Core Dermatology Diagnoses / CategoriesInflammatory

Lichen planus

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Publish date: Posted on
Last updated: October 21, 2023

Keywords #

lichen planus
lichenoid dermatoses
lichenoid reaction

Diagnosis #

Lichen planus (LP) is a rare autoimmune skin condition most commonly affecting middle-aged adults.[4]LP can affect the skin, nails, and mucous membranes. The etiology is not yet well understood, however LP is associated with an immune-mediated proliferation of CD8+ T lymphocytes against basal keratinocytes and other mediators of the Th1 immune response.[5]While many factors may trigger an autoimmune response in LP, hepatitis C infection and medications are the most commonly identified triggers.[5]Most cases of LP do not have a known cause or trigger.

Key Concepts #
  • Lichen planus is a chronic autoimmune disease of the skin and mucous membranes.
  • Hepatitis C infection is associated with lichen planus in some patients.
  • The classic skin findings are violaceous, pruritic, polygonal, papules and/or plaques, but many variants of LP exist.
  • LP can affect hair, nails, and mucous membranes.
  • Histological findings are mostly consistent across the many variants of LP.
  • Treatment involves high-potency topical corticosteroids or calcineurin inhibitors but may include oral systemic drugs for severe cases.
Epidemiology #

Epidemiology of LP is not well-defined but is estimated to affect up to 1% of the population.[5]Cutaneous lichen planus occurs most often in adults between the ages of 30 and 60 years old, and rarely occurs in childhood ages.[6]

Clinical Features #
  • The classic clinical features of cutaneous LP are commonly remembered as the 5P’s: Pruritic, Purple or violaceous, Polygonal, Planar, Papules or plaques.
  • Individual papules may be a few millimeters wide and are typically demarcated with sharp borders.[6]
  • Multiple papules may also but combine to form larger scaly plaques.
  • Fine white lines, referred to as “Wickham’s striae” may be observed on close inspection of these lesions.
  • Involvement of the nails occurs in approximately 10-25% of patients with lichen planus.[3] Clinical features may include longitudinal ridges or fissures, nail plate thinning, scarring, and permanent nail dystrophy.
  • Oral lichen planus presentation includes red, painful lesions that have a net-like white pattern (also termed Wickham’s striae), occurring most often along the buccal mucosa, and causing symptoms of pain, burning, or metallic taste in the mouth.[1,3]
Differential Diagnoses #
Diagnostic Workup #

Lichen planus may be diagnosed clinically by the observation of the classic polygonal papules in the presence of the other common features of LP. If the diagnosis is uncertain, a skin biopsy for routine histopathology may be performed. In patients with oral LP, biopsy for direct immunofluorescence (DIF) can help confirm lichen planus and exclude other causes of oral ulcers such as pemphigus vulgaris, recurrent aphthous ulcers and mucous membrane pemphigoid. Histopathology will demonstrate hyperkeratosis without parakeratosis and circumscribed wedge-shaped hypergranulosis.[6]Lymphocytic infiltration and vacuolar degeneration present at the dermal-epidermal junction are other classic histopathologic features.[6]

Treatment #

There are topical and systemic treatments available depending on the severity of the disease. Topical corticosteroids of intermediate and/or high potency(triamcinolone dental paste, dexamethasone elixir, fluocinonide or clobetasol gel and others) and calcineurin inhibitors such as tacrolimus and pimecrolimus are considered first line therapy for localized skin lesions primarily or in adjunct to systemic therapy.[2]Systemic oral glucocorticoids may also be used for refractory cases but should be reserved for an acute exacerbation, severe or widespread lesions. Many other systemic therapies exist, many of which act to suppress specific regulatory cells of the immune system.[2]Some examples include mycophenolate mofetil, hydroxychloroquine, methotrexate, cyclosporine, azathioprine and others.

Slide Viewer #
https://utahderm.med.utah.edu/image-viewer/
References #
  1. Gorouhi, F., Davari, P., & Fazel, N. (2014). Cutaneous and Mucosal Lichen Planus: A Comprehensive Review of Clinical Subtypes, Risk Factors, Diagnosis, and Prognosis.The Scientific World Journal,2014, 1–22. doi: 10.1155/2014/742826
  2. Husein-ElAhmed, H., Gieler, U., & Steinhoff, M. (2019). Lichen planus: a comprehensive evidence-based analysis of medical treatment. J Eur Acad Dermatol Venereol. doi:10.1111/jdv.15771
  3. Langner, A., & Chris, H. (2018, September 10). Lichen Planus. Retrieved May 12, 2020, from https://rarediseases.org/rare-diseases/lichen-planus/
  4. Nagao, Y., et al. (2017). Genome-Wide Association Study Identifies Risk Variants for Lichen Planus in Patients With Hepatitis C Virus Infection. Clin Gastroenterol Hepatol, 15(6), 937-944 e935. doi:10.1016/j.cgh.2016.12.029
  5. Tziotzios, C., et al. (2018). Lichen planus and lichenoid dermatoses: Clinical overview and molecular basis. J Am Acad Dermatol, 79(5), 789-804. doi:10.1016/j.jaad.2018.02.010
  6. Wagner, G., Rose, C., & Sachse, M. M. (2013). Clinical variants of lichen planus. J Dtsch Dermatol Ges, 11(4), 309-319. doi:10.1111/ddg.12031
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