Eczema is a kind of common allergic inflammatory dermatosis. It is divided into three kinds :acute, subacute and chronic. Its clinical characteristics are itching on the affected part, the polymorphic skin lesion and frequent recurrences. It can attack people, male or female, at any age and any part of the body.
Pathogenesis and Pathophysiology
Eczema is called jin yin chuang (suppurative ulcerous lesion) in the classics. The six external evils are external causes and spleen dampness is its primary internal cause. Blood heat and wind heat are secondary causes. Spleen dampness is a morbid state marked by accumulation or retention of water, Dampness or Phlegm due to decline or disturbance of the Spleen’s transforming and transporting effects. as it is mostly caused by spleen deficiency, it is also known as Spleen deficiency producing Dampness.
Generation of endogenous Dampness is usually caused by over-weight with excessive Phlegm or Dampness, over intake of raw and cold food or greasy and fatty food impairing the Spleen and the Stomach which leads to failure of the Spleen to transform and transport, disturbing the water metabolism, failure of water to be transformed and the ensuing production of Dampness, Phlegm, retained fluid or edema. Failure of the Spleen to transform and transport is the main factor contributing to formation of the endogenous Dampness, and the transforming and transporting effect of the Spleen depends on the warming and steaming effects of the Kidney Yang, so transformation of the endogenous Dampness is also closely related to the Kidney.
Transformation of Body fluid into sweat mainly depends on the dispersive effect of the Lung Qi, while that into urine on the steaming effect of the Kidney. Thus, functional decline of the Lung or Kidney, especially that of the Kidney, serves as the main cause of the retention of water.
As an allergic dematitis, the specific allergen (according to modern western medicine) is hard to identify. However, it is believed that certain foods, intestinal parasites, infectious lesions, and spontaneous sensitivity or even cold weather, wind, heat, sunlight, and certain plants can cause this condition. Eczema may also be related to the individual constitution and functional impairment of the nervous system.
Causes of Eczema
- External stimulus – sunlight, ultraviolet rays, cold, heat, dryness, excessive perspiration, abrasion, animal fur, plant or chemical substances) and other common household items (cosmetics, soap, etc)
- Internal stimulus – retarded digestive system, obstructed intestinal mechanism, stress, insomnia, excessive labour, drastic emotional influences, impeded metabolism, internal imbalance)
Individuals with eczema or damp heat related skin conditions are to avoid beef, mutton, seafood, including fish, spicy foods and alcohol. These food substances may cause flare ups of the eczema. Over eating and over drinking, or intake of excessive food constantly will exceed the digesting and absorbing ability of the Spleen, causing food retention and impairment of the Spleen and the Stomach.
Since the infant’s Spleen and Stomach are weaker than the adult’s, such diseases affect the infants frequently. Long term stagnancy of food in the body may transform into Heat, and impairment by cold or cool food may cause accumulation of Dampness. Excessive Dampness will result in the liquid being steamed up to the surface of the skin.
- Acute Eczema | Jin Yin Chuang: Acute eczema tend to appear abruptly and systematically on the interior aspects of the four extremities, such as at the cubital and popliteal fossae. It may also affect the face and neck, the dorsal aspect of the hands and feet, and the scrotum. Its manifestations are multiform: erythema, papules, watery blisters, pustules, suppurative ulcerations, and scabs. Two or three or even more of the above signs may present simultaneously. However, the border of the affected area is always indistinct. There may also be paroxysms of itching.
- Chronic Eczema | Jin Yin Chuang: Chronic eczema may either develop from acute eczema or it may develop by itself. It is also characterized by rough, thickened skin, lichenification, desquamation, and pigment sedimentation with a distinct border. The patient often complains of severe itching. There may be frequent acute flare-ups on any part of the body; although the most commonly affected areas are the face, retroauricular region, the scrotum, and the shanks. Symptoms falling between acute and chronic forms are call subacute eczema.
- Aural Eczema | Er Bu Shi Zheng: Extensive erythema may appear in the creases behind the ears or spread over the retro-auricular area. Exfoliation, suppurative ulceration, and scabs may recur and cause the lymph nodes behind the ear to swell. This condition is most commonly found in infants.
- Eczema around the hips | Tun Bu Shi Zheng: Papules, desquamation, and lichenification may appear around the hip with hypertropic skin. Itching may come and go. When scratched, the affected areas produced fluid.
- Scrotal Eczema | Yin Nang Shi Zheng: This condition is of two kinds: 1) dry and 2) ulcerous. Both forms are extremely tenacious in nature. They are characterized by severe itching, especially at night. In the first type, the affected areas are often covered with tiny scaling or grayish brown scabs. Hypertrophy of the skin, coarseness, and infiltrative lesions are prominent and may be accompanied by lichenification and scratching. In the second type, the affected area appears pink and dark red with ulcerated surface and fluid discharge which often stains the underwear. In some cases, ulceration may continue beneath the scab and secondary infection may also be present.
- Preumbilical Eczema | Qi Bu Shi Zheng: Mostly this condition happens to infants. This umbilicus is typically due to fluid discharge. The area around the navel usually appears red. There is ulceration, small papules, and itching. If it is complicated with infection, the affected areas is productive of purulent pus.
- Infantile Eczema | Ying Er She Zheng: This condition may appear in babies as young as one month old or in one or two year old infants. The superficial lesions manifest as tiny papules, vesicles, the discharge of pus, and scabs. They tend to appear symmetrically on the cheeks or spread to the area beneath the chin and neck. In severe cases, the shoulders, arms, lower limbs, and hip areas may also be affected. However, even if the lesions spread extensively, the center of the face, eg. the area around the mouth and nose, is not involved. This condition tends to attack babies fed with nutritious food, who look chubby but not sturdy and in whom legs appear disproportionately thin as compared to their chubby cheeks.
8. Eczema of the Hand | Shou Bu Shi Zheng: Hand eczema is likely to develop between the fingers and the palm. This condition is not only characterized by yellowish and whitish pustules which discharge yellowish pus if perforated, but also by unpredictable bouts of itching.