- lichen
- A discrete flat papule or an aggregate of papules giving a patterned configuration resembling l. growing on rocks. [G. leichen, l.; a lichenlike eruption]- l. myxedematosus a lichenoid eruption of papules on the upper body of mucinous edema due to deposit of glycosaminoglycans in the skin and fibroblast proliferation, in the absence of endocrine disease. Monoclonal gammopathy is often present. SEE ALSO: scleromyxedema. SYN: papular mucinosis.- l. nitidus minute asymptomatic whitish or pinkish papules; lesions, which are flat-topped, rarely may coexist with l. planus and may involve male genitalia.- l. nuchae l. simplex of the neck, usually in women.- l. obtusus a form in which the papules are large and rounded instead of flattened.- oral (erosive) l. planus oral manifestations of l. planus characterized by white striae (Wickham striae) of the oral mucous membrane and sometimes associated with ulceration; patients may or may not exhibit a history of cutaneous l. planus.- l. planopilaris a rare, patchy alopecia with follicular hyperkeratosis of the scalp and lymphocytic perifolliculitis with l. planus elsewhere.- l. planus eruption of flat-topped, shiny, violaceous papules on flexor surfaces, male genitalia, and buccal mucosa of unknown cause; may form linear groups; microscopically characterized by a band-like subepidermal lymphocytic infiltrate. Spontaneous resolution is common after months to years.- l. planus hypertrophicus verrucoid or warty lesions occurring on legs and thighs in association with l. planus elsewhere. SYN: l. planus verrucosus.- l. planus verrucosus SYN: l. planus hypertrophicus.- l. ruber moniliformis a rare dermatosis consisting of small reddish papules arranged in narrow beaded bands and covering large areas of the body.- l. sclerosus et atrophicus an eruption consisting of pruritic white atrophic papules and plaques that may be discrete or confluent and may contain a central depression or a black keratotic plug microscopically showing epidermal hyperkeratosis and atrophy, superficial dermal edema and homogenization, and mid-dermal inflammation; occurs most commonly in prepubertal and postmenopausal females; vulval involvement was formerly called kraurosis vulvae.- l. scrofulosorum small asymptomatic l. papules on the trunk of children with tuberculosis; acid-fast bacilli are not seen in the dermal granulomas. SYN: papular tuberculid.- l. spinulosus eruption of conical papules, of unknown cause, which have an adherent scaly surface; may be related to l. planus.- l. striatus a self-limited papular eruption occurring primarily in children (more commonly in females); the lesions are arranged in linear groups and usually occur on one extremity.
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li·chen 'lī-kən n2) any of numerous complex plantlike organisms made up of an alga and a fungus growing in symbiotic association on a solid surface (as a rock)* * *
li·chen (liґkən) [Gr. leichēn a tree-moss] 1. any of the many thallophytic plants formed by mutualistic combination of an alga and a fungus, the algal component being a green or blue-green alga, and the fungal usually an ascomycete. 2. any of a number of papular skin diseases in which the lesions are small, firm papules set close together.
Medical dictionary. 2011.
