DEAR DOCTOR K: What is mononucleosis, and why is it called the “kissing disease”?
DEAR READER: Mononucleosis, or “mono,” is an illness caused by several viruses, primarily the Epstein-Barr virus (EBV). Mono was nicknamed the “kissing disease” because EBV commonly is transmitted during kissing. The virus lives in different parts of the body, including the throat. The virus can leave throat cells and enter the saliva.
Most viruses that infect us enter our body, maybe cause temporary illness, and then get killed by the immune system. EBV is different. It is a member of the herpesvirus family, a cousin to the virus that causes cold sores and genital sores. Once any member of the herpesvirus family infects you, it remains in your body for the rest of your life. The immune system can suppress it, but cannot eliminate it.
In the United States, most people get infected with EBV when they are teenagers or young adults. When a person is first infected with EBV, the virus does not always cause mononucleosis. Sometimes EBV causes only a mild illness or no illness at all. When EBV does cause mono, the first symptoms typically include fever, headaches, muscle aches and unusual fatigue. The fatigue may be overwhelming, compelling a person to sleep for 12 to 16 hours at a stretch.
These symptoms are quickly followed by sore throat, enlarged lymph nodes, joint aches, loss of appetite, a red rash (usually on the chest), abdominal pain and an enlarged spleen.
The spleen is a small organ near the stomach. In rare cases, an enlarged spleen can rupture, causing life-threatening internal bleeding. It is important to protect the spleen from rupture. A person who develops mono should avoid strenuous activities, especially contact sports, for at least four weeks. They should wait even longer if their doctor finds their spleen is still enlarged.
Symptoms usually are most intense during the first two to four weeks of the illness. But some symptoms, especially fatigue, can last for several months or longer. A study published in 2006, organized by the U.S. Centers for Disease Control and Prevention (CDC), found that 11 percent of people with new EBV infections leading to mono developed chronic fatigue syndrome and remained ill a year or more after the initial infection.
There is no medical cure for mononucleosis. Most treatment focuses on making the person more comfortable. Recovery usually calls for getting plenty of rest and fluids and treating symptoms. Cold drinks, frozen desserts and gargling with salt water can help to relieve minor sore throat pain. Ibuprofen (Advil, Motrin) or acetaminophen (Tylenol) can help fight fever and body aches. Prednisone can shrink extremely swollen tonsils.
This disease is most contagious during its acute stage, when the affected person still has a fever. The patient does not need to be kept isolated from others, but he or she should avoid kissing others while feeling ill. Also avoid sharing food, drinks or eating utensils during the first few weeks of the illness.
So the “kissing disease” is real. But kissing is rarely a danger to your health.
Dr. Komaroff is a physician and professor at Harvard Medical School. To send questions, go to AskDoctorK.com, or write: Ask Doctor K, 10 Shattuck St., Second Floor, Boston, MA 02115.