Lichen planus

Introduction to lichen planus Lichenplanus is also known as lichenruberplanus. It is a characteristic purple-red flat papule, maculopapular rash, and a chronic skin disease. An inflammatory skin disease that can affect the skin, mucous membranes, nails, and hair. It occurs in the chronic inflammation of the superficial dermis and also invades the oral mucosa. basic knowledge Sickness ratio: 0.05% Susceptible people: no specific people Mode of infection: non-infectious Complications: erythroderma

The cause of lichen planus

(1) Causes of the disease

So far, there is no conclusion, there are autoimmune, infection, neuropsychiatric factors, the role of cytokines, family genetics and other doctrines, drug factors, endocrine abnormalities, chronic lesions and other factors can also induce the disease, it has been found in patients with lichen planus The structure of -6-phosphate dehydrogenase (G-6-PD) may be abnormal. Some people have the opposite opinion. In addition, the activity of respiratory enzymes and coenzymes in the rash has changed. Whether these abnormalities are the cause of lichen planus has not been determined.

(two) pathogenesis

In recent years, he has conducted more research on its pathogenesis and proposed a variety of theories.

1. Autoimmune lichen planus is associated with certain autoimmune diseases, and helper cells such as Langerhans cells and keratinocytes participate in these reactions, activate T cells, proliferate, and move to the epidermis, which produces certain cytokines. Lymphatic toxins and cytotoxic T cells cause destruction and damage of basal cells, which cause a series of pathological changes of lichen planus. Experiments have shown that CD3 is present in lichen planus, CD8 cells are elevated, CD4/CD8 is decreased, and generalized CD4 /CD8 was significantly reduced. Some scholars used indirect immunofluorescence technique to detect the specific antigen of lichen planus (LPSA) in the epidermis of the lesions of patients with oral lichen planus. Specific antibodies against LPSA were detected in the blood. Moss patients have lichen planus-specific antinuclear antibodies, and the detection rate varies depending on the substrate used. The optimal substrate is rat esophageal epithelium, which has a high detection rate of mucosal erosion.

In terms of humoral immunity, IgM values were found to be low during the active period of lichen planus or when the skin lesions just subsided, while normal cases were normal in cases of old lesions.

2. In recent years, it has been reported that the prevalence of hepatitis C virus (HCV) DNA in patients with lichen planus has increased, suggesting that HCV plays an important role in the pathogenesis of lichen planus, whether HCV is present in lesions and its replication remains. Further research is needed.

3. In some cases, the skin lesions will improve or disappear after the mental symptoms are improved or disappeared. However, some authors have found that there is no significant difference in neuropsychiatric conditions between patients and healthy people through controlled studies.

4. Many studies have shown that cytokines secreted by keratinocytes, active T cells, etc. may play an important role in the formation of lichen planus, such as thymocyte activity factor (ETAF), T cell growth factor (KTGF), lymphatics. Cellular chemokines (LCF) and IL-1, IL-3, etc. activate or attract T cells, activated T cells secrete IL-2, tumor necrosis factor (TNF) beta and granulocyte-monocyte colony-stimulating factor ( GMCSF), especially IFN-1, further promotes lymphocyte migration and infiltration, and finally destroys basal cells, and basal cell liquefaction degeneration occurs. This process involves multiple factors and forms a chain reaction, eventually causing pathological changes of lichen planus. .

5. It has been reported that patients with lichen planus have a positive family history of 10.7%. Although the report is not completely consistent, it is different from normal controls, suggesting that the disease may be related to heredity.

6. The incubation period during the application of the drug to the rash is longer, with an average of 1 year. There are two mechanisms for its mechanism: the drug antigen binds to the epidermis and exposes the surface antigen on the basal cell keratinocytes or induces its expression, thereby initiating The immune response, the drug may also directly affect the immunocompetent cells and lead to the activation of T lymphocyte clones.

Lichen planus prevention

Limit drinking and stimulating diet, regularize life, eliminate mental stress, treat chronic lesions, control scratching and avoid hot water soap scalding.

Lichen planus complications Complications

Acute or subacute lichen planus may be secondary to erythroderma.

Lichen planus symptoms common symptoms rashes fever fever dream ring granuloma

Lichen planus has certain characteristics in clinical practice. Typical skin lesions are purple red or dark red cap needles to lentils-sized polygonal papules or patches, which can be self-resolved, accompanied by obvious itching, and have certain predilection sites. In middle-aged people, there are characteristic changes in histopathology, and some skin lesions with different manifestations have histopathological changes of lichen planus, so they are attributed to atypical lichen planus, which is documented in the medical literature of the motherland. The "purple wind" is similar, such as the "Criteria for the Rule of the Rule", the purple wind recorded: "French purple wind, from the skin purple spots, the skin of the skin,".

