In the cases of infectious eczema that are difficult to diagnose, immunological criteria can be additionally used. The objective of this work was to determine the most significant changes in the immune system in patients with infectious eczema and to develop the additional diagnostic and differential diagnostic criteria for the disease based on these data. Indexes of population and subpopulation spectrum of lymphocytes and content of immunoglobulins and some cytokines were assessed in 100 patients with infectious eczema. These data were compared with the results obtained for 50 patients with true eczema and 30 healthy individuals. It was found that the major manifestations of immune disorders in patients with infectious eczema include an imbalance of immunoregulatory subpopulations (significantly higher level of CD4, CD45RA, and CD4/CD8 ratio and low levels of CD16, CD95, and CD25), humoral immunity (decreased levels of IgM and IgA and increased level of IgG), and cytokine profile (significant increase in the concentration of IL-2). Immunological diagnostic and differential diagnostic criteria of this disease were determined. The use of diagnostic and differential diagnostic immunological criteria of infectious eczema will allow determining the required pathogenetic therapy.