Researchers also think that an imbalance in the immune system may contribute to the development of atopic dermatitis. It appears that the part of the immune system responsible for stimulating IgE is overactive, and the part that handles skin viral and fungal infections is underactive. Indeed, the skin of people with atopic dermatitis shows increased susceptibility to skin infections. This imbalance appears to result in the skin's inability to prevent inflammation, even in areas of skin that appear normal. In one project, scientists are studying the role of the infectious bacterium Staphylococcus aureus (S. aureus) in atopic dermatitis.

Researchers also think that an imbalance in the immune system may contribute to the development of atopic dermatitis.

Researchers believe that one type of immune cell in the skin, called a Langerhans cell, may be involved in atopic dermatitis. Langerhans cells pick up viruses, bacteria, allergens, and other foreign substances that invade the body and deliver them to other cells in the immune defense system. Langerhans cells appear to be hyper-active in the skin of people with atopic diseases. Certain Langerhans cells are particularly potent at activating white blood cells called T cells in atopic skin, which produce proteins that promote allergic response. This function results in an exaggerated response of the skin to tiny amounts of allergens.

Scientists have also developed mouse models to study step-by-step changes in the immune system in atopic dermatitis, which may eventually lead to a treatment that effectively targets the immune system.