Introduction
Lichen Planus is a chronic, pruritic, papular skin disease. It has three cardinal features which include:
- Skin lesions
- Mucosal lesions
- Histopathologic features of band-like infiltration of lymphocytes and melanophages in the upper dermis.
Some of the drugs known to cause lichen planus (LP) are
- Chloroquine
- Quinacrine
- Quinidine
- Gold
- Streptomycin
- Tetracycline
- NSAIDS
- Phenothiazines
- Hydrochlorothiazide
Symptoms and clinical features of lichen planus
- Lichen Planus has been found in children, young and middle-aged adults
- The skin lesions are flat-topped polygonal papules with a characteristic colour
- Violaceous in fair skinned people but slate-grey on black skin
- Itching is mild-to-severe
- Like psoriasis, lesions often occur on sites of trauma and scratch marks (Koebner’s or isomorphic phenomenon)
- Wickham’s striae are fine white streaks present on the tops of papules
- The lesions are distributed mainly on:
- Flexor surfaces of the wrist
- Lumbar area
- The penis, tongue, buccal and vaginal mucous membranes
- On the buccal mucous membrane it may present as white reticulate pattern or plaque which may after several years transgress into squamous cell carcinoma
- The nails are also affected with:
- Pitting, roughening and splitting
- Thickening (pachyonychia) (trachyonychia)
- Encroachment of the nail fold on the nail plate (pterygium ungium)
- Total destruction of all 20 nails may precede, accompany, or follow the onset of skin lesions
- The hair follicles in the scalp may also be affected (lichen planopilaris) with post inflammatory scarring alopecia
- Hepatitis C infection is found with greater frequency in lichen planus than in controls
- Healing of the skin lesions leave post inflammatory hyperpigmentation
Differential diagnoses
Consider other papulosquamous disorders:
- Psoriasis
- Pityriasis rosea
- Lupus erythematosus
- Secondary syphilis
- Lichen striatus
- Parapsoriasis
- Pityriasis rubra pilaris
Nummular eczema Oral lesions:-
- Erosive lesions may mimic:
- Aphthous stomatitis and herpes simplex
- White plaques may be confused with Pre malignant leukoplakia
- White sponge naevus
Complications of lichen planus
- 20-nail dystrophy
- Rarely, squamous cell carcinoma of oral and hypertrophic lichen planus
Investigations
- Histopathology
- Hepatitis C antigen
Treatment for lichen planus
Treatment objectives
- Relieve itching
- Clear lesions
- Suppress inflammation
Drug treatment
Topical corticosteroids:
Beclomethasone dipropionate 0.1% cream
- Apply 1-2 times daily.
- Not licensed for use in children under one year
Bethamethasone valarate 0.1% cream and ointment
- Apply 1-2 times daily
- For isolated or hyperkeratotic lesions apply corticosteroids under occlusion or use intralesional triamcinolone
Scalp lesions:
Topical corticosteroids
Clobetasol propionate 0.05% lotion
- Apply thinly 1-2 times daily for up to 4 weeks
Mouth lesions:
Triamcinolone acetonide 0.1% in adhesive base
- Apply a thin layer 2 – 4 times daily for a maximum of 5 days; do not rub in
Or:
Tretinoin 0.025% cream
- Adult and child: apply thinly 1-2 times daily
Systemic corticosteroids
Prednisolone
- Adult: 20-40 mg orally daily for several weeks with reduction of dosage or switch to alternate-day therapy as soon as improvement is seen
- Child: not recommended for children for this indication
Or:
Triamcinolone acetonide 40 mg.
intramuscularly once or twice (at a 6-week interval)
Or:
Ciclosporin
- Adult and child over 16 years: 2.5 mg/kg daily in two divided doses. If good results not achieved within two weeks increase rapidly to maximum 5 mg/kg daily
Notable adverse drug reactions
- See Psoriasis
Prevention of lichen planus
- Avoid precipitating drugs