Lichenoid drug eruption.

A 78-year-old man presented with an eight-month history of folliculocentric, pink, hyperkeratotic papules and plaques with thick white scale that involved the entire body, with confluence on the buttocks and genitalia. A biopsy specimen demonstrated superficial and focal, mild perivascular and perifollicular, band-like lymphocytic infiltrate and eosinophils. There were lymphocytes extending to the dermo-epidermal junction with vacuolar changes. A diagnosis of lichenoid drug eruption secondary to a proton-pump inhibitor was made. To the best of our knowledge, only one other case of lichenoid drug eruption secondary to a proton-pump inhibitor has been reported.