Ten patients (Group 1) with Staphylococcus aureus superinfected atopic dermatitis (SAD) were compared with three control groups without SAD. One control group (Group 2) was comprised of ten atopic patients with total IgE levels of greater than 1000 u/ml, another control group, of six atopic patients (Group 3) with total IgE levels of less than 1000 u/ml and a third group, of ten non-atopics (Group 4), five of whom were infected with Staphylococcus aureus. Total and specific anti-staphylococcal IgE levels and anti-human dander IgE were high in Group 1. Specific IgE levels to S. aureus were slightly increased in some Group 2 patients but were normal (less than 7%) for Group 3. No specific IgE to human dander antigen was detected in either Group 2 or Group 3. In the non-atopic control group (Group 4), six out of ten patients had both low total, and specific IgE antibodies to both staphylococcal, and human dander antigens. Two had increased total IgE and specific anti-staphylococcal IgE antibodies, and two more with a severe, chronic infection, also had anti-staphylococcal IgE antibodies. In SAD patients, a good correlation was seen between cutaneous basophil hypersensitivity and high specific IgE antibodies against staphylococcal and human dander allergens. Delayed type hypersensitivity reactions to staphylococcal antigen were negative or poorly positive in the SAD group by comparison to controls. A paradoxical anaphylactic type of response to the offending bacterial agent in SAD patients, associated with 'auto-atopy' to human dander, is discussed.