[en] A pruritic vesicular, pustular or squamous eruption confined to the lateral aspect of fingers or toes corresponds to the overall pattern of dysidrosis. Such a clinical pattern is defined by its peculiar topography. It is encountered in diseases resulting from various etiologies. Thus, conceptually, dysidrosis is a common clinical aspect shared by diverse disorders related to different etiologies and pathomechanisms. The dermatopathological assessment and the patch test procedure shed some light on this nosological diversity. Allergic contact dermatitis, irritation dermatitis, mycids, alterations of acrosyringia, and drug or food reactions are eventually involved in this process. However, most cases of dysidrotic dermatoses do not disclose their origins and they remain idiopathic.