10 Signs of Mono, What Causes It and Dangers

Most of us known of infectious mononucleousis by its common names, such as mono or glandular fever. It is also commonly known as kissing disease and is said to be spread by the act of kissing. However, this can be misleading as there are many ways in which mono can be spread even without kissing. It is a very common infection and by the age of 5 years, almost 50% of the American population has been exposed to the virus.

Causes of Mono

Mono is a viral infection. Most of the time it is the Epstein Barr virus (EBV) that is responsible for this infection but sometimes other viruses can also be responsible for this syndrome. Mono is contagious meaning that it is easily spread from one person to another. Once a person gets mono, the immune system produces antibodies against the virus so that a person will not get it again in the future.

Read more on kissing disease.

How do you get mono kissing disease?

The Epstein Barr virus that is mostly responsible for mono is spread through droplets of saliva or other respiratory secretions like mucus. The virus in these infected droplets may enter another person’s mouth or nose and then cause an infection. These droplets may be spread through direct mouth-to-mouth contact like kissing. Hence the term kissing disease.

However, it can also be spread when these infected droplets become airborne during coughing and sneezing. Even sharing eating utensils or consuming the same food and drinks which may be contaminated with an infected person’s saliva can spread mono. People who have mono should therefore bear in mind that these practises can spread the virus and be avoid doing so, at least until the infection resolves.

How To Spot Mono

The term glandular fever is an indication of some of the signs and symptoms of mono, just as the term kissing disease describes one of the ways in which mono is spread.   Enlarged lymph nodes and fever are two of the three typical symptoms, hence the term glandular fever. A sore throat is the other typical symptom of mono.

The symptoms of mono may only appear 1 to 2 months after infection. This is known as the incubation period.  Therefore many people may not recall when, where or from whom they contracted the virus. In children the incubation period may be shorter.

Sore Throat

A sore throat (pharyngitis) is one of the main symptoms of mono. It is often severe and usually mistaken for a bacterial infection (like strep throat). It is not uncommon for a person with mono to initially be prescribed antibiotics. However, since mono is a viral infection it does not respond to antibiotics. The inflammation of the throat usually leads to swollen tonsils and this can persist for several weeks.

Swollen Nodes

Another characteristic feature of mono is swollen lymph nodes (lymphadenopathy). This may feel like little bumps under the skin. It is the neck and armpit lymph nodes that are usually enlarged in mono. This type of lymph node enlargement is due to immune activity which heightens with an infection. Swollen lymph nodes are one of the early symptoms and part of the reason why mono is called glandular fever.


A fever is the other sign that is part of the triad of mono signs and symptoms. It is usuall low-grade meaning that the body temperature is around 38°C (approximately 100°F to 101°F) but under 39°C.  Accompanying symptoms like chills rarely occurs in mono. Along with the other symptoms, the fever may persist for several weeks. It tends to ease first along with the sore throat while the other symptoms may continue for several weeks longer.

Fatigue and Malaise

Two of the first symptoms that arise are fatigue and malaise. Fatigue is extreme tiredness while malaise is a feeling of being unwell. Many people may mistaken this as signs of influenza which never develops fully. Both fatigue and malaise may persist for weeks after the sore throat and fever subsides. However, it can persist for even longer periods if complications of mono arise, such as liver and heart problems.

Read more on malaise.

Other Common Signs and Symptoms

  • Headache
  • Skin rash
  • Nausea
  • Loss of appetite
  • Swollen spleen

Dangers of Mono

Infectious mononucleosis is a common, mild and self-limiting infection in the majority of cases. Complications from mono are rare but can occur in some instances. In extremely rare situations, these complications can be serious and even life-threatening.

  • Very swollen tonsils can obstruct the airway and thereby limit air flow.
  • Hepatitis (liver inflammation) can sometimes occur with mono but is usually mild.
  • Encephalitis (brain) and meningitis (lining of the brain and spinal cord) may occur.
  • Myocarditis which is inflammation of the heart muscle can arise in rare cases.
  • Rupture of the spleen is also rare and can be life-threatening if not treated promptly.
  • Lymphoma is another very rare but possible complication of mono.

Most fo the time when these rare complications of mono do arise, there is some underlying impairment of the immune system. Temporary weakening of the immune system can occur for various reasons in most people. However, it is not these cases where the risky complications of mono arise. Instead people living with HIV and those with AIDS are at a greater risk of rare, serious and even deadly complications of mono. People who had a transplant and are using immune-suppressing medication on a permanent basis are also at risk.

Red Flag Signs

If any of these signs or symptoms arise, emergency medical attention is necessary. It may be due to some of the complications of mono.

  • Difficulty breathing.
  • Confusion.
  • Seizures.
  • Chest pain.
  • Severe abdominal pain.
  • Paleness or even bluish tinge of the skin.
  • Unintentional weight loss.

Although jaundice (yellow discoloration of the skin) due to liver disease is not a serious or immediately life-threatening sign, it nevertheless needs to be investigated further. As mentioned, liver disease that arises as a complication of mono is usually mild. However, the conditions associated with the red flag sign and symptoms are serious and potentially life-threatening.


  1. www.mayoclinic.org/diseases-conditions/mononucleosis/symptoms-causes/dxc-20165844
  2. emedicine.medscape.com/article/222040-followup#e4
  3. www.webmd.com/cancer/news/20031001/kissing-disease-increases-cancer-risk

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