Although nail abnormalities have been reported to occur in 1% to 10% of patients with lichen planus, in children with lichen planus they are rarely mentioned in the literature. An 11-year-old boy had a two-month history of nail dystrophy affecting all the fingernails and the great toenails. The nail plates showed longitudinal ridging and thinning as well as onycholysis and distal splitting. There were no cutaneous or mucous membrane abnormalities. A nail biopsy specimen showed hyperkeratosis, hypergranulosis, and acanthosis in the ventral portion of the proximal nail fold and in the nail matrix. A band-like lymphocytic infiltrate was present in the superficial dermis, and the basal layer showed vacuolar alterations. A diagnosis of lichen planus was made. Treatment was intramuscular triamcinolone 20 mg once a month for six months. Since 1969 only 13 proved pediatric cases of lichen planus limited to the nails have been reported, including two children with 20-nail dystrophy and four with idiopathic atrophy of the nails.