1. Typical lichen planus This disease is more common in adults, 30 to 60 years old is a good age, children and the elderly are rare, women are slightly more than men, typical skin lesions are purple or dark red, reddish brown hat needle to lentils mostly flat The pimples have a clear boundary and are covered with a thin, waxy luster of adhesive scales (Fig. 1, 2). Sometimes the central dimples are visible, or there are small angled plugs. The papules have gray-white spots and interlaced nets. Stripe, called Wickham pattern, is more clear when applied with liquid oil. The skin lesions are red spots when they first appear. After a few weeks, they form a purple-red papule, which can develop rapidly in a short period of time. Skin lesions can be fused to each other, and there are mossy patches of different sizes and shapes. There may be scattered rash around (Fig. 3, 4). In the acute phase, there is a linear homomorphic reaction. The rash can occur throughout the body, often symmetrical. Occurred, with limbs flexed, the medial side of the femoral, axillary, hip and waist are more common, the neck also occurs frequently, consciously itching, varying degrees, even severe itching, a few unconscious symptoms.

Mucosa can be affected, about 60% to 70% of patients with lichen planus have oral damage, which can occur simultaneously with skin lesions, and also occurs before or after the occurrence of skin lesions, some have only mucosal damage, oral lesions can be milky white spots, The spots are small and isolated, arranged in a ring shape, linear and irregular mesh, and may also have plaques, atrophy, papules, erosive ulcers and bullae. Aggressive ulcers are more common in the elderly and are prone to pain. Burning sensation, cheeks, gums, and tongue mucosa are the most frequently affected parts. The damage that occurs in the lips can be sticky scaly. It is very similar to the lip damage caused by lupus erythematosus. About 15% of male genitalia can be damaged. And penis is the most commonly affected part, often manifested as ring damage, female genital damage like mucosal leukoplakia and proliferative erythema, sometimes erosion, occasionally manifested as extensive desquamative vaginitis, damage to anal lichen planus There are mucosal leukoplakia, hyperkeratosis, fissures and erosion.

A can account for 10% to 15% of lichen planus. It is rare in cases of nails only. The deck is thin, and the mediastinum and distal cleft are the most common lesions. It can also be seen as a longitudinal fissure, hyperkeratosis, or even hyperkeratosis. The deck disappears, and the disappearance of nails can be caused by ulcerative lichen planus. The pterygium, which grows up in the back of the nail, and fuses with the adjacent nail bed, is a characteristic manifestation of the damage of the lichen planus, and the nail is more affected than the toenail. A lesion with lesions can occur simultaneously or sequentially, and the scalp can also be damaged. It is an erythema around the hair follicle and a follicular horn plug, one or more hair loss, and even permanent alopecia.

2. The lichen planus caused by the drug-induced lichen planus is injected, exposed to and inhaled a certain chemical substance, and the time of occurrence of the lesion is several months to one year after the administration of the drug, or longer, and the dose of the drug, the individual Sensitivity, exposure and drug usage, skin loss time is different, mostly for 3 to 4 months, the disappearance of moss-like rash caused by gold preparation may be 2 years after stopping the drug, the rash can be typical or atypical The expression of lichen planus is local or generalized eczema-like papules and plaques, irregular polygons, post-inflammatory hyperpigmentation, hair loss and loss of typical Wickham patterns, mostly in the trunk and limbs, and multiple symmetry The rash has less mucosal involvement. The course of the disease is chronic, lasting for several months to several years, most of them disappear in 1 to 2 years, oral damage can last for more than 20 years, and temporary pigmentation, hypopigmentation or atrophic scar remains.

3. The clinical manifestations of atypical lichen planus lichen planus are different. According to its incidence, rash morphology and different arrangement, there are many types. The common ones are listed below.

(1) Striped or linear lichen planus (lichen planus liuearis): the lesions are arranged in a line of varying lengths, often along the nerve segment or vascular path, sometimes occurring at the trauma or scratch, forming a homomorphic response It occurs on the side of the limbs, especially on the posterior side of the lower limbs, and sometimes extends over the entire limb (Fig. 5). It needs to be differentiated from linear moss, linear psoriasis, and linear sputum.

(2) Lichen planus annularis: about 10% of lichen planus, most of the rashes are arranged in a ring shape, or the rash is extended to the periphery, the edge is slightly elevated, the center is slightly concave or atrophic, and the damage may be present for a long time. Ring-shaped, common in the penis, glans (Figure 6), labia majora or oral mucosa, occurs in the trunk, the damage of the limbs can reach 2 ~ 3cm, the surrounding height, pigmentation, easy to be misdiagnosed as ring granuloma.

