Discoid lupus erythematosus is a chronic inflammatory autoimmune skin disease that develops against the background of photosensitization (hypersensitivity to light). Clinical manifestations include erythema, scarring of the skin, follicular hyperkeratosis, hair loss, nail damage. The diagnosis is made on the basis of symptoms, anamnestic data, the presence of lupus cells in the blood, immunological tests and histological examination of a skin biopsy. Synthetic antimalarial drugs, topical glucocorticoids, systemic retinoids, sunscreens are used as treatment.
ICD 10
L93.0 Discoid lupus erythematosus
Meaning
Discoid lupus erythematosus (DLE), or scarring erythematosis, is a disease related to diffuse connective tissue diseases (collagenoses). This pathology is the most common form of cutaneous lupus erythematosus. The average prevalence of scarring erythematosis is 1:100,000 people. Representatives of the Caucasian race suffer more often. The onset of the disease occurs at a young age (from 20 to 40 years). Female persons are more susceptible to the incidence of discoid lupus (the ratio with men is 3:1). In rare cases (1-5%), DLE can go into systemic lupus erythematosus (SLE).
Causes
Erythematosis proceeds according to the type of autoimmune reaction, the exact cause of which is unknown. Hereditary predisposition is important in the development of the disease, as evidenced by the high incidence of discoid lupus among close relatives. In the course of research, the association of DLE with tissue compatibility antigens HLA A1, A3, A10, A11, A18, B7, B8 was established. Ultraviolet radiation has the most serious provoking effect.
Factors contributing to the occurrence of discoid lupus include permanent skin injury, chronic infections in the body, the presence of allergic diseases, taking medications that increase the sensitivity of the skin to ultraviolet light (sulfonamides, tetracycline, fluoroquinolones, griseofulvin, neuroleptics). At increased risk are people whose occupation is associated with a long stay in the open air (agricultural workers, builders, fishermen). Also at risk are persons with 1 phototype of skin (Celtic) – these are people with delicate, thin, sometimes freckled skin, having light or red hair color.
Pathogenesis
With discoid lupus erythematosus, there is a pathogenetic similarity with SLE, but pathological reactions are limited to the skin. The disease is based on autoimmune inflammation. Under the influence of ultraviolet rays, together with other provoking factors, the processes of DNA methylation (the mechanism of gene transcription regulation) are disrupted in skin cells. This leads to an increase in the expression of proteins that induce apoptosis (programmed cell death) – p53, Fas and Fas ligand and gamma interferon.
T- and B-lymphocytes stimulate the synthesis of cytokines and antibodies to the components of cell nuclei (nucleic acids, nucleosomes). The resulting immune complexes settle on the vascular endothelium, causing damage to them. The production of autoantibodies in genetically predisposed individuals can also be caused by antigens of some viruses (Epstein-Barr, cytomegalovirus, parvovirus 19) having a similar molecular structure to cell membrane proteins. An additional damaging agent is the induction of free radical oxidation of lipids. The result of these processes is massive inflammation and destruction of skin cells.
Classification
Traditionally, discoid lupus erythematosus is divided into focal and disseminated (widespread) – these forms differ in the number of foci of skin lesions and their localization. Also, in the disseminated form, there is a presence of general symptoms (weakness, fever, joint pain) and a high risk of transformation into SLE. In addition to the listed forms, the following types of DLE are distinguished in rheumatology:
- Deep. Subcutaneous nodes with their subsequent calcification are characteristic.
- Papillomatous. The pathological process affects the scalp and the skin of the hands. The foci have the appearance of warts.
- Dyschromic. Depigmentation of the central area of the discoid focus and hyperpigmentation of the peripheral zone are characteristic.
- Telangiectatic. It is manifested by an enhanced vascular pattern of foci.
- Hyperkeratotic. The stratum corneum of the epidermis is pronounced thickened. The foci resemble a skin horn. The most unfavorable form. It is considered as the initial stage of cancer.
- Centrifugal erythema Bietta. It is manifested by rashes on the back of the nose and cheeks, having a “butterfly look”.
Symptoms
Discoid lupus erythematosus is characterized by a chronic course, relapses occur mainly in summer or spring, when the length of the sunny day is maximum. Most often, areas of the body exposed to prolonged solar radiation are affected. The three most typical symptoms are erythema, follicular hyperkeratosis and scar skin atrophy.
Erythematosis debuts with the appearance on the skin of pink, slightly rising spots (erythema) 1-2 cm in size. The spots are not accompanied by itching, they increase over time, gray-white scales form on their surface. An attempt to remove the scales causes pain (a symptom of Benier-Meschersky). Also, when removing the scales at the place of their attachment to the hair follicles, areas of indentation are visible (a symptom of a “lady’s heel” or a “stationery button”). As it progresses in the center of discoid foci, the skin atrophies. Follicular hyperkeratosis is formed around the center due to blockage of follicles by epidermal scales, which looks like “goose bumps”, along the periphery of the foci – erythema, areas of increased or decreased pigmentation. Often, plugs form on the skin of the external auditory canal in the ducts of the sebaceous glands, while the surface of the skin resembles a thimble in appearance.
