In contrast to conventional antigens, bacterial superantigens activate a large percentage of an organism's total T-cell repertoire. This has clinical implications particularly in the case of infections with Gram-positive bacteria. Unravelling the molecular mechanisms of superantigen-mediated T-cell activation has yielded new insights in the pathogenesis of a number of diseases, in the field of dermatology namely atopic dermatitis and psoriasis. Moreover, therapeutic applications of superantigens have begun to emerge.