Endogenous factors include abnormal immune function and systemic diseases (such as endocrine diseases, nutritional disorders, chronic infections, etc.), as well as hereditary or acquired skin barrier dysfunction.
External causes mainly include allergens in the environment or food, irritants, microorganisms, changes in ambient temperature or humidity, and sun exposure, all of which can trigger or aggravate eczema.
Psychosocial factors such as stress and anxiety can also trigger or aggravate the disease.
Basic etiology
Genetic factors
Genetics is the most important factor in determining whether a person is allergic or not, and many eczema patients have varying degrees of hereditary factors, the most typical atopic eczema (hereditary atopic dermatitis or atopic dermatitis), it was found that 70% of the children of those who have atopic (hereditary atopic) constitutions will suffer from atopic eczema, and if one of them is atopic, 70% of the children will suffer from atopic eczema, and if one of them is atopic, 70% of the children of the children will suffer from atopic eczema. Studies have found that 70% of children born to atopic (genetically allergic) parents will develop atopic eczema, and 50% of children born to atopic parents will develop atopic eczema.
Immune abnormalities
Eczema patients often have Th2 cell activation, increased eosinophils in the blood, increased serum IgE levels, etc., and when allergen testing is performed, there is often lgE corresponding to a variety of allergens.
Changes in women's hormone levels
Some female patients with chronic eczema may have lesions appearing cyclically during the premenstrual period or the menstrual period. This is due to the patient's production of autoantibodies to endogenous progesterone late in the menstrual cycle, which may be associated with an allergic reaction.
Some women who are pregnant may develop an eczema-like rash with intense itching, which may be due to allergy to progesterone, and which disappears quickly after a period of postpartum.
Endocrine and metabolic diseases
Diabetes, thyroid disease can easily lead to itchy skin and eczema, sometimes often the first symptom of the disease, these patients often first itchy skin, long time the skin appeared pimples, plaques and hypertrophic plaques, such as subacute and chronic eczema manifestations, the general effect of anti-allergy treatment is poor. In addition to itching and eczema, there may be other skin manifestations such as cutaneous mucous edema (in patients with hyperthyroidism), vascular lesions and fungal infections (in patients with diabetes mellitus).
Chronic infectious foci
Some patients with chronic eczema tend to have chronic infectious foci, such as chronic gastritis, chronic cholecystitis, chronic appendicitis, chronic genitourinary infections, and infected foci in the throat or paranasal sinuses. Eczema in these patients tends to come and go, and once these foci of infection are cleared, eczema tends to heal.
Triggering factors
Dietary habits and inhalants
Many patients have eczema related to poor dietary habits:
Some patients are allergic to alcohol but do not abstain from alcohol;
Some patients suffer from long-term alcohol abuse, leading to gastrointestinal and liver diseases, secondary to eczema;
Some patients have a long-term irregular life, so that the body's normal biological The normal biological rhythm of the body is disrupted, leading to eczema and other diseases;
Some patients are partial to spicy food, leading to eczema or make eczema aggravated.
Certain foods have strong antigenic properties, or due to the increased permeability of the digestive tract, or due to the decreased function of the liver to process and detoxify foreign proteins, which can easily cause a perverse reaction, thus causing eczema. These foods include animal and plant-based:
Beef, lamb, chicken;
Sea fish (cod, lobster, scallops, scallops, etc.), shellfish, freshwater fish (salmon, perch, carp, etc.), shrimp, crab, snails, etc.
Peaches, cucumbers, cantaloupe, strawberries, apples, lemons, mangos, plums, apricots and so on;
Taro, hairy shoots, wheat, cilantro, peanuts, garlic cloves, spinach, eggplant, tomatoes, etc.
Some inhalants are most likely to cause allergic rhinitis and asthma, and occasionally eczema:
Animal dander, such as dog hair, cat hair, etc.
Fungi, such as Penicillium idiosyncraticum, polydominant dendritic spores, Aspergillus fumigatus, Aspergillus hinged spore molds, Penicillium nodosum, and Rhizopus niger molds, etc.
Mites, such as house dust mites, dust mites, etc.
Pollen, which is commonly found in willow trees, poplar, elm, mulberry, sycamore, etc.;
Dwarf ragweed, artemisia, house dust, alcohol, humulus, etc.
Chemicals
Other substances that may aggravate eczema are food additives, natural or synthetic substances in food, including artificial colors, preservatives and antioxidants, yeast, salicylic acid, citric acid, benzoic acid derivatives, alcohol, etc., which may be present in medicines, chewing gum and even toothpaste.
Local factors
Eczema-like lesions can occur at the site of wounds and skin infections, which may be related to local microorganisms, necrotic tissues, or medications, etc. *** with the action, manifested as redness of the skin around the wounds or infected foci, dense small papules, and obvious itching. These patients are prone to self-sensitizing dermatitis, i.e., an eczema-like rash can also occur at a distance, especially papules and small blisters on the hands and feet.
In addition, female genital eczema often due to menstruation and leukorrhea stimulation and prolonged, some folds of eczema is often associated with excessive secretion of sweat and not easy to evaporate.
Spiritual factors
Many patients with chronic eczema have long-term insomnia, anxiety, dreamy, sweaty and other autonomic disorders, some patients are in the spirit of a huge trauma after the occurrence of eczema, some patients with skin behavioral disorders, and repeated use of a variety of soaps, baths, and even irritating stronger detergent to clean the body, which over time leads to eczema.
These patients' mental trauma and eczema often form a vicious circle, seriously affecting patients' physical and mental health. After the mental factors are effectively treated, eczema can gradually improve and heal.