Generalized lichenoid drug eruption following Blaschko lines

A 16-year-old girl was referred for evaluation of a widespread rash of 1 month duration. Its onset was on the trunk, but it rapidly generalized to cover virtually the entire body. It was intensely pruritic. The girl had a history of recurrent frontal headaches and had been taking ibuprofen 1 month prior to and during the onset of the rash. She was in otherwise good health. She apeared to be a healthy adolescent with flat topped violaceous papules scattered on her entire body following an arch line unilateral pattern on the right cheek, band-shaped on the neck and ‘‘S’' shaped lines on the frontal chest and abdomen (Fig. 1). They were ‘‘V’' shaped on the back, and had a linear pattern on all limbs. The nails, scalp, oral and genital mucosa were clear. Figure 1. Band-shaped violaceous papules on the neck and arms Download figure to PowerPoint Routine laboratory findings were within normal limits. Serological tests for hepatitis B and C virus infection were negative. Histological features of lichen planus were evident on the skin biopsy specimen: orthokeratosis without parakeratosis, hypergranulosis, liquefactive degeneration of the basal layer, saw-toothing of the rete ridges, pigmentary incontinence in the superficial dermis, band-like interface infiltration of lymphocytes and histiocytes, and colloid bodies within the lower dermis and papillary dermis. There were no eosinophils evident in the dermis. This girl was given cimetidine 400 mg twice daily combined with topical fluticasone proproniate, but after 4 weeks showed no improvement. Methylprednisolone was given 16 mg daily for 2 weeks until remission began, then tapered for another 3 weeks. The pruritus ended after a few days of treatment, whereas the papules slowly resolved leaving behind fading hyperpigmentation, a cosmetic problem. Further treatment involved hydroxyzine and exfoliative ointments, but the hyperpigmentation did not resolve completely (Fig. 2). Figure 2. Hyperpigmented linear macules on the extremities Download figure to PowerPoint