The Serum Levels of IL-4, IL-5 and IFN-γ in Skin Allergy- and Measles- Induced Exanthema

Macular or maculopapular skin reactions are frequent events in skin allergies as well as in viral infections. Clinically, the differentiation may be difficult in the absence of a clear relationship with drug intake or in the failure to detect measles virus-specific antibodies. Studies on drug-specific T cell lines and T cell clones isolated from skin-allergy patients have suggested that these cells may represent a significant source of IL-4 and IL-5. On the other hand, viral infections are frequently associated with elevated IFN-γ levels. Determination of serum cytokine levels helps to differentiate between skin allergies and virally induced skin eruptions. Forty patients suffering from skin allergy and 40 patients with measles infection entered the study. Serum IL-4, IL-5 and IFN-γ levels were determined by ELISA assay for skin-allergy and measles patients. In 37/40 patients with skin allergy, IL-4 was elevated and in 6/40 patients with skin allergy IFN-γ was measurable. In 29/40 patients with measles infection, IFN-γ serum levels were elevated and 32/40 patients with measles had elevated IL-4 levels. IL-5 was increased in 32/40 patients with measles infection and in 34/40 patients with skin allergy. These data underline the distinct pathogenesis of these morphologically similar exanthemas and suggest that a combined analysis of IL-4, IL-5, and IFN-γ might help differentiate skin eruptions.