An inflammatory condition of the mucous membranes and skin with no recognized origin is lichen planus (LP). The lower back, wrists, & ankles are the most typical locations for its inflamed, violaceous plaques and papules and to form. Overlying the lesions is a lattice-like structure of white lines known as Wickham striae, which can also have erosions but is easiest to see on the buccal mucosal layer. Lichenoid medication eruption, also known as medication-induced LP, is commonly photographed but may be difficult to identify from idiopathic LP.

There are many differences in the natural history of LP. Most skin lesions in individuals spontaneously disappear within one to two years after early manifestation. However, relapses are frequent, and persistent skin darkening frequently follows. Oral LP, in contrast, is a persistent condition that might or might not go away. Medication-induced LP progressively goes away after the offending drug is stopped.

In adults around the world, cutaneous LP affects 0.2% – 1% of them. More frequently reported in 1% – 4% of the patients are oral LP. Overall, women are affected 1.5 times more commonly than males, and also most occurrences appear between the ages of thirty and sixties. Children make up fewer than 5 percent of all LP cases; thus, it is uncommon in them.

Although LP is generally thought not to have a racial bias, several recent research has revealed that African Americans and individuals of Indian & Arabian heritage may have a higher frequency of the condition. Given that up to 10 percent of first-degree family members of patients may also contract the illness, there does seem to be a familial element.

Idiopathic illness is lichen planus. Its pathophysiology is unclear; however, it seems to be a T-cell-mediated autoimmune condition. According to the predominant view, contact with an exogenous substance such as medication, virus, or allergy changes the epidermis self-antigens & activates cytotoxic CD8+ T – lymphocytes. T-cell targeted & death come from the changed self-antigens cross-reaction with the usual self-antigens on keratinocytes.

Numerous substances have been linked to the emergence of LP, but the connection with viruses, particularly the hepatitis C virus, has received considerable attention. Individuals with LP are five times more likely than the general population to test positive for HCV, and those who are already HCV-positive are 2.5 – 4.5 times more probable LP.

Contact sensitivities to certain metals, including copper, gold, and mercury, which are used in restorative dentistry, are linked to oral LP. It has been documented that removing the reactive metal clears the LP scars. Although a significant variety of medications have been linked to LP, it is uncommon for lesions to return after drug re-exposure. Antimalarials, thiazide diuretics, ACEIs, ß-blockers, quinidine, NSAIDs, gold, and TNF-alpha inhibitors are some of the medications that are more frequently related.

In one to two years, cutaneous LP frequently resolves on its own, but persistent hyperpigmentation is fairly prevalent. Oral LP may go away on its own within five years, but it usually has a chronic, remitting, & relapsing duration.

Permanent baldness results from LPP. Medication-induced LP scars gradually disappear if the offending medicine is stopped.

Lichen planus (LP) is typically an insidious condition. The flexural surfaces of the limbs, such as the wrists, are where lesions typically appear. A broad eruption begins to form after a week or longer, spreading most widely between two and sixteen weeks later. Lichen planus patients frequently have pruritus, however, the intensity of it varies depending on the lesion’s nature and degree of involvement.

Extremely itchy hypertrophic lesions are seen. If erosions are present, oral lesions may even be painful if they are asymptomatic, burning, or both. The lesions disappear in more than 50% of individuals with the cutaneous disease within 6 months, and in 85% of cases, they disappear within 18 months. Oral lichen planus, on the other hand, was said to have a mean lifespan of five years. Lesions that are large, annular, hypertrophic, and involve the mucosal membranes are more likely to develop chronically.

Lichen planus (LP) can affect the mucous membranes, genitalia, nails, and scalp in addition to the cutaneous eruption. Actinic (in sun-exposed areas), pigmented, atrophic, annular, follicular, erosive, linear, hypertrophic, & bullous/vesicular are some of the clinical manifestations of lichen planus. The polygonal papules are violaceous and glossy and range in size from 1 mm to more than 1 cm. They may be scattered or organized in sets of circles or lines. The papules frequently include Wickham stria, which is distinctive thin, white lines.

Involvement of the mucous membranes is frequent and can occur in patients without skin involvement. There are six different subtypes of oral LP: bullous, reticular, erosive, papular, plaque-like, and erosive. The most typical variety, reticular, manifests as asymptomatic white, lacy lines that are frequently visible on the contralateral buccal mucosa. The erosive and atrophic variants are frequently accompanied by a burning discomfort that is made worse by spiciness or hot foods.

