Drug-induced lichenoid reaction
| Lichen planus | |
|---|---|
.JPG) |
|
| Lichen planus affecting the shins | |
| Classification and external resources | |
| Specialty | Dermatology |
| ICD-10 | L43 |
| ICD-9-CM | 697.0 |
| DiseasesDB | 7452 |
| MedlinePlus | 000867 |
| eMedicine | derm/233 derm/663 |
| Patient UK | Lichen planus |
| MeSH | D008010, D017676 |
Lichen planus (LP) is an uncommon disease of the skin with a prevalence of 0.1% in men and 0.3% in women. The cause is unknown, but it is thought to be the result of an autoimmune process with an unknown initial trigger. There is no cure, but many different medications and procedures have been used in efforts to control the symptoms.
The term lichenoid reaction (or lichenoid lesion) refers to a lesion of similar or identical histopathologic and clinical appearance to lichen planus (i.e. an area which looks the same as lichen planus, both to the naked eye and under a microscope). Sometimes dental materials or certain medications can cause a lichenoid reaction. They can also occur in association with graft versus host disease.
Lichen planus (LP) is a chronic inflammatory disease of the skin, mucous membranes and nails.
Lichen planus lesions are so called because of their "lichen-like" appearance and can be classified by the site they involve, or by their morphology.
Lichen planus may be categorized as affecting mucosal or cutaneous surfaces.
Lichen planus lesions can occur in many different forms:
Occasionally, lichen planus is known to occur with other conditions. For example:
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 (Wickham's 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.
Variants of cutaneous lichen planus are distinguished based upon the appearance of the lesions and/or their distribution. Lesions can affect the:
Other variants may include:
Lichen planus affecting mucosal surfaces may have one lesion or be multifocal. Examples of lichen planus affecting mucosal surfaces include:
Oral lichen planus (also termed oral mucosal lichen planus), is a form of mucosal lichen planus, where lichen planus involves the oral mucosa, the lining of the mouth. This may occur in combination with other variants of lichen planus. Six clinical forms of oral lichen planus are recognized:
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