When foci are localized on the scalp, alopecia almost always occurs, which leaves scars. With disseminated discoid lupus, foci are located on the chest, back, elbows, palms, soles, usually do not have signs of peeling and atrophy. Sometimes the nail plates are affected. Nails turn yellow, become brittle, deformed. Very rarely, the oral mucosa is involved in the pathological process. Foci are prone to erosion, which causes burning and pain during meals.
Complications
Serious complications of discoid lupus erythematosus are rare. Sometimes secondary glandular cheilitis develops (inflammation of the small salivary glands of the red border of the lips). The disseminated form of DLE in some cases turns into SLE – a severe systemic connective tissue disease affecting the joints and almost all internal organs (heart, kidneys, lungs and central nervous system). SLE is characterized by a persistent course, difficult to treat and has a high risk of death. Transformation of persistent foci of discoid lupus into squamous cell skin cancer (squamous cell carcinoma) may also occur.
Diagnostics
Patients with this pathology are supervised by rheumatologists and dermatologists. When making a diagnosis of discoid lupus, the phototype of the skin is taken into account. At the initial consultation, the patient’s profession, taking photosensitizing medications, the presence of infectious or allergic diseases, close relatives with DLE are specified. For diagnosis , the following research methods are carried out:
General laboratory tests. In clinical blood test, there is an increase in the rate of erythrocyte sedimentation, a decrease in the level of leukocytes, platelets, in infectious and allergic pathologies – a high level of neutrophils and eosinophils. With disseminated DLE, a false positive test result for syphilis is possible.
Special rheumatology tests. Approximately 40% of DLE patients have antinuclear antibodies (ANA) and antibodies to nucleoproteins (anti-Ro/SS-A, anti-La/SS-B). Lupus (LE) cells occur in 5-7% of patients. During the immune fluorescence reaction, deposits of immunoglobulins (IgG/IgM) and complement (positive lupus stripe test) are detected. The last test can be positive for other diseases, so it is not specific.
Histological examination of a skin biopsy. A skin biopsy is the most reliable method for making a diagnosis. The following signs are characteristic – atrophy of the epidermis, thickening of the stratum corneum of the epidermis at the mouths of hair follicles, destruction of collagen fibers, edema of the dermis, deposits of hyaline in it, perivascular lymphocytic infiltrate.
It is important to distinguish the disseminated form of DLE from systemic lupus erythematosus, which requires more aggressive therapy. Help in the diagnosis of SLE is provided by the determination of antibodies to double-stranded DNA and extractable nuclear angigens in the patient’s blood. Also, discoid lupus erythematosus is differentiated from other forms of cutaneous lupus (acute, subacute), rheumatological (dermatomyositis), dermatological diseases (lichen planus, psoriasis, seborrheic dermatitis, eczema, photodermatoses, eosinophilic granuloma of the face, Broca’s angiolupoid).
Treatment
In most cases, patients are treated on an outpatient basis, but in severe cases, hospitalization in the department of rheumatology or dermatology may be required. An important point is the exclusion of taking photosensitizing medications and the treatment of concomitant allergic or infectious diseases. It is recommended to wear closed clothes, apply sunscreens or ointments containing substances that delay ultraviolet rays (mexoryl, titanium dioxide, zinc oxide).
The main pathogenetic treatment includes antimalarial aminoquinoline drugs (Hydroxychloroquine), topical glucocorticosteroids (THC), vitamin A derivatives – retinoids (Isotretinoin, Acitretin). Due to the frequent development of retinopathy against the background of taking hydroxychloroquine, a regular examination by an ophthalmologist is mandatory. Depending on the localization of discoid foci, THCs of different activity are used. When foci are located only on the skin of the face, THCs of weak and moderate activity (Hydrocortisone acetate, Methylprednisolone) is used, when the skin of the extremities and trunk is affected, THCs of strong activity (Betamethasone, Triamcinolone) is recommended. If discoid foci are present on the palms and soles, ultrahigh activity TGCs (Clobetasone) are prescribed.
Antioxidants (alpha-tocopherol) are effective for suppressing free radical damage to skin cells. If standard treatment is ineffective, they resort to drugs with a pronounced immunosuppressive effect – Tacrolimus, Methotrexate, Azathioprine.
Prognosis and prevention
In the vast majority of cases, discoid lupus has a favorable course. With proper selection of therapy and compliance with all recommendations, a stable remission occurs. The main problem is the transformation of DLE into more severe diseases with a fairly high mortality rate – SLE and squamous cell carcinoma. Prevention of relapses of discoid lupus consists in limiting the time spent in the sun, wearing closed clothes, using sunscreen preparations, excluding taking medications that increase the sensitivity of the skin to ultraviolet radiation.