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Educational use only: Symptom.Today is an educational tool and does not provide medical advice, diagnosis, or treatment. Results are not a substitute for professional medical care. If symptoms are severe, worsening, or concerning, seek medical attention immediately. In an emergency, call your local emergency number.
Infectious DiseaseModerate

Infectious Mononucleosis

Infectious mononucleosis, often called mono or the kissing disease, is a viral infection that causes fatigue, fever, and a sore throat. It is most common among teenagers and young adults and typically resolves with rest and hydration.

Severity
Moderate
System
Whole body
Progression
Gradual
Treatable
Yes — usually with self-care or routine treatment
Common age
All ages
Duration
Acute (days–weeks)
Contagious
Yes
Emergency risk
High
Whole body
Affected area: Whole body

Overview

Infectious mononucleosis, often called mono or the kissing disease, is a viral infection that causes fatigue, fever, and a sore throat. It is most common among teenagers and young adults and typically resolves with rest and hydration.

Symptoms

Click any symptom to analyze
Primary symptoms

No symptoms mapped yet.

Causes

  • Epstein-Barr virus (EBV)
  • Saliva contact (sharing drinks, kissing)
  • Blood or semen contact (rarely)

Risk factors

  • Being between the ages of 15 and 24
  • Being a student or living in dormitories
  • Working in healthcare or childcare settings
  • Weakened immune system

How it progresses

3 stages
  1. Onset
    Symptoms appear, often triggered by a known cause.
    Often missed
  2. Active phase
    Symptoms peak; self-care or short treatment usually helps.
  3. Resolution
    Symptoms ease over days to weeks with proper care.

How it's diagnosed

  • Physical examination of lymph nodes and spleen
  • Monospot blood test
  • Complete blood count (CBC) to check for abnormal white cells

Treatment options

General educational information only — no dosage advice. Always follow guidance from a qualified clinician.

Medical
  • Pain and fever management medications
  • Treatment of secondary infections if they occur
Home care
  • Drinking plenty of fluids to stay hydrated
  • Taking over-the-counter pain relievers (acetaminophen or ibuprofen)
  • Gargling with saltwater for throat pain
  • Resting and avoiding physical activity
  • Rest and limiting physical activity
  • Hydration and fluid management

Complications

  • Reduced quality of life
  • Worsening symptoms over time
  • Recurrence of infectious mononucleosis

Prevention

  • Wash hands frequently
  • Avoid close contact with infected people
  • Stay up to date with vaccines
  • Maintain a healthy lifestyle
  • See a clinician for routine check-ups

When to seek help

Urgent — same-day care
  • Symptoms persist beyond a few days
  • Symptoms interfere with daily activities
  • New or worsening symptoms appear
  • Concerning changes related to infectious mononucleosis
🚨 Emergency — call now
  • Sudden, sharp pain in the left upper abdomen
  • Difficulty breathing or swallowing
  • Extreme weakness or dizziness
  • Yellowing of the skin or eyes (jaundice)

In any emergency, call your local emergency number or go to the nearest emergency department.

Real-world questions

  • Can Infectious Mononucleosis cause headaches?
  • Is Infectious Mononucleosis reversible?
  • How quickly does Infectious Mononucleosis progress?
  • Is Infectious Mononucleosis hereditary?
  • Can Infectious Mononucleosis be prevented?

Frequently asked questions

What causes Infectious Mononucleosis?

Possible causes of Infectious Mononucleosis include Epstein-Barr virus (EBV), Saliva contact (sharing drinks, kissing), Blood or semen contact (rarely).

Is Infectious Mononucleosis dangerous?

Infectious Mononucleosis is generally moderate, but severity can vary. Seek care if symptoms are severe or persistent.

How long does Infectious Mononucleosis last?

Duration varies between individuals. Many cases improve with appropriate care, while others may persist longer and require ongoing management.

Can Infectious Mononucleosis go away on its own?

Some milder cases may improve with rest and self-care. If symptoms persist or worsen, consult a healthcare professional.

When should I see a doctor about Infectious Mononucleosis?

Consider seeing a clinician if symptoms are severe, persistent, worsening, or if you have any concerns related to general.

Sources

Information based on general medical references such as:

CDCNHSWHOMedlinePlus

Last reviewed: May 2026

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Educational use only: Symptom.Today is an educational tool and does not provide medical advice, diagnosis, or treatment. Results are not a substitute for professional medical care. If symptoms are severe, worsening, or concerning, seek medical attention immediately. In an emergency, call your local emergency number.