REPORT OF A CASE
A 42-year-old woman presented for examination of a pruritic dermatosis of 3 weeks' duration. The physical examination disclosed a painless, linear, whorled, erythematous, vesicular, and papular eruption on the left side of her trunk, back, and upper arm, from the shoulder downward along the outer aspect of the flexar surface of the arm to the hand (Figure 1). The lesions formed a V over the spine (Figure 2).There was no history of drug ingestion. Family history for similar dermatoses was negative.Two biopsy specimens were obtained from vesicular and papular lesions on the left arm (Figure 3).Antihistamines were administered to control the pruritus. The dermatosis cleared spontaneously in 1 month, leaving a slight hyperpigmentation.What is your diagnosis?
DIAGNOSIS:
Lichen striatus.
HISTOPATHOLOGIC FINDINGS
Histopathologic examination revealed an interface dermatitis with lichenoid and spongiotic features. The epidermis was parakeratotic with focal spongiosis and vacuolar degeneration of the basal layer. A few necrotic keratinocytes were seen. A diffuse, bandlike infiltrate of