Lichen ruber planus.
1.5.4 Lichen planus
Synonyms
Epidemiology
Prevalence between 0.1 to 4%, with most cases occurring between 30 to 60 years of age, and with a slight predominance in perimenopausal women.
Definition
Idiopathic subacute to chronic inflammatory dermatosis involving the skin, mucosae, nails and/or hair.
Aetiology & Pathogenesis
Very likely to be an autoimmune disorder, associations with collagen-vascular diseases, vitiligo and diabetes mellitus. Graft-versus-host-disease (GvHD) has similar morphology. Hepatitis B and C, stress and various drugs may also play a role in its induction.
Signs & Symptoms
- Skin: polygonal violaceous papules, white net-like superficial markings (Wickham's striae), marked pruritus; Köbner phenomenon.
- Mucosae: lips, tongue, cheeks, genital and anal areas (annular, bullous, erosive, atrophic), net-like white, non-removable pattern.
- Nails: nonspecific changes (longitudinal stripes), nail dystrophy, nail matrix destruction.
- Scalp: lichen planopilaris, atrophic scarring alopecia.
- Palmoplantar: hyperkeratosis and fissures.
Localisation
More commonly flexor aspects of wrists, nails, oral and genital mucosae; can be disseminated.
Classification
Various types: localized, exanthematous, mucosal.
Laboratory & other workups
None specific.
Dermatopathology
Acanthosis, saw-toothed dermal-epidermal junction profile, hypergranulosis, subepidermal interface band-like infiltrate of T lymphocytes, pigment incontinence.
Course
Lichen planus of the skin often resolves after a few months or years, although it may recur. If caused by medication or tooth fillings, lichen planus will clear after the treatment is stopped or the fillings removed. Lichen planus of the mucosa, nails, and scalp rarely clears by itself and can cause permanent scarring.
Complications
Erosive lichen planus of the mucosae can lead to squamous cell carcinoma, making follow-up essential.
Diagnosis
Clinical features, histology, Köbner phenomenon.
Differential diagnosis
Lichenoid drug reactions: Skin eruptions caused by commonly used medications can resemble lichen planus. Quinine in tonic water and over-the-counter leg cramp medicines can cause a lichen planus–like condition. In the mouth, allergy to the metals in fillings and oral appliances can cause sores that look exactly like oral lichen planus.
Prevention & Therapy
Prevention: Avoid/control predisposing factors.
- Topical: high potency corticosteroids, calcineurin inhibitors (mucosal involvement), tazarotene, calcipotriol, UVA/B, PUVA, UVA1.
- Systemic: corticosteroids, PUVA, dapsone, hydroxychloroquine, methotrexate, mycophenolate mofetil, acitretin, alitretinoin, ciclosporin, azathioprine, apremilast, sedatives.
Special
TNF blockers exhibit fairly controversial effects in lichen planus, since they can trigger proinflammatory reactions.
Differential Diagnosis
Podcasts
Tests
- True or false?
- Which diseases are often associated with lichen planus?
- Which therapy is indicated for lichen planus?
- Statement 1 Regular use of sunscreens is an important part of the therapy for lichen planus
- Statement 1 Lichen planus is a dermatologic emergency and must be treated in the hospital
- Which of these diseases does not enter into the differential diagnosis of lichen planus?
- Which of these histological signs suggests lichen planus?
- Which clinical description is typical of lichen planus?
- Which statement regarding lichen planus is false?
Further Images / DOIA
Review Articles
- C. Tziotzios, J.Y.W. Lee, T. Brier, et al.: Lichen planus and lichenoid dermatoses: Clinical overview and molecular basis (2018)
- C. Tziotzios, J.Y.W. Lee, T. Brier, et al.: Lichen planus and lichenoid dermatoses: Conventional and emerging therapeutic strategies (2018)
- L. Le Cleach, O. Chosidow: Lichen Planus (2012)
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