Lichen planus

Lichen planus is an eruption characterized in its most typical form by pruritic polygonal purple papules. These small flat-topped papules typically show a white lacy network on their surface, Wickham's striae.
Lesions of lichen planus will develop at sites of trauma, the Koebner phenomenon.

• Hypertrophic lichen planus: Nodularity develops in areas of typical lichen planus. Hypertrophic lichen planus is particularly common on the lower extremities.



• Bullous lichen planus: Blisters occur in areas of extensive involvement



• Lichen planopilaris: Lichen planopilaris is a follicular lichen planus. The result is a scarring alopecia, with destruction of the scalp hair follicles.



• Actinic lichen planus: Most common in subtropical areas, lesions appear as patches and plaques in sun damaged skin.



• Annular lichen planus: Annular lesions, in the absence of typical lichen planus papules, can occur alone in this variety.



• Lichen planus of the mucous membranes: Lichen planus of the mucous membranes is very common in typical lichen planus. It can also occur in the absence of non mucous membrane lesions.
The oral changes are characteristically erythema with a reticulate lacy pattern on the buckle mucosa. Erosions may also be present. The entire oral cavity may be involved, as can the genitalia of men and women.


• Lichen planus of the nails: Lichen planus of the nails can occur alone, or in association with other types of lichen planus. The characteristic nail changes are marked thinning of the nail plate, enhancement of longitudinal lines, and pterygium formation. Indeed there may be destruction of the nail completely. All twenty nails can be affected.



• Lichen nitidus: Lichen nitidus can occur alone, or in the presence of typical lichen planus.
Pinpoint shiny papules, often grouped, can appear anywhere on the body. They may be asymptomatic, or pruritic. Biopsies show a characteristic lichenoid pattern.


• Lichen planus secondary to drug reactions: Lichen planus like eruptions secondary to drugs is a common cause of severe lichen planus. Gold, antimalarials, thiazides, beta-blockers, and captopril, are relatively common causes.

Treatment:

• It is important to avoid trauma in patients with lichen planus.
• If drug related, discontinuing the drug will usually result in clearing, although the process may take many months.
• Idiopathic lichen planus is a chronic condition that typically will remit, but only after years or decades.
• The treatment of choice for lichen planus of the skin is the application of a potent topical steroid such as clobetasol 0.05% cream BID. Topical steroids alone will control the problem in most patients.
• Oral lichen planus may respond to a topical steroid in an ointment base.
• Systemic therapy is rarely needed, but severe generalized lichen planus of the skin or mucous membranes responds very well to cyclosporine 2-5 mg/kg/day for 2-4 months.
• Failure to respond to cyclosporine is uncommon, but should that occur, other agents, such as systemic glucocorticoids, can produce a significant improvement in these patients.
• Liver disease may be linked to this including hepatitis C and HIV infection

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