However, ampicillin and amoxicillin are not recommended during acute Epstein–Barr virus infection as a diffuse rash may develop. Observation
Splenomegaly is a common symptom of infectious mononucleosis and health care providers may consider using abdominal ultrasonography to get insight into the enlargement of a persons spleen. However, because spleen size varies greatly, ultrasonography is not a valid technique for assessing spleen enlargement and should not be used in typical circumstances or to make routine decisions about fitness for playing sports. Prognosis
Serious complications are uncommon, occurring in less than 5% of cases:
CNS complications include meningitis, encephalitis, hemiplegia, Guillain–Barré syndrome, and transverse myelitis. Prior infectious mononucleosis has been linked to the development of multiple sclerosis. Hematologic: Hemolytic anemia (direct Coombs test is positive) and various cytopenias, and bleeding (caused by thrombocytopenia) can occur. Mild jaundice
Hepatitis with the Epstein–Barr virus is rare. Upper airway obstruction from tonsillar hypertrophy is rare. Fulminant disease course of immunocompromised people are rare. Splenic rupture is rare. Myocarditis and pericarditis are rare. Postural orthostatic tachycardia syndrome
Chronic fatigue syndrome
Cancers associated with the Epstein-Barr virus include Burkitts lymphoma, Hodgkins lymphoma and lymphomas in general as well as nasopharyngeal and gastric carcinoma. Hemophagocytic lymphohistiocytosisOnce the acute symptoms of an initial infection disappear, they often do not return. But once infected, the person carries the virus for the rest of their life. The virus typically lives dormant in B lymphocytes. Independent infections of mononucleosis may be contracted multiple times, regardless of whether the person is already carrying the virus dormant.
The host immune response involves cytotoxic (CD8-positive) T cells against infected B lymphocytes, resulting in enlarged, atypical lymphocytes (Downey cells).When the infection is acute (recent onset, instead of chronic), heterophile antibodies are produced.Cytomegalovirus, adenovirus and Toxoplasma gondii (toxoplasmosis) infections can cause symptoms similar to infectious mononucleosis, but a heterophile antibody test will test negative and differentiate those infections from infectious mononucleosis.Mononucleosis is sometimes accompanied by secondary cold agglutinin disease, an autoimmune disease in which abnormal circulating antibodies directed against red blood cells can lead to a form of autoimmune hemolytic anemia. The cold agglutinin detected is of anti-i specificity. Diagnosis
Diagnostic modalities for infectious mononucleosis include:

Persons age, with highest risk at 10 to 30 years. Medical history, such as close contact with other people with infectious mononucleosis, and the presence and time of onset of "mononucleosis-like symptoms" such as fever and sore throat. Physical examination, including palpation of any enlarged lymph nodes in the neck, or enlarged spleen. The heterophile antibody test is a screening test that gives results within a day, but has significantly less than full sensitivity (70–92%) in the first two weeks after clinical symptoms begin. Serological tests take longer time than the heterophile antibody test, but are more accurate. Physical examination
The presence of an enlarged spleen, and swollen posterior cervical, axillary, and inguinal lymph nodes are the most useful to suspect a diagnosis of infectious mononucleosis.