenital foundation”.

The essence stored in the kidney can be transformed into kidney Qi which consists of kidney Yang and kidney Yin. The kidney essence and kidney Yin undertake the function to moisturize the skin while the kidney Qi and kidney Yang to warm the skin.With the failing of the kidney in function, the body and skin ages in a rapid manner. The ancient book Miraculous Pivot recorded the patient with kidney diseases show dark complexion and cheekbones. It discloses the tight relation between the onset of chloasma and the kidney.Mostly,chloasma occurs in women at the childbearing age, prompting that those women start to show deficiency in kidney Qi and decline in blood and Qi.

The relation between the incidence of chloasma and the meridians,Qi and blood.

The meridians belong to the viscera. They externally connect with the body surface and work as the channels through which Qi and blood move. Often,the lesion in the internal organs could be embodied in the skin surface. The head is the confluence of all Yang-channels, across which the three Yang meridians of feet and hands extend. Therefore, once discordance takes place between the meridians, diseases occur more in the face. Since chloasma is preferentially manifested in the face, its incidence and development is closely relevant with meridians. The Yellow Emperor’s Canon of Internal Medicine-Miraculous Pivot-Meridians and Collaterals [19] revealed the relation between the lesion of the liver meridian of Foot-Jue Yin and the onset of chloasma.Gao Jing et al.[20] explored the physiological condition of Yang brightness and pulse weakness of women in perimenopausal period and put forward a point of view as to prevent and treat chloasma by ameliorating the“bright Yang and deficient fluid and Qi” of patients.The majority of chloasma onsets lies in the lesion of Jueyin meridian and Yangming meridian in terms of the differentiation of meridians. TCM believes disharmonious, astringent or turbid Qi and blood cannot nourish the skin, thus bringing about “black anhydride” or “blackish patches in the face due to blood stasis”. It can be concluded thereupon that deficient Qi and blood or stagnated Qi and blood is closely related to the onset of chloasma.

The relation between the incidence of chloasma and Chong-Ren meridians.

Chong Channel and Ren Channel are two special meridians in the human meridian system, both of which belong to the eight extra-meridian channels.Originating from the cell, Chong Channel works to regulate the Qi and blood of twelve meridians and Ren Channel to regulate the Qi and blood of Yin meridians.Both channels play an important role in menstruation and pregnant function of women. When the Qi and blood of Chong and Ren channels are insufficient or move in a bumpy way, women frequently present irregular menstruation, metrorrhagia, amenorrhea or infertility. Chloasma more occurs in women at childbearing age or who have a history of pregnancy,gynecological diseases and irregular menstruation.Therefore, the onset of chloasma is linked with the disorder of Chong and Ren channels. In light of the viewpoint of Palumh A[21], many facial skin diseases in women are closely related to Chong and Ren channels, and the treatment for chloasma with depressed liver and deficient blood should be formulated with Ligustrum lucidum and Eclipta to condition the two channels.

Never has TCM and Western Medicine discontinued their research on chloasma. With the advancement of modern cosmetic medicine technology, a host of therapies for chloasma come into being. Compared with single treatment which holds such inferiorities as to induce pigmentation, recurrence of chloasma and poor clinical effect. Multi-treatment combined therapy have the potential to improve the curative effect,shorten the course of disease and reduce adverse reactions;it is thus recognized the main method to treat chloasma at present.