1. Infectious Mononucleosis (Mono) Slideshow Pictures
2. Infectious Mononucleosis Medical Pictures Image Collection
3. Take the Quiz - Is it Contagious?

Medical Author:

Melissa Conrad Stöppler, MD

Melissa Conrad Stöppler, MD

Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

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Medical Editor:

William C. Shiel Jr., MD, FACP, FACR

William C. Shiel Jr., MD, FACP, FACR

Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.

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In this Article

• Infectious mononucleosis (mono) facts
• What is infectious mononucleosis?
• What is the cause of mono?
• What are risk factors for mono?
• How is mono transmitted or spread?
• What are the symptoms of mono?
• What are the signs of mono?
• How is mono diagnosed?
• What is the usual course and treatment of mono?
• What are the complications of mono?
• How can mono be prevented?
• Conclusion
• Infectious Mononucleosis (Mono) - Slideshow
• Pictures of Infectious Mononucleosis - Image Collection
• Take the Quiz - Is it Contagious?
• Patient Comments: Infectious Mononucleosis (Mono) - Symptoms
• Patient Comments: Infectious Mononucleosis (Mono) - Treatments
• Infectious Mononucleosis Index

The diagnosis of mono is suspected by the doctor based on the above symptoms and signs. Mono is confirmed by blood tests that may also include tests to exclude other possible causes of the symptoms, such as tests to rule out Strep throat. Early in the course of the mono, blood tests may show an increase in one type of white blood cell (lymphocyte). Some of these increased lymphocytes have an unusual or "atypical" appearance when viewed under a microscope, which suggests mono.

More specific blood tests, such as the monospot and heterophile antibody tests, can confirm the diagnosis of mono. These tests rely on the body's immune system to make measurable antibodies against the EBV. Unfortunately, the antibodies may not become detectable until the second or third weeks of the illness. A blood chemistry test may reveal abnormalities in liver function. Diagnostic tests performed in the laboratory may be of value to rule out other causes of sore throat and fever, including cytomegalovirus infection, Strep throat, and less common conditions such as acute HIV infection or toxoplasmosis.

In most cases of mono, no specific treatment is necessary. The illness is usually self-limited and passes much the way other common viral illnesses resolve. Treatment is directed toward the relief of symptoms. Available antiviral drugs have no significant effect on the overall outcome of mono and may actually prolong the course of the illness. Occasionally, Strep throat occurs in conjunction with mono and is best treated with penicillin or erythromycin (E-Mycin, Eryc, Ery-Tab, PCE, Pediazole, Ilosone). Ampicillin (Omnipen, Polycillin, Principen) and amoxicillin (Amoxil, DisperMox, Trimox) should be avoided if there is a possibility of mono since up to 90% of patients with mono develop a rash when taking these medications. They may then be inappropriately thought to have an allergy to penicillin.

For the most part, supportive or comfort measures are all that is necessary. Acetaminophen (Tylenol) can be given for fever and any headache or body aches. A sufficient amount of sleep and rest is important. The throat soreness is worst during the first five to seven days of illness and then subsides over the next seven to 10 days. The swollen, tender lymph nodes generally subside by the third week.

A feeling of fatigue or tiredness may persist for months following the acute phase of the illness. It is recommended that patients with mono avoid participation in any contact sports for three to four weeks after the onset of symptoms to prevent trauma to the enlarged spleen. The enlarged spleen is susceptible to rupture, which can be life threatening. Cortisone medication is occasionally given for the treatment of severely swollen tonsils or throat tissues which threaten to obstruct breathing.

Patients can continue to have virus particles present in their saliva for as long as 18 months after the initial infection. When symptoms persist for more than six months, the condition is frequently called "chronic" EBV infection. However, laboratory tests generally cannot confirm continued active EBV infection in people with "chronic" EBV infection.