Recent information implicates the stimulation of T cells byStaphylococcus aureusantigens and exotoxins as a likely factor in provoking the inflammatory response in atopic dermatitis.S. aureussecrets exotoxins called superantigens, which stimulate a large proportion of T cells. In addition, protein A, a component of the cell wall ofS. aureus, is a potent B cell mitogen. This understanding provides a rationale for attempting to reduce the staphylococcal skin colonization of patients with severe atopic dermatitis and correlates with the clinical observation in a number of situations of marked improvement in atopic dermatitis following antibiotic treatment.