Eczema is a common form of epidermal inflammation. Its etiology is complex and may be related to certain internal and external factors, although external causes are not evident in most patients. It is generally believed to be closely associated with allergic reactions. The main characteristics of eczema include severe itching, skin lesions of various forms—primarily small papules—a tendency toward exudation, recurrent episodes, and a propensity to become chronic.
I. Etiology
The causes of this disease are complex. There are numerous sensitizing factors, which are often difficult to identify. Some patients are allergic to multiple factors.
Food-related: Allergies to fish, shrimp, beef, and lamb. A small number of individuals are allergic to fats and sugars;
Inhalants: Pollen, dust mites, wool, and feathers;
Focal infections: such as tonsillitis, gingivitis, biliary tract inflammation, and intestinal parasites;
Endocrine and metabolic disorders: such as pregnancy, menstrual disorders, and diabetes;
Physical factors: Common physical factors such as cold, moisture, heat, and scratching can all trigger eczema;
Bacterial infections: Bacterial infections on the skin surface are also common triggers for eczema;
Neuropsychological factors: Factors such as excessive fatigue, mental stress, insomnia, anxiety, severe emotional fluctuations, and autonomic nervous system dysfunction can exacerbate eczema or trigger relapses; intense sunlight and irritating foods such as tobacco, alcohol, and chili peppers can also easily worsen the condition or cause relapses;
Predisposition to eczema: Some researchers believe that a predisposition to eczema is necessary for its development. This predisposition may be related to genetic factors, physiological changes caused by certain systemic diseases, or immune regulation.
During the course of the disease, a patient’s sensitivity to various stimuli may continuously increase or gradually decrease. In the acute phase, even factors that do not typically trigger the condition can exacerbate the symptoms. However, if the patient receives timely and appropriate treatment, this sensitivity may gradually decrease. Many factors that previously triggered the condition may no longer be pathogenic, leading to gradual improvement or even complete recovery.
II. Clinical Manifestations of Eczema
The clinical symptoms of this condition can be divided into three stages based on the rate of onset: the acute stage, the subacute stage, and the chronic stage.
Acute Eczema: Skin lesions are polymorphic. Initially, numerous dense, punctate erythematous macules, millet-sized papules, and papulovesicles appear on the skin. The base of the papules is erythematous and slightly swollen. As the condition progresses, the papules and papulovesicles can rapidly develop into small vesicles; once these vesicles rupture, they form erosions. The lesions tend to coalesce into patches and spread peripherally.
(1) This condition can occur on any part of the body, but it is more common on exposed areas such as the head, face, distal extremities, and hands and feet, often presenting with a symmetrical distribution. Eczema also frequently occurs in skin folds, such as the axillae, groin, perineum, and perianal region.
(2) Patients report symptoms such as itching and a burning sensation. The severity of itching depends on the location of the lesions, the severity of the condition, and the patient’s tolerance. Eczema in the genital and perianal areas tends to be more intensely itchy than eczema in other areas. Patients with low tolerance may experience sleep disturbances or insomnia due to the itching; the more they lose sleep, the worse the itching becomes; the more they scratch, the worse the itching gets—creating a vicious cycle.
(3) Examination: In addition to papules, papulovesicles, or scratch marks on the skin, acute eczema may present with noticeable swelling in areas of loose skin, such as the scrotum and face. In cases of infection, the exudate may be purulent, accompanied by swollen lymph nodes in the affected area.
(4) If acute eczema is treated promptly and appropriately, it can gradually improve and eventually resolve; otherwise, it is prone to progressing to subacute or chronic eczema.
Subacute Eczema: After the acute inflammatory symptoms of acute eczema—such as redness, swelling, and exudation—have subsided, the affected areas may still exhibit small papules along with a few papulovesicles, small vesicles, mild erosion, crusting, and scaling. Itching remains relatively severe. With treatment over several weeks, the condition may gradually improve or resolve completely; however, in some cases, it may progress to a chronic course. If new irritating factors arise during this stage, acute lesions may reappear.
