Overall, it is found that patients with erythematous or erosive oral lichen planus have a higher risk of oral squamous cell carcinoma compared to patients diagnosed with other variants.Due to the possibility that oral LP may increase risk for oral cancer, patients with oral lichen planus are encouraged to avoid activities known to increase the risk for oral cancer, such as smoking and alcohol use.Patients with oral lichen planus should be followed-up at least every 6 to 12 months, to assess the disease activity, changes in symptoms or even detect early signs of malignancy. Epidemiology
The overall estimated prevalence of lichen planus in worldwide population is in the range of 0.2% to 5%.It generally occurs more commonly in females, in a ratio of 3:2, and most cases are diagnosed between the ages of 30 and 60, but it can occur at any age.Lichen planus can occur in patients as diverse cutaneous manifestations alone or in combination with mucosal lichen planus and, or lichen planus of the nails. Study shows that frequency of mucosal involvement of lichen planus patients is 30- 70%.Oral lichen planus is relatively common, It is one of the most common mucosal diseases. The prevalence in the general population is about 1.27–2.0%, and it occurs more commonly in middle aged people. Oral lichen planus in children is rare.
Mucosal forms are those affecting the lining of the gastrointestinal tract (mouth, pharynx, esophagus, stomach, anus), larynx, and other mucosal surfaces including the genitals, peritoneum, ears, nose, bladder and conjunctiva of the eyes. Pattern
Lichen planus lesions can occur in many different forms:

Overlap syndromes
Occasionally, lichen planus is known to occur with other conditions. For example:

Lupus erythematosus overlap syndrome. Lesions of this syndrome share features of both lupus erythematosus and lichen planus. Lesions are usually large and hypopigmented, atrophic, and with a red to blue colour and minimal scaling. Telangectasia may be present. Lichen sclerosus overlap syndrome, sharing features of lichen planus and lichen sclerosus. Signs and symptoms
Although lichen planus can present with a variety of lesions, the most common presentation is as a well defined area of purple-coloured, itchy, flat-topped papules with interspersed lacy white lines (Wickhams striae). This description is known as the characteristic "6 Ps" of lichen planus: planar (flat-topped), purple, polygonal, pruritic, papules, and plaques. This rash, after regressing, is likely to leave an area of hyperpigmentation that slowly fades. That said, a variety of other lesions can also occur. Skin
Variants of cutaneous lichen planus are distinguished based upon the appearance of the lesions and/or their distribution. Lesions can affect the:

Extremities (face, dorsal hands, arms, and nape of neck). This is more common in Middle Eastern countries in spring and summer, where sunlight appears to have a precipitating effect. Palms and soles
Intertriginous areas of the skin. This is also known as "inverse lichen planus."