Mono (Mononucleosis) Rash: Causes, Symptoms, & More

By Robynn Lowe
Medically reviewed checkmarkMedically reviewed
April 5, 2022

Mono (Mononucleosis) is a contagious infection usually caused by a herpes virus called Epstein-Barr.

About 45 out of 100,000 people develop infectious mono each year in the United States.

Identifying a mono rash is not that difficult.

That’s because the virus causes a distinctive skin rash.

This article explains how it’s different from other rashes, the treatment options, and how long it takes to heal.

What is a Mono (Mononucleosis) Rash?

A mono rash is a distinctive red, blotchy rash that appears on the chest and back.

It’s one of the most common symptoms of mono. The rash can vary in appearance from one person to another.

The rash is not the only symptom of mono; however, it may be a sign of the infection.

If you have a rash and are concerned it might be a sign of mononucleosis, see your doctor for proper diagnosis.

Is a Mono Rash Contagious?

People who have mono can be contagious from the time they first become infected.

It spreads from person to person through contact with saliva.

It is also termed “the kissing disease” because it can spread through kissing.

It also spreads through coughing and sneezing or when people share something with saliva on it (like a straw, drinking glass, eating utensils, or toothbrush).

Mono can also spread through sexual intercourse and blood transfusions, but this is much less common.

Usually, a person may not know that they have the virus. It takes a while for mono symptoms (like tiredness, fever, muscle aches, headache, or sore throat) to show up.

Some people may carry the virus without ever getting any mono symptoms. So they may not know they have been infected, but they can still pass it to others.

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Common Symptoms 

Below are some common symptoms of mono:

Maculopapular or Morbilliform

A maculopapular or morbilliform rash appears as flat spots on the skin that are pinkish-red.

This type of rash typically starts on the face and behind the ears but can spread down to the neck and chest and eventually across the entire body.

In some cases, it may also present with raised lesions, or abnormal tissues, that are also pinkish red.

Hives

Hives appear as welts on the skin that could be either the same color as the skin or red.

The size of the spots varies. They can be small and round or large and asymmetrical.

The spots are extremely itchy and tend to pop up in one area of the body.

Petechiae

Petechiae are small, brown-purple spots that usually show up on the skin as a result of bleeding.

The spots can be flat or raised.

They often appear on the face, neck, and chest but can also spread to other parts of the body.

Roughly 50% of people with mono will experience this type of rash.

Length of Symptoms

People aged 15–24 years are most likely to develop the classic symptoms of mono.

The incubation period for mono is around six weeks.

During this period, from the time of infection until symptoms appear, a person is contagious.

They appear healthy, but they can spread mono to others.

When symptoms emerge, they may be severe for a few days, then gradually get milder.

Most people feel better after 2–4 weeks, but the fatigue can last for several weeks or months.

Some of the most common symptoms of mono rash are sometimes mistaken for strep throat or the flu.

These include:

  • Fever
  • Sore throat with swollen tonsils that may have white patches
  • Swollen lymph nodes (glands) in the neck
  • Being very tired

Some other symptoms include:

  • Headaches
  • Sore muscles
  • Weakness
  • Belly pain with a larger-than-normal liver or spleen (an organ in the upper left part of the belly)
  • Skin rash
  • Loss of appetite

In rare cases, mono can also cause:

  • Blood problems such as anemia or low platelet counts
  • Inflammation of the heart muscle
  • Inflammation of the brain and spinal cord membranes, known as meningitis
  • Encephalitis, or inflammation of the brain
  • Guillain-Barre syndrome
  • Breathing problems due to swollen tonsils

Common Causes

There are many different types of viruses that can cause a mono-like illness.

The most common cause of mononucleosis is the Epstein-Barr virus (EBV), which is a member of the herpes family of viruses.

The EBV is transmitted through contact with saliva.

Many people who are infected with EBV may never experience symptoms of mono.

In some, the symptoms will be very mild and similar to those of common illnesses, such as a cold or flu.

While EBV is the most common cause of mono, other viruses  can also cause the infection, including:

  • Cytomegalovirus (CMV)
  • Toxoplasmosis
  • HIV
  • Rubella, or German measles
  • Hepatitis A, B, or C
  • Adenovirus

Treatment

While there is no vaccine to prevent mono and no specific medicine to treat the virus, there are ways to ease the symptoms like:

  • Drinking fluids to stay hydrated
  • Resting
  • Taking over-the-counter pain relievers like ibuprofen or acetaminophen for fever, muscle aches, and headache
  • Gargling with warm salt water for a sore throat
  • In more severe cases, a person may need to be hospitalized and given intravenous fluids.

The best way to prevent mono is by avoiding contact with the saliva of an infected person.

This means not sharing drinks, food, cigarettes, or toothbrushes with someone who has mono.

It also means keeping your hands clean and not putting anything in your mouth that has been in contact with infected saliva.

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When to See a Doctor

Most people with mono get better within a few weeks without any medical treatment.

However, you should see a doctor if you have any symptoms that we have mentioned, and they don’t go away within a week or two, especially if you have a fever that lasts for more than three days.

You should also see a doctor if you develop a skin rash, chest pain, shortness of breath, confusion, or seizures. These could be signs of a more serious problem like meningitis or encephalitis.

If you experience any of these problems, seek medical help right away.

How K Health Can Help

Did you know you can get affordable primary care with the K Health app?

Download K to check your symptoms, explore conditions and treatments, and, if needed, text with a doctor in minutes. K Health’s AI-powered app is HIPAA compliant and based on 20 years of clinical data.

Frequently Asked Questions

How do you get a mono rash?
The most common way to get a mono rash is via contact with the saliva of an infected person. This can happen when sharing drinks, food, cigarettes, or toothbrushes with someone who has mono.
Is a mono rash itchy?
There is no one answer to this question since everyone experiences rashes differently. However, in many cases, mono rash symptoms cause itchiness.
The four stages of mono?
There are four stages of mono: 1. The incubation period, which is the time between exposure to the virus and when symptoms first appear. This can be anywhere from four to six weeks. 2. The acute phase is when the symptoms are at their worst. This usually lasts for two to four weeks. 3. The convalescent phase is when the symptoms start to improve. This can last for several weeks or even months. 4. The recovered phase is when the person has fully recovered and no longer has any symptoms of mono.

K Health articles are all written and reviewed by MDs, PhDs, NPs, or PharmDs and are for informational purposes only. This information does not constitute and should not be relied on for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment.

Robynn Lowe

Robynn Lowe is a board certified Family Nurse Practitioner with over 15 years in the medical field. Robynn received her Bachelor's and Master's degrees from Florida Atlantic University and has been practicing in rural family medicine since. Robynn is married to her college sweetheart, Raymond and they have three awesome children. When Robynn isn't with patients you can find her shopping, coaching her kids sports teams, or spending time on the water.