Chronic Eczema: When eczema persists without resolution, the skin lesions exhibit chronic inflammation. The affected skin becomes thickened, with a rough, lichenified surface, accompanied by hyperpigmentation, punctate exudation, scratch marks, blood crusts, and scaling. The skin lesions are mostly localized, and the itching remains intense or occurs in episodes. Itching is particularly severe when exposed to heat or during sleep.
(1) Sites of chronic eczema: It is commonly found on the hands, feet, lower legs, antecubital fossae, thighs, vulva, and anal region. It often presents symmetrically and has a prolonged course, lasting for months or even years.
(2) Characteristics of eczema in different areas
① Eczema of the hands: Prone to climatic influences, with milder symptoms in winter; it is easily exacerbated by soap or detergents.
② Eczema of the auricle and external auditory canal: Itching is severe and may worsen due to scratching or be accompanied by a fungal infection.
③ Eczema of the breasts: Seen in lactating women, it presents with papulovesicular lesions, erosion, exudation, and fissures on the nipples and areolae, accompanied by itching and pain; it often occurs symmetrically. It usually resolves after breastfeeding is discontinued.
④ Eczema of the vulva and scrotum: Due to severe itching, excessive scratching can lead to acute swelling or erosion, making walking difficult. If there are prolonged, recurrent episodes accompanied by chronic infection, the local skin may develop rubber-like changes.
⑤ Lower Leg Eczema: Also known as stasis dermatitis, this condition is more common in men. Rashes typically occur on the lower third of the lower leg and are often triggered by prolonged standing, excessive weight-bearing, or lower limb edema, which can impair venous circulation in the lower extremities. The affected skin appears dark red and may exhibit scattered punctate papules, erosions, skin thickening, and ulcers. Eczema of the lower legs is often accompanied by hyperpigmentation.
(3) Characteristics of Eczema of Different Shapes
① Numular Eczema: Commonly occurs on the backs of the hands and feet, fingers, and limbs. Recurrences often occur in the same area. Lesions appear as round, coin-shaped plaques, 1–3 centimeters in diameter, with well-defined borders. They consist of small red papules or papulovesicles that have fused together and may exhibit mild exudation, crusting, and scaling. This type of eczema has a relatively long course, is prone to recurrence, and is most common in winter, often associated with dry weather. Patients typically experience varying degrees of itching.
② Dry Eczema: Also known as non-seborrheic eczema, this type can occur anywhere on the body but is most common on the limbs, particularly in elderly individuals with dry skin or those who bathe excessively with soap. It results from reduced sebum secretion, dry climatic conditions, and loss of skin moisture. The patient’s epidermis and stratum corneum exhibit fine fissures and bran-like scaling, and the skin appears pale red.
III. Diagnosis of Eczema
The diagnosis of eczema is based on polymorphic skin lesions and symmetrical distribution. The affected skin initially presents with diffuse erythema, followed by clusters of papules and vesicles, intense itching, erosion, exudation, and crusting. Finally, desquamation and hyperpigmentation occur. As the condition often recurs, diagnosis is generally straightforward.
Acute eczema must be distinguished from contact dermatitis. In the latter, patients have a history of exposure to sensitizing substances; lesions are confined to the areas exposed to the sensitizing chemicals; rashes are typically of a single type with well-defined borders; large blisters may be present; and patients may experience a burning sensation at the affected sites. The course of the disease is short, and it is relatively easy to cure once the cause is removed.
Chronic eczema must be distinguished from neurodermatitis. In neurodermatitis, itching precedes the rash; skin lesions exhibit lichenification and rarely exude. It most commonly occurs on the neck, the extensor surfaces of the limbs, and the sacrococcygeal region.
Eczema of the hands and feet is often confused with tinea manuum and tinea pedis. Tinea manuum and tinea pedis most commonly occur on the palms and soles, may present with small blisters or dry scaling, and often affect only one side; in contrast, hand and foot eczema typically affects the dorsal surfaces of both hands and feet, is prone to exudation, and tests negative for fungi.
