Eczema is an inflammatory skin disease caused by a variety of internal and external factors with a pronounced tendency to exude, accompanied by significant itching, prone to recurrence, and seriously affecting the quality of life of patients. It is a common disease in dermatology, with a prevalence of about 7.5% in our general population and 10.7% in the United States.
I. Etiology and pathogenesis
The etiology of eczema is still unclear. Endogenous factors include abnormal immune function (such as immune imbalance, immunodeficiency, etc.) and systemic diseases (such as endocrine diseases, nutritional disorders, chronic infections, tumors, etc.) and hereditary or acquired skin barrier dysfunction, external factors such as environmental or food allergens, irritants, microorganisms, environmental temperature or humidity changes, sun exposure, etc. can trigger or aggravate eczema. Psychosocial factors such as stress and anxiety can also trigger or aggravate the disease.
The pathogenesis of this disease is not clear. Currently, it is believed that the disease is the result of a combination of internal and external factors based on internal factors such as abnormal immune function and skin barrier dysfunction. Both immune mechanisms such as allergic reactions and non-immune mechanisms such as skin irritation are involved in the pathogenesis. Microorganisms can trigger or aggravate eczema through direct invasion, superantigen action or induction of immune response.
Second, the clinical manifestations
The clinical manifestations of eczema can be divided into three phases: acute, subacute and chronic. The acute phase is characterized by erythema, edema on the basis of corn-grain papules, papules, blisters, vesicles and exudate, the center of the lesion is often heavy, and gradually spread to the periphery, and scattered papules, papules, so the boundary is unclear. In the subacute stage, redness and exudation are reduced, and the vesicular surface is crusted and desquamated. Chronic eczema mainly manifests as rough hypertrophy, moss-like changes, may be accompanied by pigment changes, hand and foot eczema can be accompanied by nail changes. The rash is generally symmetrically distributed, often recurrent, and the conscious symptoms are pruritus and even severe itching.
Laboratory tests
Blood tests may include eosinophilia, increased serum eosinophilic cationic protein, increased serum IgE in some patients, allergen tests to help find possible allergens, patch tests to help diagnose contact dermatitis, fungal tests to identify superficial fungal disease, scabies tests to help rule out scabies, serum immunoglobulin tests to help identify The congenital disease with eczema dermatitis lesions, bacterial culture of skin lesions can help diagnose secondary bacterial infections, etc., and skin histopathological examination should be performed when necessary.
IV. Diagnosis and differential diagnosis
The diagnosis of eczema is mainly based on clinical manifestations, combined with the necessary laboratory tests or histopathological examinations. Special types of eczema are diagnosed according to clinical characteristics, such as lack of lipid eczema, self-sensitivity dermatitis, coin-shaped eczema, etc.; non-specific can be diagnosed according to clinical sites, such as hand eczema, calf eczema, perianal eczema, breast eczema, scrotal eczema, ear eczema, eyelid eczema, etc.; generalized eczema refers to eczema that occurs simultaneously in multiple sites. The severity of eczema can be scored according to its size and the characteristics of the rash.
It needs to be differentiated from the following diseases.
(1) other diseases similar to eczema, such as scabies, superficial fungal disease, lymphoma, eosinophilia, pellagra, etc. ;
(2) congenital diseases with eczema lesions, such as Wiskott-Aldrich syndrome, selective IgA deficiency, high IgE recurrent infection syndrome, etc;
(3) other types of dermatitis with specific etiology or clinical manifestations, such as atopic dermatitis, contact dermatitis, seborrheic dermatitis, bruising dermatitis, polymorphic heliotrope, etc.
V. Treatment
The main goal is to control symptoms, reduce recurrence, and improve the quality of life of patients. Treatment should be considered as a whole, taking into account both the immediate and long-term efficacy, with special attention to medical safety in treatment.
(1) Basic treatment
①Patient education: the nature of the disease, possible regression, the impact of the disease on physical health, the presence of infectiousness, the clinical efficacy of various treatment methods and possible adverse effects need to be explained. Instruct patients to look for and avoid common allergens and irritants in the environment, and to avoid scratching and excessive washing. Corresponding advice should also be given on the environment, diet, use of protective equipment, and skin cleansing methods.
② Avoid triggering or aggravating factors: Through detailed history taking, meticulous physical examination, and reasonable use of diagnostic tests, carefully search for various suspected causes and triggering or aggravating factors in order to achieve the goal of removing the causes and thorough treatment. For example, the factors that make the skin dry should be removed for lack of lipid eczema, and the primary infection should be treated for infectious eczema.
