Distinct serum cytokine levels in drug- and measles-induced exanthema

Background: Macular or maculopapular skin reactions are frequent events in drug allergy as well as in viral infections. Clinically, the differentiatio n may be difficult in the absence of a clear relationship to drug intake or failure to detect virus-specific antibodies of the IgM class. Studies on d rug-specific T cell lines and T cell clones isolated from drug-allergic pat ients have suggested that these cells may represent a significant source of IL-5. On the other hand, viral infections are frequently associated with e levated IFN-gamma levels. Objective: Determination of serum-cytokine levels to differentiate between drug- and virally induced skin eruptions. Patient s: 18 patients suffering from acute drug allergy and 19 patients with acute measles, rubella or parvovirus infection, Measurements: Cytokine-ELISA (IL -5, IL-4 and IFN-gamma) of sera collected during acute drug allergy or duri ng acute measles, rubella or parvovirus infection. Results: In 12/18 patien ts with drug allergy, IL-5 and/or IL-4 were elevated. A significant correla tion (r(Spearman) = 0.84) between IL-5 serum levels and eosinophil counts i n the blood was found. No correlation was detected between IL-4 and blood e osinophilia or between IL-4 and IL-5 levels. After remission, IL-5 and IL-4 decreased to undetectable levels. IFN-gamma on the other hand was not meas urable in patients with drug allergy while elevated IFN-gamma serum levels were detected in 17/19 patients with measles, rubella or parvovirus infecti on; 2 patients with acute virus infection had elevated IL-5, and/or IL-4 an d IFN-gamma levels. Conclusion: These data underline the distinct pathogene sis of these morphologically similar exanthemas and suggest that the combin ed analysis of eosinophilia in the blood, IL-4 and IFN-gamma might help in differentiating skin eruptions. Copyright (C) 1999 S. Karger AG. Basel.