Linear rash from shoulder to wrist
This patient’s rash wasn’t pruritic, painful, or tender, but it formed a unique pattern.
Distinguishing lichen striatus from other linear skin disorders
Other lesions that could follow Blaschko’s lines include linear psoriasis, linear lichen planus, inflammatory linear verrucous epidermal nevus, and linear Darier’s disease (keratosis follicularis).3
Linear psoriasis usually presents as late-onset, mildly pruritic linear scaly plaques with a positive Auspitz sign. This form of psoriasis responds well to topical or systemic psoriatic treatment, such as topical steroids, coal tar preparation, or vitamin D derivatives.4
Linear lichen planus involves pruritic, hyperpigmented, well-demarcated, flat-topped papules and small, thin plaques without scale. Linear lichen planus can be the result of scratching or injuring the skin.5
Inflammatory linear verrucous epidermal nevus usually presents as erythematous and verrucous papules with a psoriasiform appearance. It is accompanied by intense pruritus. Girls are more commonly affected than boys and the condition is refractory to psoriatic therapy.6
Darier’s disease (keratosis follicularis) is an autosomal dominant inherited disease that usually presents as an eruption of keratotic papules. Nails may be affected, with longitudinal nail striations and subungual hyperkeratosis.7
