Lichen Planus is one of the lichenoid dermatoses.
Features of Lichen Planus
- Itchy
- Violet
- Polygonal
- Flat topped papules
- Lacy white lines -> Wickham’s Striae
- Papules clear and replaced by brown discolouration
- Lesions anywhere – most common on the front of the wrists, flexor aspects of the forearms, genitals, lumbar region and the ankles and shins;
- mucous membranes commonly affected – Classically, white slightly raised lesions with a trabecular, lacy appearance on the inside of the cheeks.
Causes of Lichen Planus
T cell-mediated autoimmune disease
Contributing factors to lichen planus may include:
- Genetic predisposition
- Physical and emotional stress
- Injury to the skin; lichen planus often appears where the skin has been scratched—isomorphic response (koebnerisation)
- Localised skin disease such as herpes zoster—isotopic response
- Systemic viral infection, such as hepatitis C (which might modify self-antigens on the surface of basal keratinocytes)
- Contact allergy, such as to metal fillings in oral lichen planus (rare)
- Drugs; gold, quinine, quinidine and others can cause a lichenoid rash
Types of Lichen Planus
- Skin
- Oral
- Vulval
- Nails
- Pigmentosus
- Lichenoid drug reaction
Treatment of Lichen Planus
- Refer to dermatology
- Topical or oral CS by dermatologist – moderately potent or intralesional
- Sedating antihistamines for itch
- Occlusion with potent or super potent CS for persistent lesions
- Extensive with 20mg pred daily 14 days
- Phototherapy – PUVA
- Acitretin
- Isotretinoin
Complications of Lichen Planus
- Small risk of malignant change
- SCC
- Residual hyperpigmentation
(This brief explanation concentrates on only dermal and oral Lichen Planus, and doesn’t go too far into the subtypes)
