(BMJ)—A 9-yo girl presented w/ a 15-day hx of abrupt onset of a papular, non-itchy frontofacial rash. She denied any exposures or hx of skin dz. Exam: papular red rash on forehead, nose, and cheek; otherwise, normal. What is the dx?
Facial lichen striatus
Nevus unius lateris
Inflammatory linear verrucous epidermal nevus
Plaque psoriasis
Lichen planus
You are correct. The classic appearance and distribution of the rash along Blaschko lines is consistent w/ facial lichen striatus. It is characterized by linear papules that follow a developmental pattern of skin cell precursors. It commonly affects children 5-15 yo, typically occurring on the extremities and trunk, and less frequently on the face. A confirmative bx is generally not needed for dx because of the classic pattern along Blaschko lines. Lichen striatus is self-limited, but topical steroids or other immunosuppressants may accelerate resolution.

Arch Dis Child 2016;101:1148
By vgreene, 27 March, 2017

EV