③Protect the skin barrier function: eczema patients have damage to the skin barrier function, easy to secondary irritant dermatitis, infection and allergy and aggravate the lesions, so it is very important to protect the barrier function. Treatment that does not irritate the patient’s skin should be chosen, secondary infections should be prevented and dealt with in a timely manner, and moisturizers should be added for subacute and chronic eczema with dry skin.
(2) Topical treatment: is the main means of eczema treatment. Suitable drug formulations should be selected according to the stage of the lesion. In the acute stage without blisters, vesicles, exudation, it is recommended to use furnace glycolate lotion, glucocorticoid cream or gel; a large amount of exudation should choose cold wet compresses, such as 3% boric acid solution, 0.1% berberine hydrochloride solution, 0.1% Levanox solution, etc.; vesicles but not much exudation when available zinc oxide oil. For subacute lesions, topical zinc oxide paste and glucocorticoid cream are recommended. For chronic lesions, topical glucocorticoid ointment, hard cream, emulsion or tincture is recommended, and moisturizers and keratolytic agents such as 20%-40% urea ointment and 5%-10% salicylic acid ointment can be used in combination.
Topical glucocorticoid preparations are still the mainstay of eczema treatment. The initial treatment should be based on the nature of the lesions and the appropriate strength of glucocorticoids: weak glucocorticoids such as hydrocortisone and dexamethasone cream are recommended for mild eczema; strong hormones such as harcionade and halometasone cream are recommended for severe hypertrophic lesions; medium hormones such as tretinoin and mometasone furoate are recommended for moderate eczema.
Those suspected to be related to bacterial infection may combine topical antibiotic preparations or use compound preparations containing antibacterial effects. Weak or medium-acting hormones are generally effective in pediatric patients, lesions on the face and skin folds. Strong glucocorticosteroids should not be used continuously for more than 2 weeks to reduce acute tolerance and adverse effects.
Calcium-regulated neurophosphatase inhibitors such as tacrolimus ointment and pimecrolimus cream have a clear therapeutic effect on eczema without the side effects of glucocorticoids and are particularly suitable for the treatment of eczema on the head, face and inter-rub areas.
Bacterial colonization and infection can often induce or aggravate eczema8, so antibacterial drugs are also an important aspect of topical treatment. Various topical preparations of antimicrobials and chemical antibacterial drugs are available, as well as a combination of glucocorticoids and antibacterial drugs.
Other topical drugs such as tar, antipruritic agents, and topical preparations of nonsteroidal anti-inflammatory drugs can be selected for application according to the situation.
(3) Systemic treatment.
①Antihistamines: appropriate antihistamines are selected to stop itching and anti-inflammation according to the patient’s condition.
②Antibiotics: For those with extensive infection, systemic application of antibiotics for 7-10 days is recommended.
③Vitamin C, calcium gluconate, etc. have certain anti-allergic effect and can be used for acute attacks or obvious itching;
④Glucocorticoids: Routine use is generally not advocated. They are suitable for patients with clear etiology and short-term elimination of etiology, such as those caused by contact factors, drug factors or self-sensitivity dermatitis; for severe edema, generalized rash, erythroderma, etc., they can also be applied short-term for rapid symptom control, but caution must be exercised to avoid systemic adverse reactions and rebound of the disease.
⑤ Immunosuppressants: should be used with caution, to strictly grasp the indications. They should only be used in patients with severe disease who have contraindications to the application of glucocorticosteroids, or when the condition is significantly relieved by short-term systemic application of glucocorticosteroids, and when the use of hormones needs to be reduced or stopped.
(4) Physical therapy: UV therapy includes UVA1 (340-400 nm) irradiation, UVA/UVB irradiation and narrow-spectrum UVB (310-315 nm) irradiation, which is more effective for chronic intractable eczema.
(5) Chinese herbal therapy: Chinese herbal medicine can be treated internally as well as externally, and should be administered according to the evidence of the condition. Chinese herbal extracts such as compound glycyrrhizin and tretinoin polysaccharide are effective for some patients. It should be noted that herbal medicines can also lead to serious adverse reactions, such as allergic reactions, liver and kidney damage, etc.
(6) Follow up and prevention: The disease is prone to recurrence and patients are advised to follow up regularly. Patients with acute eczema should preferably be seen once 1 week after treatment, 1-2 weeks after treatment for subacute patients, and 2-4 weeks after treatment for chronic patients. The follow-up visit is to evaluate the efficacy, changes in condition, the need for further tests, and to evaluate compliance. In cases of recurrent attacks that persist without healing, attention is paid to analyzing the presence of.
① irritating factors;
②Negligent exposure to allergens;
(iii) cross-allergy;
④Secondary allergy: e.g. allergy to topical medication in treatment;
⑤ secondary infection;
⑥Adverse environmental factors and adverse systemic factors, etc.