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Linear lichen planus

Synonym(s) Blaschkoid LP
Blaschkoid lichen planus
Linear LP
Prevalence Unknown
Inheritance -
Age of onset All ages
  • L43.8
  • C0023650
MeSH -
MedDRA -


Disease definition

Linear lichen planus (LLP), also referred to as Blaschkoid LP, is a rare type of lichen planus characterized by a linear distribution of lichenoid lesions along the lines of Blaschko, which are embryonic pathways of skin development.


The prevalence is unknown. Less than 0.5% of patients with LP present with Blaschkoid LP. Cases have been more commonly reported in children, however LLP does occur in adults.

Clinical description

Lesions appear as pruritic, violaceous papules in a linear distribution, usually on the limbs, but also anywhere on the body. It follows a Blaschkoid, not dermatomal, pattern of distribution. It can be superimposed on the more typical non-segmental and randomly-distributed lesions of classic LP. Histology is that of classical papulosquamous lichen planus. A very rare LLP variant, called zosteriform LP, has also been observed and is characterized by a segmental zosteriform distribution of lichenoid lesions. Zosteriform LP may appear as a Koebner phenomenon following herpes zoster infection.


Etiology of LLP is unknown, however it has been associated with metastatic carcinoma, HIV infection and hepatitis C infection. It is thought that LLP arises due to an abnormal keratinocyte clone that is only unmasked after the initiating event for lichen planus.

Expert reviewer(s)

  • Dr Stephanie ARNOLD
  • Dr Susan COOPER

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