The tongue & buccal mucosa are the most typically affected areas, and lesions are identified by white or grey stripes creating a linear and reticular design on the violaceous surrounding. Men may be more likely than women to have malignant changes of ulcerated oral lesions. However, this finding could be complicated by additional factors, including smoking & tobacco products. Other areas of the body where lesions can be identified include the gastrointestinal system, the anus, the larynx, the esophagus, the tonsils, the bladder, the vulva, and the vaginal vault.

The glans penis is the most prevalent location where LP manifests as an annular arrangement. Contrarily, in women, an erosive form is typically detected when LP affects the vulva or vagina, and problematic sequelae, including scarring and strictures, can develop. The vulvovaginal-gingival syndrome is the name given to LP that is simultaneously seen on the female genital and oral mucosa.

10% of patients will get LP of the nails, which commonly affects several nails without necessarily harming the neighboring skin. The initial symptoms of illness are longitudinal ridging and thinning of the nail plate. Continued involvement results in nail matrix scarring, dorsal pterygium development, trachonychia, and possibly complete nail plate loss. Twenty-nail dystrophy is a subtype of LP in which these abnormalities on all twenty nails are the only outward manifestations of the disease. Children are much more often than adults to have this subtype.

Lichen planopilaris is the name for lichen planus that affects the scalp and other hair-bearing areas (LPP). Where there is inflammation, little, red follicular papules and macules form, and they cause alopecia with gradual scarring. Frontal fibrosing alopecia is the term used to describe LPP in older women that primarily affects the eyebrows and anterior scalp. Graham-Little-Piccardi-Lasseur syndrome, a familial variation of LPP, is characterized by non-scarring pubic and axillary hair loss and follicular papules in addition to usual cutaneous or mucosal LP.

Lichenoid drug eruption commonly manifests in sun-exposed regions, is symmetric, and has a more widespread distribution than the conventional LP sites. A detailed assessment of medication history is essential to correctly diagnose drug-induced LP because there is generally a latent period of many months to a year between the use of a drug and the development of lesions.

Differential Diagnoses

Tinea Corporis

Plaque Psoriasis

Pityriasis Rosea

Pediatric Syphilis

Lichen Simplex Chronicus

Lichen nitidus

Guttate Psoriasis

Symptoms of Graft versus Host Disease in the Skin

The goal of treatment for cutaneous LP is to lessen pruritus and shorten the time it takes for the condition to resolve, which normally takes one to two years. Clobetasol 0.05% (topical steroids) twice daily for two to four weeks are the initial line of treatment for restricted LP. Intralesional steroid infusions (triamcinolone 5–10 mg/mL) may be used to improve an inadequate reaction to topical treatments. For diffuse LP, oral corticosteroids like prednisone 30 to 60 mg tapered over two to six weeks are the first line of treatment. Second-line treatment should be tried if no improvement is noticed.

In the second line of treatment, patients may receive metronidazole (500 mg twice daily for 3 to 8 weeks), sulfasalazine – 500 mg twice daily, acitretin – 30 mg daily for eight weeks, isotretinoin – 10 mg twice daily for two months, UVB, PUVA, topical calcineurin blockers, and methotrexate – 0.25 mg/kg per week for children and 15 mg per week for adults.

Third-line therapy may include trimethoprim-sulfamethoxazole, antimalarials, griseofulvin, terbinafine, ciclosporin, mycophenolate mofetil, tetracyclines, etanercept, azathioprine, low-molecular-weight heparin, or adalimumab. Within five years, oral LP may spontaneously resolve, but many instances are chronic and do not resolve. The common outcome of remission triggered by treatment is recurrence. As a result, silent oral LP shouldn’t be treated due to the significant risk of side effects.

In order to relieve discomfort and restore normal food intake, erosive lesions in the mouth must be healed during therapy of symptomatic oral LP. Individuals should be advised to stay away from foods that are hot and acidic, in addition to alcohol & smoke, as these things aggravate symptoms. Very potent topical steroids are the first line of treatment and are used 3 times a day till remission. If there is no progress after six weeks, therapy should be intensified.

Oral steroids or the use of cutaneous calcineurin blockers are second-line therapies. Third-line therapy may include azathioprine, mycophenolate mofetil, methotrexate, or cyclosporine. Prior to beginning treatment, medication-induced LP should always be researched. The diagnosis is confirmed by stopping the suspected medicine and watching the lesions gradually fade away, however it could take some time for the lesions to completely go away.

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https://www.ncbi.nlm.nih.gov/books/NBK526126/