What Are the Symptoms of Mononucleosis?

The early symptoms of mononucleosis are like those of the flu, including:

After a day or two, someone with mono may also have:

When to Call the Doctor

Call your doctor about mononucleosis if:

  • You develop severe abdominal pain, which may be a sign of a ruptured spleen. Seek emergency medical treatment immediately.
  • You have the symptoms of mono -- especially for longer than 10 days -- or you have a severe sore throat for more than a day or two. You need to see a doctor to rule out other illnesses, such as strep throat.
  • You develop swollen lymph nodes all over your body, which can also be a sign of some other illnesses.
  • You have severe, persistent headache and a stiff neck, which might be signs of meningitis.
  • You develop a rash consisting of many tiny red spots (which doctors call petechiae), which could be a sign of a low platelet count or other serious illness such as meningitis.
WebMD Medical Reference Reviewed by Nayana Ambardekar, MD on March 30, 2019



American Academy of Family Physicians. 


Mayo Clinic.

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