It is characterized by the formation of flat topped, polygonal, greyish white, purple/iliac eruptions. Its surface is scaly, and is traversed by fine white lines, ‘Wickham's striae' which become prominent after the application of an emolient. The papules may coalesce to form plaques. The papules may scattered or grouped. They may be linear over the marks of excoriation or trauma (Koebner's phenomenon). They tend to involve the flexer surfaces of the wrist and forearms, lumbar area, ankles, glans penis, anterior aspect of lower legs, and the dorsal surfaces of the hands.Mucosoal surfaces are involved in nearly half the patients. The buccal mucosa and the tongue are most frequently affected but the lips, gums, palate, conjuntivae, larynx, genitalia, and gastrointestinal tract may also be involved. The mucosal lesions consists of lacy, reticulated, white streaks, papules, plaques, and erosions. Chronic erosive oral lichen planus may predispose to squamous cell carcinoma. Nearly 25 percent of the male patients have involvement of the genitalia. Lesions are often present over the glans and these may be typical papules in an annular configuration. Nails are affected in 10 percent of the cases and the changes include;• Thinning of the nail plate• Longitudinal ridging and splitting• Subungual hyperkeratosis• Onycholysis• Red or brown discoloration of the nail plate• Pterygium, a hallmark in lichen planus. It results from the fusion of the proximal nail fold with the nailbed resulting in the losss of proximal nail plate.Acute lichen planus usually resoves in 6 to 18 months. The lesions heal leaving behind hyperpigmentation which may take years to resolve.Lichenplanus may manifest as any of the following variants.Annular lichen planus It results in a ring of typical lichen planus papules that spread peripherally and produce central clearing.Linear lichen planus It consists of typical lichen planus lesions in a linear fashion. Occasionally, it may be in a zosterifrm distribution.Hypertrophic lichen planus (lichen verrucosus) It arises on the shins, ankles, and soles. It consist of intensely pruritic, lichenified, scaly, violaceous, verrucous hyperpigmented plaques. The lesions are often symmetric and chronic.Atrophic lichen planus It may occur over the mucous membranes. Atrophic lichen planus may produce atrophic white spots which need to be differentiated from lichen sclerosus et atrophicus and gutate morphea.Vesiculobullous lichen planus It may arise on pre existing lichen planus lesions or de novo. It is the result of sepration at the dermoepidermal junction secondary to basal cell degeneration. Lichen planus actinicus This variant is usually encountered in tropics, on sun-exposed areas. Lesions are pigmented, dyschromic or granuloma annulare like and only mildly pruritic.Lichen planus erythrematosus It is observed in older patients and consists of nonpruritic, soft, red papules, usually located on the forearms.Lichen planopilaris It presents as acuminate, hyperkeratotic, follicular papules, primarily on the scalp. The affected area may also depict scaling. Alopecia with atrophy may supervene.