Lichen nitidus is believed, by some, to be a variant of lichen planus, and by others to be a distinct entity. We examined five cases of lichen nitidus with immunohistochemical reagents designed to characterize the dermal inflammatory infiltrate in an attempt to resolve the uncertainty. We stained formalin-fixed, paraffin-embedded tissue sections with the following antibodies: L26, A6, KP1, BerH2, OPD4, and HECA-452. The inflammatory infiltrate was 90% A6+, with few L26+ cells. In contrast to lichen planus, KP1+ macrophages were seen and fewer of the lymphocytes demonstrated HECA-452. Fifty percent to 80% of lymphocytes were OPD4 positive, similar to that usually seen in lichen planus. Rare Ki-1+ cells were seen in one case. We believe that the pattern of a mixed cellular infiltrate characterized by macrophages and a helper T cell response with few HECA-452+ cells is somewhat different from the pattern seen in lichen planus, wherein almost all of the cells are CD4+/HECA-452+ lymphocytes. This suggests a different immunologic pathogenesis.