1. Typical lichen planus is more common in adults, the most common is 30-60 years old, and it is rare in children and the elderly, with slightly more females than males. Typical skin lesions are purplish red or dark red, reddish brown polygonal flat papules, ranging from hat needles to lentils, with clear boundaries. The surface is covered with a thin layer of attached scales, which has a waxy luster (Figure 1 2), sometimes the center is slightly concave, or there are tiny corner plugs. The surface of the papules has gray spots and staggered reticular stripes, which are called Webster's stripes, which are more obvious after being wiped with liquid oil. The skin lesions started as red spots and formed purple papules several weeks later. Sometimes it can develop and spread rapidly in a short time. Skin lesions can merge with each other, showing lichenoid patches of different sizes and shapes, with rashes scattered around them (Figures 3 and 4), and linear isomorphic reactions appear after scratching in the acute stage. Rash can occur in all parts of the body, often symmetrical, especially in the flexion side of limbs, inner thighs, internal fossa, buttocks and waist, and also in the neck. Conscious itching, varying degrees, even severe itching, a few have no conscious symptoms.
Mucosa may also be involved. About 60% ~ 70% patients with lichen planus have oral lesions, which can occur at the same time as skin lesions, before or after skin lesions, and some only have mucosal lesions. Oral lesions can be milky white spots, small and isolated spots, arranged in a ring, line and irregular network, or plaques, atrophy, papules, erosive ulcers and bullae. Erosive ulcer is more common in the elderly, which is easy to cause pain and burning sensation. Buccal mucosa, gingival mucosa and tongue mucosa are the most commonly involved parts. The lip injury may have adhesive scales, which is very similar to the lip injury caused by lupus erythematosus. About 15% of male genitalia can be damaged, and the glans penis and penis are the most commonly involved parts, which are often damaged in a ring shape. The damage of female external genitalia, such as mucosal leukoplakia and proliferative erythema, is sometimes accompanied by erosion and occasionally by extensive desquamation vaginitis. The pathological changes of anal lichen planus can include mucosal leukoplakia, hyperkeratosis, fissure and erosion.
Nail involvement can account for 10% ~ 15% of lichen planus, and only cases of nail involvement are rare. Deck thinning, longitudinal ridge and far crack are the most common damages, and longitudinal nail crack, hyperkeratosis under nail and even deck disappearance can also be seen. The disappearance of nails can be caused by ulcerative lichen planus. The pterygium of nail, that is, the fold of nail back grows upward and merges with the adjacent nail bed, which is the characteristic manifestation of lichen planus nail damage. Nails are more complicated than toenails, and pathological nail injuries can occur simultaneously or successively. Scalp can also be damaged, such as erythema around hair follicles and hair follicle angle plugs, one or more hair loss, and even permanent hair loss.
2. Lichen planus caused by drug-induced lichen planus occurs after injection, contact and inhalation of a chemical substance. The appearance time of skin lesions varies from several months to 1 year, or longer, which is related to the dosage, individual sensitivity, exposure and usage of drugs. The regression time of skin lesions varies from 3 to 4 months, and the regression of lichenoid rash caused by gold preparation may take 2 years after drug withdrawal. Rash can be a typical or atypical manifestation of lichen planus, characterized by localized or generalized eczema-like papules and plaques, irregular polygons, post-inflammatory pigmentation, alopecia and typical Wickham line loss, which mostly occur in trunk and limbs, as well as multiple symmetrical rashes. Mucosal involvement is less.
The course of the disease is chronic, lasting for several months to several years, and most of them spontaneously subside within 1 ~ 2 years. Oral injury can last for more than 20 years. Temporary pigmentation, hypopigmentation or atrophic scar are left after healing.
3. The clinical manifestations of atypical lichen planus are different, and there are many types according to its incidence, rash shape and arrangement. Common examples are as follows.
(1)lichenoplanus Liu earis: Lesions are arranged in lines with different lengths, often distributed along ganglion segments or vascular pathways, and sometimes occur in trauma or abrasions, forming isomorphic reactions. It mostly occurs on one side of the limb, especially on the back side of the lower limb, and sometimes it can spread to the whole limb (Figure 5). It should be differentiated from linear lichen, linear psoriasis and linear mole.
(2) Lichen planus: It accounts for about 10% of lichen planus. Rashes are mostly arranged in a ring, or extend around, with slightly raised edges and slightly depressed or atrophied centers. When damaged, it can be annular, which is common in penis, glans penis (Figure 6), labia majora or oral mucosa. The lesions in trunk and limbs can reach 2 ~ 3 cm in diameter, with high periphery and pigmentation, which is easy to be misdiagnosed as annular granuloma.
(3)lichenoplanusverucosus: also known as lichenplanushypretrophicus. The appearance of the rash is verrucous, mostly clustered or flaky hyperplasia, similar to chronic hypertrophic psoriasis. The surface is covered with gray-black fixed scales, surrounded by scattered polygonal flat papules. There are angle plugs in the sweat holes and pores of the skin lesions, and depressions can be seen after removal. This type is more common in the extended side of the calf, but also in the extended side of the upper limbs, thighs, wrists, neck, buttocks and trunk (Figure 7). It is more common in the elderly, and the course of disease is long, and it remains unchanged for several years to decades. After the injury subsided, pigmentation and skin atrophy still existed.