(3) Lichen planus verucosus: also known as lichen planus hypretrophicus, the rash has a scorpion-like appearance, which can be mostly plaque-like or hypertrophic, similar to chronic hypertrophic psoriasis. The surface is covered with gray-black fixed scaly, surrounded by polygonal flat papules. The sweat holes and pores at the skin lesions are often angled. After the removal, the depression is visible. This type is more common in the extension of the lower leg, and can also be seen on the extension of the upper limb. , wrist, item, buttocks and trunk (Figure 7), the elderly are more common, the course of disease is very long, constant years to decades of unhealed, after the damage subsided, leaving pigmentation and skin atrophy.

4. Atrophic lichen planus (lichen planus atrophicans) This type can be divided into two types: original hair style and secondary hair style. The original hair style is rare. The skin lesions are polygonal, the central atrophy, the hair follicle mouth and the sweat hole have a horn plug, and the atrophy Hypopigmentation, forming pale white spots, can be fused into large plaques, common in limbs and trunk, this type should be differentiated from morphea guttate, lichen sclero-siset atrophicus, Hairy people are more common in the process of regression of annular lichen planus or hypertrophic lichen planus. Histopathology shows that the epidermis and epidermal attachment are atrophied, the cell infiltration is less, and the infiltration zone is not obvious.

5. lichen planus bullous This type is rare, often present on the primary papules, plaques or normal skin blisters or bullae, the size of which is consistent with papules or plaques, the blister content is clear, there are In patients with blood blister, blisters can appear in the acute phase of lichen planus, with moderate discomfort, can disappear within a few months, skin lesions often occur in the lower limbs, oral mucosa can also appear bullous erosion, conscious pain, histology There is a typical lichen planus change. The clinical manifestations of bullae on normal skin are similar to pemphigus or herpetic dermatitis, but with typical lichen planus. Direct immunofluorescence at the bullous area has IgG, IgM in the basement membrane area. C3 deposition, circulating anti-basement membrane antibody in serum, mostly on the basis of acute generalized lichen planus, this type is rare, should be identified with pemphigus.

Lichen planus examination

1. Ask about the pathogenesis, symptoms, treatment and Helicobacter pylori (HP) infection in the digestive tract, and ask about the causes, such as mental factors, endocrine disorders, autoimmunity and infection.

2. Whether the characteristics of oral lesions are damaged by mesh, ring, dendritic or plaque formed by white fine lines or papules.

3. When inspecting, pay attention to the location, shape, color and surrounding mucosa of any lesions, such as congestion, erosion or blisters, and pay attention to the presence or absence of skin lesions.

4. If necessary, biopsy can be done, pay attention to the identification of erythema, and the lesions that have not been cured for a long time should be closely observed for cancer.

Lichen planus diagnosis

diagnosis

According to the characteristics of skin lesions, red to purple polygonal flat papules or large mossy patches merged into the surface, smooth and shiny waxy film and Wickham pattern on the surface, combined with histopathological features, diagnosis is not difficult.

Differential diagnosis

Atypical patients still need to be identified with the following diseases.

1. Neurodermatitis is mostly located in the neck, with significant bryophyte, no polygonal umbilical follicles, often consistent with skin color, no Wickham pattern, no damage to the mouth and nails.

2. Skin amyloid metaplasia occurs mostly in front of bilateral iliac crest, which is a slightly flat papule dense in contrast to mossy appearance, rough and dull surface, taupe or consistent with skin color, no Wickham pattern, Congo red test negative.

3. Psoriasis infiltration is remarkable, with multiple layers of silvery white scales. After peeling, the base can be seen as spotted hemorrhage without Wickham pattern.

4. Drug eruption Many drugs can cause lichen planus rash, but the drug rash is rapid, the site is extensive, and there is a clear history of medication. It is easy to cure after stopping the drug.

5. Hair red pityriasis has dry and hard miliary keratinized papules consistent with hair follicles. The back and hips of the fingers are more prominent, often accompanied by excessive keratosis of the palmar, and the nails are often involved.

6. Other oral mucosal damage should be differentiated from mucosal leukoplakia, the latter is precancerous lesions, the plaque is relatively hard, the boundary is clear, the surface color is uniform, often divided into most small pieces, with fine red lines, which can be cancerous. May be related to smoking, more common in middle-aged men, erosive and bullous should be differentiated from pemphigus vulgaris and polymorphous erythema, histopathological examination can confirm the diagnosis.

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