History: Where—nail folds, nail matrix, trunk, lower and upper extremities; How long—weeks, months, years? Symptoms—pruritic, painful, bleed?; Quality—red, pink, puffy, tan papules, pink papules?; Severity—good/bad day; Mod. Factors—previous treatment? Context—associations? Timing—when does it occur, is it worse in spring or summer?
Objective:single or clustered pin, skin colored or tan papules; flat-topped, smooth or scaly and are 2mm to 4mm in diameter. Rarely vesicles may be present. Typically there will be a single streak on extremity along Blaschko’s lines; occasionally there is a bilateral distribution &/or multiple parallel bands. It is very uncommon for LS to affect trunk, head or neck region. LS can erupt spreading distally from trunk to an extremity as well as proximal extensions along an extremity.
- LP: will differ in size and color and hypopigmentation from LS. Hyperpigmentation occurs in wake of LP.
- Lichen Nitidus: linear lesions reflect previous traumatic injury to skin
- linear porokeratosis
- linear psoriasis
- linear fixed drug eruption
- Blaschkitis: usually seen in adults, consists of multiple steaks and can have features of dermatitis