Beschreibung:
<jats:title>Abstract</jats:title><jats:p>A 57‐year‐old man had had deformities of all ten fingernails for one and a half years before presentation and deformities of all ten toenails for the previous six months. The surfaces of the nails were rough, with excessive longitudinal striations. The bases of the nails were slightly hypertrophic, and the tips were atrophic and itchy. A longitudinal nail biopsy including the nail matrix revealed the typical histology of lichen planus. Reticulated pigmentation, maceration, and erosion on the buccal mucous membrane were also discovered. Histological analysis of the buccal mucous membrane revealed lichen planus intermingled with eosinophils. Immunological blood analysis revealed elevated CD4+ T cells and CD4/CD8 ratio. He worked as a tinsmith and had dental metal. The metal series patch test revealed positive reactions to chromate and tin. Treatment with systemic steroids was quite effective in treating the nail lesions.</jats:p>