Lichen Striatus Flashcards
what are the lines of blaschko?
Lines of normal cell development in the skin, invisible under normal conditions, apparent with skin/mucosal diseases
what is Lichen striatus?
Lichen striatus (LS) is an uncommon, benign, self limited papular eruption that follows the lines of blaschko
Epidemiology
MC in young children, favors females
Morphological patterns of LS?
3.
Typical LS (most common)
LS albus
Nail LS (least common)
Nail LS
Almost exclusively in children, usually restricted to a single nail
LS albus
Hypopigmented lesions
Typical LS clinical manifestations
Crops of tiny 1-2 mm scaly erythematous or flesh colored flat topped papules that appear abruptly w/o any known trigger. Lesions solitary and unilateral usually
MC seen in the limbs
Pt usually asymptomatic, minority can develop pruritus
Typical LS natural course
Develops over a few weeks
Self resolves in 6-24 months
Only LT sequela: postinflammatory hypopigmentation (dark complexioned individuals)
Etiology
Unknown
Seems to be product of a combination of genetic and environmental factors
Genetic mosaicism provides the underlying substrate for LS
85% pts have personal or family Hx Atopy
Suggested pathogenesis
Somatic mutation making certain Keratinocyte lineages susceptible to an unidentified environmental trigger/insult, basal Keratinocytes present antigens from this trigger to CD8+ T cells –> autoimmunity
Differential Dx
Linear lichen planus, lichenoid nitidus, lichenoid spinulosis, Gianotti-Crosti Syndrome, chronic GVHD and frictional lichenoid eruption
What favors Dx LS?
(-): pruritus, koebnerization, oral lesions, systemic manifestations
(+): postinflammatory hypopigmentation, nail dystrophy
How do you Dx LS?
Clinical one, biopsy usually not necessary since LS is self limited and histopathology is non specific sharing features of eczema and lichen planus
When a biopsy would be necessary?
Lesions > 1 y to distinguish from inflammatory linear epidermal nevi, which is associated with organ involvement and a slight risk of malignant transformation
Classic biopsy finding?
perivascular inflammatory infiltrate, both superficial and deep
LS management
Since it is self limited, Tx usually not needed, just observe and reassure
If Tx desired (pruritus/cosmesis): OK to use topical CS
