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Understanding Mononucleosis -- Symptoms

What Are the Symptoms of Mononucleosis?

The early symptoms of mononucleosis resemble those of the flu, including:

  • Severe fatigue
  • Headache
  • Sore throat, which sometimes can be very severe
  • Chills, followed by a fever
  • Muscle aches

After a day or two, these additional symptoms of mono may occur:

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  • Swollen lymph nodes.
  • Jaundice (a yellow tinge to the skin and eyes).
  • A measles-like skin rash anywhere on the face or body; sometimes the rash develops suddenly after taking amoxicillin for a severe sore throat.
  • Tiny red spots or bruise-like areas inside the mouth, especially on the roof of the mouth (palate).
  • Soreness in the upper-left abdomen, from an enlarged spleen.

 

Call Your Doctor About Mononucleosis if:

  • You have been experiencing mono symptoms -- especially for longer than 10 days -- or you have a severe sore throat for more than a day or two. You need to be examined by a doctor to rule out other illnesses, such as strep throat.
  • You develop swollen lymph nodes all over your body, which may be a sign of some other illnesses like cancer or HIV (human immunodeficiency virus).
  • You develop severe abdominal pain, which may indicate a ruptured spleen. Seek emergency medical treatment immediately.
  • You have both a rash and headache, which might be signs of meningitis.
  • You develop a rash consisting of many tiny red spots (called petechiae), which could be a sign of a low platelet count or other serious illness such as meningitis.

WebMD Medical Reference

Reviewed by Daniel Brennan, MD on March 12, 2014

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