- Clinical science
Lichen planus is a chronic inflammatory disease of unknown origin that is characterized by different types of lesions involving the skin and mucosa in middle-aged individuals. The most common lesions are purple papules with well-demarcated, irregular borders, which typically occur on the wrists, lower extremities, and genitoanal region. The surfaces of the lesions often exhibit a pattern of white lines known as Wickham's striae. The disease is diagnosed clinically, but may be confirmed through dermoscopy and punch biopsies. Biopsy also helps detect squamous cell carcinoma, a possible complication of genital lichen planus. Treatment primarily consists of high-dose topical steroids, but may also include oral steroids and phototherapy in cases of extensive or steroid-refractory disease.
- Prevalence: < 1%
- Age of onset: 30–60 years
Epidemiological data refers to the US, unless otherwise specified.
Lichen planus may affect the skin, mucosa, scalp, genitalia and nails, and presents with varying symptoms depending on the subtype of the disease. The condition is chronic and usually manifests with several relapses.
- Primary lesion
- Affects the extremities, especially the ankles and flexor wrists; trunk
- Lesions arranged in linear or circular groups; may coalesce into larger plaques
- Bilateral, symmetrical distribution
- Manifests with the
- May occur simultaneously with other subtypes
- Oral lichen planus
- Esophageal lichen planus
The 5 P's of lichen planus: Pruritic, Polygonal, Planar (flat-topped), Purple papules, and Plaques!
Lichen planus is clinically diagnosed based on the presence of typical skin lesions. Additional testing is performed to confirm the diagnosis and rule out other diseases.
- Punch biopsy
- Dermoscopy: detection of Wickham's striae
- Endoscopy: detection of esophageal involvement (erosions, plaques, inflamed mucosa)
Lichen sclerosus (et atrophicus)
- Definition: Lichen sclerosus is a chronic inflammatory disease with characteristic white, atrophic plaques.
- Etiology: unknown; but genetic, immunological and hormonal factors likely play a role
- Epidemiology: : rare disease; more common in women (postmenopausal)
- Clinical presentation
- Increased risk of cancer (squamous cell carcinoma);
- Destructive scarring
- Drug-induced lichen planus (lichenoid drug eruption)
- graft-versus-host disease) (
- psoriasis and plaque psoriasis) (guttate
The differential diagnoses listed here are not exhaustive.
- First-line therapy
- Second-line therapy
- Adjunctive therapy: oral antihistamines (e.g., hydroxyzine) to manage pruritus