SUMMARYExperimental scratching induced phloxinophilic eosinophilic bodies in unaffected skin of ten patients with active lichen planus. This reaction was inhibited by concomitant local injection of methylprednisolone acetate and could not be induced in patients with inactive lichen planus, in patients with other dermatoses, nor in healthy subjects. The findings are consistent with a viral aetiology for lichen planus.