11 Silent Signs of Mono You Shouldn’t Ignore

The virus responsible for infectious mononucleosis (commonly known as mono) affects about 90 per cent of the population worldwide, and most commonly strikes teenagers and young adults ages 15 to 30. Knowing what symptoms to look for can help catch the virus—and put you on the path to recovery—sooner.

1 / 11
Woman has sore throat

Sore throat

If you have a sore throat, swollen tonsils, or swollen lymph nodes, especially on the sides of the neck, these could be mono symptoms. Ask your doctor to test for mono in addition to strep throat. “Many people have the Epstein-Barr virus (EBV)—the main viral cause of mononucleosis—in their system throughout their lives, but we can only tell through a blood test,” says Robert I. Danoff, DL, an osteopathic family medicine physician and program director of The Family Medicine Residency and Family Medicine/Emergency Medicine Residency programs at Aria-Jefferson Health in Philadelphia.

These sore throat home remedies may help alleviate symptoms for people with mono or other sore throat causes.

2 / 11
ill allergic rash dermatitis eczema skin of patient

A rash

One of the first signs of mono is if you develop a rash after taking an antibiotic commonly used to treat a sore throat, such as amoxicillin or ampicillin. “These antibiotics are used when a bacterial cause of a sore throat is suspected, prior to the healthcare provider knowing that mono is present. The rash is not an allergic reaction,” says Dr. Danoff.

Got a mysterious rash? Here’s how to tell the difference between six common skin conditions.

3 / 11
A red mark of a lipstick on a glass.

Someone you’ve kissed is sick

Mono is called the “kissing disease” because it’s so easily and frequently spread through saliva (though it can also spread through blood or semen). While you can also pick it up by sharing cups or utensils, an easy clue that you might have more than a common cold is if you and someone you’ve intimately kissed have similar mono symptoms for a prolonged period of time. “It is difficult to prevent spreading mono because once a person has been infected with the EBV virus they can continue to shed it at various times throughout their life,” says Kim Alt, MD, of Rockford Pediatrics in Rockford, Michigan.

Find out 12 simple habits to naturally boost your immune system.

4 / 11
Sleeping woman cover face with blanket flat lay. Close-up of young women, sleeping under white blanket and covering half face.

Severe fatigue

Teens are notorious for being tired all the time, but if they feel severely exhausted for weeks on end (and exhibit other subtle mono symptoms), this could be one of the signs of mono. “Often the person says, ‘Doc, I’m sleeping a lot but I’m still tired and don’t feel like I’m doing too much,'” says Dr. Danoff.

Find out the best supplements to fight chronic fatigue.

5 / 11
Closeup shot of a woman looking at thermometer. Female hands holding a digital thermometer. Girl measures the temperature. Shallow depth of field with focus on thermometer.


If you have a fever (usually more greater than 100.4 degrees Fahrenheit/38 degrees Celsius) or cold that sticks around longer than usual, it could be a sign of mono. “People should suspect mono when they have a prolonged cold-like illness or high fever and swollen glands. They should see their physician, who can confirm with a blood test,” says Adam Horblitt, MD, internal medicine physician at Westchester Medical Center in Valhalla, New York.

Here’s when to worry about a cough that won’t go away.

6 / 11
Young ill woman in bed at home
Africa Studio/Shutterstock

Difficulty breathing

“Complications of mono can cause obstruction of the airway from inflammation, causing difficulty breathing or wheezing,” says Dr. Horblitt. The majority of people who develop symptomatic mono recover within two weeks and develop a strong immunity to EBV, he adds.

Find out how long the common cold normally lasts.

7 / 11
menstruation pain or stomach ache on bed

Abdominal pain

Pain or discomfort on the upper left side of the abdomen could signal an enlarged spleen due to EBV. Avoid rigorous contact sports, which could further damage the spleen, says Dr. Horblitt.

Here are 10 stomach pains you should never ignore.

8 / 11
White empty plate with fork and knife on a old wooden board on a dark wooden background, top view

Decreased appetite

If you don’t feel hungry or can’t bring yourself to eat despite abstaining all day, that could be one of the signs of mono. A healthy diet rich in fruits and veggies and plenty of fluids is key to recovering from the virus.

Check out more health benefits of staying hydrated.

9 / 11
Constrained young mixed race female closing eyes tight and massaging temples with fingers to soothe unbearable migraine. Forgetful girl squeezing head with hands, trying hard to recollect something
WAYHOME studio/Shutterstock


Though less common and easier to attribute to something other than mono, a headache (accompanied by other mono symptoms) can be a sign of mononucleosis.

Find out the three most common types of headaches—and how to cure them.

10 / 11
Woman in a bathrobe is washing hands.
Summer Photographer/Shutterstock

Poor hygiene

“Try not to touch your eyes, nose, or mouth; EBV can live on moist surfaces for hours and if you touch them and then your face, the virus has a pathway to get into your system,” says Dr. Danoff.

Don’t overlook these everyday items that are dirtier than a toilet seat.

11 / 11
health, traditional medicine and ethnoscience concept - ill woman drinking tea with lemon, honey and ginger and paper wipes box on wooden table
Syda Productions/Shutterstock

Developing other illnesses

“Some rare but severe complications of mono include meningitis, encephalitis (inflammation of the brain) and Guillain-Barre (a paralysis disorder),” says Dr. Alt.

Now that you know the mono signs to watch for, check out 50+ more health symptoms you should never ignore.

Reader's Digest
Originally Published on Reader's Digest

Newsletter Unit