What is lupus maculae

Systemic lupus erythematosus is an autoimmune disease. The cause of this disease has not been fully confirmed yet, but it is generally related to genetic factors and sex hormones. Patients with lupus erythematosus will have obvious symptoms, such as red and swollen patches of varying sizes on the skin, and damage to internal organs, so friends must pay more attention.

Causes

The cause of the disease is not yet fully understood, but it is currently believed to be related to the following factors.

1. Genetic factors

The onset of systemic lupus erythematosus tends to cluster in families, with 0.4% to 0.5% of first- or second-degree relatives of SLE patients suffering from LE or other autoimmune diseases; the rate of SLE in monozygotic twins can be as high as 70% (24% to 69%), while in fraternal twins the rate is 2% to 9%; more than 50 gene loci related to SLE have been found, most of which are HLA II and III genes, such as DR2, DR3, DQA1, DQB1 in the D region of HLA II and C4AQ in the HLA III gene.

2. Sex hormones

This disease is more common in women of childbearing age, and pregnancy can induce or aggravate SLE. But the evidence is insufficient.

3. Environmental factors and others

Ultraviolet radiation can stimulate or aggravate LE, which may be related to its damage to keratinocytes, DNA changes or the release of "hidden antigens" or the expression of new antigens, which causes the body to produce corresponding antibodies, thereby forming immune complexes and causing damage. Drugs such as hydralazine, procaine, methyldopa, isoniazid, penicillin, etc. can induce drug-induced lupus erythematosus. Certain infections (such as streptococci, Epstein-Barr virus, etc.) can also induce or aggravate the disease.

Clinical manifestations

Discoid lupus erythematosus: Mainly affects the skin and is the lightest type of lupus erythematosus. A few may have mild visceral damage, and a few cases may develop into systemic lupus erythematosus. Skin lesions initially appear as one or several bright red spots, the size of mung beans to soybeans, with sticky scales on the surface. They gradually expand and become round or irregular in shape, with the edges significantly darker in pigment and slightly higher than the center. The center is pale, may shrink and become low-lying, and the entire lesion is disc-shaped (hence the name discoid lupus erythematosus). The lesions are mainly distributed in sun-exposed areas such as the face, earlobes and scalp. A few cases may involve the upper chest, back of the hands, forearms, lips and oral mucosa. Most patients have no symptoms of skin lesions, but it is difficult for them to disappear completely. New lesions may gradually increase or remain unchanged for many years. The lesions are sparsely and symmetrically distributed, or they may merge into pieces. Lesions in the middle of the face may merge into a butterfly shape. Discoid lesions worsen after sun exposure or exertion. Damage to the scalp can cause permanent hair loss. Old lesions occasionally develop into squamous cell carcinoma of the skin.

Subacute cutaneous lupus erythematosus is less common clinically and is a special intermediate type. There are two types of skin lesions. One is the annular erythema type, which is single or multiple scattered erythema, in the shape of annular, semi-annular or multi-annular, with a dark red edge that is slightly edematous and raised, a red halo on the outer edge, and pigmentation and capillary dilation left after the center fades. It is common on the face and trunk. The other type is the papulosquamous type, in which the skin lesions appear similar to psoriasis, with erythema, papules and plaques. There are obvious scales on the surface, mainly distributed on the trunk, upper limbs and face. In most cases, the two types of skin lesions exist alone, but in a few cases they may exist at the same time. Skin lesions often recur, and the vast majority of patients have visceral damage, but severe cases are rare. The main symptoms are joint pain, muscle pain, and recurrent low-grade fever. A few have nephritis and blood system changes.

Systemic lupus erythematosus is the most serious type of lupus. The vast majority of patients show multi-system damage at the onset of the disease, and a small number of patients develop the disease from other types of lupus erythematosus. Some patients also have other connective tissue diseases, such as scleroderma, dermatomyositis, Sjögren's syndrome, etc., forming various overlapping syndromes. The clinical manifestations of systemic lupus erythematosus are diverse, complex, and often severe, and may endanger the patient's life due to lupus nephritis, lupus encephalopathy, and side effects of long-term and excessive use of drugs.