4. Bacillus licheniformis can be divided into primary type and secondary type. The original hairstyle is rare, the skin lesions are polygonal, the center is atrophied, there are angle plugs at the hair follicle mouth and sweat pores, which atrophy into hypopigmentation, forming pale white spots, which can be fused into large patches, and are common in limbs and trunk. This type should be differentiated from macular leukoplakia and lichen sclerosus dystrophy. Secondary cases are more common in the process of regression of annular lichen planus or hypertrophic lichen planus. Histopathology showed that epidermis and epidermal appendages were atrophied, with less cell infiltration and no obvious infiltration zone.
5. Lichen-like bullae are rare. Bullets or bullae often appear on primary papules, plaques or normal skin, and the size is consistent with papules or plaques. Lichen planus may appear in acute stage with clear contents and occasional bloody blisters, accompanied by moderate discomfort, and disappear within several months. Skin lesions often occur in lower limbs, and oral mucosa may also have bullous erosion and conscious pain. Histologically, there are typical lichen planus-like changes. The clinical manifestations of bullae on normal skin are similar to pemphigus or herpetic dermatitis, but there are typical lichen planus tissues. Direct immunofluorescence examination at the bulla showed that IgG, IgM and C3 were deposited in the basement membrane area, and circulating anti-basement membrane antibodies were found in serum. Most of them are based on acute generalized lichen planus. This type is rare and should be differentiated from pemphigus.
6. Lichen planus, also known as lichen planus, is more common in adult women. Can be isolated from hair follicles or other skin and mucosal lesions with lichen planus. The lesions are obvious hair follicle papules and nut-like plaques, which can form atrophic scars after long-term hair loss. In addition to the scalp, it is common in the neck, scapula, chest and the outside of limbs. Follicular lichen planus of skin and/or scalp, cicatricial alopecia of scalp and non-cicatricial alopecia of axilla and pubis are called Graham-Little-Picardi-rasul triad. Histopathology: In addition to the typical lichen planus histopathology, the hair follicle corner plug can be seen, and the hair follicle root infiltration is significant. This type should be differentiated from follicular keratosis, tuberculous lichen and discoid lupus erythematosus.
7. Photosensitive lichen planus is also called subtropical lichen planus. Lichen planus, actinic lichenoid eruption in summer, etc. This type is relatively rare, more common in children and adolescents, and is related to sun exposure. It often happens in spring and summer in Middle Eastern countries. Common in the forehead, neck, arms, forearms, lower lip and upper chest, but also in mucous membranes and other parts of the body. In addition to the typical lichen planus lesions, there are also pigmentation or hypopigmentation plaques, or light brown, purple-blue round and oval plaques with obvious boundaries, convex edges and sunken centers. Self-conscious symptoms are mild and can itch slightly in summer. Some people think it is a kind of lichen planus annulata, or it is the same disease as actinic granuloma. It should be differentiated from discoid lupus erythematosus and solar dermatitis.
8. Lichen planus of palmoplantar moss is rare. The lesions mostly occurred in the palmoplantar margin, which was asymmetrical and lacked the characteristics of lichen planus. It is characterized by keratinized patches or plaques, hard texture, obvious and rough surface keratinization, callose or punctate keratinization, and no conscious symptoms. If there is lichen planus in other parts of the body, it is easy to diagnose. This disease occurs in the heel, which can form bullae, and often produces ulcers due to friction stimulation, which is called foot ulcer lichen planus. Oral mucosa can also be involved at the same time, and the fingernails can fall off permanently. It should be differentiated from callus, plantar wart and palmoplantar psoriasis.
9. Acute or subacute lichen planus has an acute onset and obvious inflammation. At first, it was mostly red papules, then the skin gradually turned purple, and it could be grayish brown after fading. Often appear in batches, which can involve the skin, and the skin is red and swollen, and sometimes blisters or bullae can appear. Typical lichen planus lesions can be seen around 4 weeks, with severe itching. Severe cases may be accompanied by systemic symptoms such as fever and discomfort, and even secondary erythroderma. This type should be differentiated from drug eruption of lichen planus.
10. There are many other clinical manifestations of lichen planus, in addition to the above, there may also be rosary (arranged like rosary, more common in face, neck and other parts of the body); Blunt (large rash, few in number, flat or dome-shaped, more common in limbs); Isolated (isolated, pigmented nevus, mostly in upper limbs) and so on.
According to the characteristics of skin lesions, red to purple polygonal flat papules or large moss patches with smooth and shiny wax film and wickham lines on the surface, combined with histopathological characteristics, the diagnosis is not difficult.
TCM pathogenesis and syndrome differentiation;
1. Chinese medicine believes that yin and blood in the body are insufficient, spleen is wet and healthy, dampness is blocked, wind and evil are resumed, rheumatism is in the skin, and blood stasis is in the blood; Or due to deficiency of liver and kidney, internal heat due to yin deficiency, and inflammation due to deficiency of fire.
2. TCM syndrome differentiation and classification
(1) Rheumatism stagnation type (occurring in the skin):
Main symptoms: the skin is maculopapular, or fused into pieces, or banded, with purple, smooth and itchy surface. The mouth is not thirsty, and women have more leucorrhea. Red tongue, fat body, thin white or slightly greasy tongue coating, slow pulse.
Syndrome differentiation and classification: rheumatism accumulation, meridian obstruction.
(2) Inflammation caused by deficiency fire (occurring in oral cavity):
Main symptoms: oral rash, milky white, or erosion. Often accompanied by dizziness, dreaminess, memory loss, sharp red tongue edge, thin white fur and slow pulse.
Syndrome Differentiation: Yin deficiency of liver and kidney, deficiency of fire.