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The absolute eosinophil count is only slightly elevated, but the lymphocyte count is more significantly elevated, referred to as lymphocytosis. The vast majority of the time, lymphocytosis is caused by an infection. The most common cause of this would be an acute viral infection. There are also a few possible bacterial or protozoal infection that can cause lymphocytosis. Some chronic infections can also cause a lymphocytosis, such as tuberculosis. Leukemia can cause a chronic elevation of the lymphocytes, but is less likely than an infection. An increased number of eosinophils, referred to as eosinophilia, is frequently caused by allergies, but can also be due to parasitic infections, inflammatory diseases, or lymphoma. Many doctors will only pursue further evaluation if there is persistent elevation of the white cells, which will allow for the spontaneous resolution of many of the common causes.