IV. Treatment of Eczema
Modern Medical Treatment
(1) Systemic Treatment: Use of antihistamines and sedatives. For acute and subacute eczema, intravenous injections of calcium or sodium thiosulfate may be administered. For refractory cases, corticosteroids may be used for a short period; once the condition improves, the dosage should be gradually tapered off. Caution is advised when treating elderly patients with eczema, and corticosteroids should be avoided in patients with certain systemic diseases such as diabetes, peptic ulcers, tuberculosis, and bleeding disorders.
(2) Topical Treatment
① Acute Eczema: When there is no exudation, calamine lotion may be applied, or a 3% boric acid solution may be used as a cold compress. If erosion and exudation are present, corticosteroid-containing ointments or creams may be applied topically to small areas.
② Subacute Eczema: When there is minimal exudation, apply wet compresses using the solutions mentioned above. Once the area has dried and formed a scab, apply lotions or ointments topically; antibiotic-containing lotions or ointments may also be used to control infection.
③ Chronic Eczema: Tar-based medications are recommended, such as 5% coal distillate or coal tar ointments applied topically.
Traditional Chinese Medicine Treatment: Traditional Chinese Medicine views eczema as a common allergic and inflammatory skin condition. It is characterized by recurrent, symmetrical lesions and intense itching. Depending on the affected area, it is known by different names: when it occurs on the ears, it is called “Xuan’erchuang”; on an infant’s face, “Naixuan”; on the lower legs, “Shiquanchuang”; on the scrotum, “Shencangfeng” or “Xiqiufeng”; eczema occurring on the elbows and knees is called “four-bend wind.”
This condition generally has a prolonged course with recurrent flare-ups. Its etiology is complex and is related to factors such as constitutional predisposition, nervous system status, endocrine function, blood circulation, digestion, metabolism, nutrition, organ function, as well as bacteria, fungi, parasites, focal infections, and allergies. Stress from work and study, changes in lifestyle, and emotional fluctuations that affect endocrine function are important factors contributing to the onset of this disease.
Patients typically present with diffuse local redness initially, followed by clusters of papules and vesicles, intense itching, erosion, exudation, and crusting. The condition eventually resolves with desquamation and hyperpigmentation. However, it is prone to recurrence, and consumption of seafood or irritating foods can exacerbate symptoms or trigger a relapse.
For the treatment of eczema, it is essential to see a doctor promptly and follow the physician’s recommendations. Do not self-medicate by purchasing and applying over-the-counter anti-itch creams, as some skin conditions present with very similar symptoms but require different treatments; improper medication may worsen the condition. Since this condition is easier to cure during acute flare-ups but more difficult to treat in its chronic form, it should be treated as early as possible during an acute episode.
For acute eczema, when there is severe damp-heat accompanied by redness, swelling, and exudation, the treatment principle should be to clear heat, purge fire, cool the blood, and drain dampness; Longdan Xiegan Decoction with appropriate modifications may be used. For subacute eczema, the treatment principle is to strengthen the spleen and drain dampness; Chushui Gailing Decoction with appropriate modifications may be used. Chronic eczema is often stubborn and difficult to cure. Based on pattern differentiation, the treatment principle should be to nourish the blood, dispel wind, invigorate blood circulation, and moisten dryness; the Siwu Xiaofeng Decoction, with appropriate modifications, may be used.
For chronic eczema, a wet compress made by decocting equal parts of Sophora flavescens, Cnidium monnieri, and Xanthium sibiricum in water may be applied. For acute eczema, a wet compress made by decocting Scutellaria baicalensis and Glycyrrhiza uralensis in water may also be used.
Acupuncture Therapy: Select acupoints such as Quchi (LI11), Zusanli (ST36), Weizhong (BL40), and Xuehai (SP10) for needling. For auricular acupuncture, select points such as the Lung point, Shenmen, Subcortical, and Endocrine points. Moxibustion using moxa rolls may also be used for treatment. During treatment, avoid foods that irritate the skin (such as chili peppers and garlic); do not drink alcohol; avoid seafood and beef; do not use hot water when bathing; and do not use soap.