Discoid erythema

Introduction Discoid lupus erythematosus (DLE) is a chronic recurrent disease that primarily invades the skin and is characterized by well-defined red patches (erythema), hair follicle embolism, scales, telangiectasia, and skin atrophy. The cause is unclear. More common in women, the highest incidence rate around 30 years old. The disease can be divided into two types: 1 limited skin damage is limited to the skin above the neck, 2 disseminated skin lesions affect the skin of a wide range of parts of the body. Some authors believe that the disseminated type is easily converted to systemic lupus erythematosus.

Cause

(1) Genetic background: The prevalence of this disease varies among different races. Different strains of mice (NEB/NEWF, MRL1/1pr) spontaneously develop SLE symptoms after several months of birth. Family surveys show that SLE patients have First, about 10% to 20% of the second-degree relatives may have the same kind of disease, some have hyperglobulinemia, a variety of autoantibodies and T inhibit cell dysfunction.

(B) drugs: There are reports in 1193 cases of SLE, the incidence of drugs and drug-related people accounted for 3% to 12%. Drug-induced diseases can be divided into two categories, the first is drugs that induce SLE symptoms such as penicillin, sulfonamides, phenylpredyl, gold preparations. These drugs enter the body, first cause allergic reactions, and then stimulate the quality of lupus or potential SLE patients with idiopathic SLE, or exacerbate the condition of already suffering SLE, usually stopping the drug can not prevent the disease from developing. The second category is drugs that cause lupus-like syndrome, such as hydrazine hydrochloride (hydralazine), procainamide, chlorpromazine, phenytoin sodium, isoniazid, etc. After prolonged and large doses, patients may experience clinical signs and laboratory changes in SLE. High, recognized as the genetic quality of drug-induced SLE. The difference between drug-induced lupus-like syndrome and idiopathic lupus erythematosus is: 1 clinical Qinghai, involving less kidney, skin and nervous system; 2 older age; 3 shorter and lighter course; 4 no reduction in blood complement ; 5 serum single-stranded DNA antibody positive.

(3) Infection: Some people think that the onset of SLE is related to certain viruses (especially lentivirus) infection. Substances resembling inclusion bodies can be found in patients with glomerular endothelial cytoplasm, vascular endothelial cells, and lesions. At the same time, the patient's serum increased the virus titer, especially for measles virus, parainfluenza virus type III, Epstein-Barr virus, rubella virus and viscovirus. In addition, there are dsRNA, ds-DNA and RNA-DNA antibodies in the patient's serum. It can only be found in tissues with viral infection. Under the electron microscope, these inclusion bodies are in the form of small tube network, 20~25m in diameter, clustered, but in dermatomyositis, scleroderma, acute sclerosis. It can also be seen in the middle.

an examination

Related inspection

Serum complement C3 blood routine immunoelectrophoresis Coombs test

Most of the patients are women, aged 20 to 40 years old. Skin lesions occur on the face, especially on the cheeks and bridge of the nose. Secondly, it occurs in the lips, ears, scalp, back of the hands and fingers. The characteristics of the skin lesions are persistent discoid erythema with clear edges, slightly raised, dark pigmentation, and the size of the soybeans to the nails. Shape or not regular, the surface of the capillaries dilate, and covered with adhesive scales, if the scales are stripped, the dilated follicular pores can be seen, and the scaly bottom has many thorny horny ridges, which are tied in the hair follicle mouth.

Differential diagnosis

The disease needs to be identified with the following diseases:

1. Chronic pleomorphic sun rash: Patchy pleomorphic sun rash is similar to this disease. In the early stage, it is difficult to distinguish between clinical and pathological. However, irradiation with a certain dose of ultraviolet light can induce skin rash on the normal skin of patients with patchy pleomorphic sun rash, and the skin of lupus patients can not induce skin lesions, thereby identifying the two. In addition, the skin lesions of chronic polymorphic sun rash are exposed to sunlight, and the skin lesions have no sticky scales and atrophy.

2. Seborrheic dermatitis and psoriasis Seborrheic dermatitis or early psoriasis: may be butterfly-shaped, distributed on the face of the bridge of the nose, can be confused with discoid lupus erythematosus, but the histological changes of lesion biopsy obviously different. In addition, seborrheic dermatitis generally responds well to topical treatment, and this disease does not respond well to topical treatment.

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