ABSTRACT
White patches may be divided into those that are painless and those that may be painful (Table 3).
ETIOLOGY AND PATHOGENESIS Lichen planus is one of the more frequently occurring mucocutaneous disorders. The cause of lichen planus is not known, although it is immunologically mediated and resembles, in many ways, a hypersensitivity reaction. T-lymphocytemediated destruction of basal keratincytes and hyperkeratinization produces the characteristic clinical lesions.
