Lichen planus is a chronic, inflammatory, pruritic skin condition. It is characterised by an itchy papular rash commonly on the palms, soles, genitalia, or flexor surface of the arms. It is a T-cell-mediated autoimmune disorder. The diagnosis is clinical.
It affects adults over 40-years-old. It is more common in women.
Subtypes of lichen planus
| Subtype | Description |
|---|---|
| Hypertrophic | Painful and often occurs on mucosal surfaces |
| Erosive or Ulcerative | Painful and often occus on mucosal surfaces |
- Causes
- Genetic predisposition
- Physical and psychological stress
- Skin trauma (occurs post-surgery or at sites of herpes zoster infection)
- Contact dermatitis
- Signs and symptoms
- Pruritic papular rash on the palms, soles, genitalia, or flexor surfaces
- Polygonal in shape
- βWhite-linesβ pattern on the surface (Wickhamβs striea)
- Koebner phenomenon (new lesions at the site of trauma)
- Oral involvement (50%) tends to be resistant to treatment.
- Evolve into brown macules as they heal
- Thinning of the nail plate and longitudinal ridging
- Pruritic papular rash on the palms, soles, genitalia, or flexor surfaces
- Differentials
- Lichenoid drug eruption: gold, hydroxychloroquine, quinine, captopril, and thiazides
- Eczema
- Psoriasis
- Candidiasis
- Lichen sclerosis
- Pemphigus
- Sarcoidosis
- Basal cell carcinoma
- Investigations
- Biopsy
- Saw-tooth pattern of epidermal hyperplasia
- T-cell infiltration of the dermis
- Reduced melanocytes
- Globular deposits of IgM or IgG/IgA on direct immunofluorescence
- Biopsy
- Treatment
- Potent topical steroids
- Benzydamine mouthwash or spray (for oral lichen planus)
- Oral steroids (for extensive lichen planus)
- Immunosuppressive therapy, e.g., azathioprine, mycophenolate, or hydroxychloroquine (for extensive lichen planus)
- Complications
- Hyperpigmentation
- Oral squamous cell carcinoma (1% lifetime risk)
- Carcinoma of the vulva
