I love how people ask medical questions on NS.
Don't ask us whether you should ski or not, ask a doctor and then decide for yourself.
I did a quick search (took me 5 seconds) and found you some information.
Mononucleosis
What is mononucleosis?
Mononucleosis (often called "mono") is an infection caused by the Epstein-Barr virus. Signs of mono include fever, sore throat, headaches, white patches on the back of your throat, swollen glands in your neck, feeling tired and not feeling hungry.
How is mono passed?
Mono is not spread as easily as some other viruses, such as the common cold. The mono virus is found in saliva and mucus. It is usually passed from one person to another through kissing, although it may rarely be passed in other ways, such as coughing. Signs of mono usually develop 4 to 7 weeks after you're exposed to the virus. Generally, people only get mono once. It's most common among people 15 to 35 years old.
How is mono diagnosed?
Your doctor will probably first ask you some questions about your symptoms and then may do blood tests to confirm the diagnosis. One common test used to diagnose mono is called the Monospot test. Sometimes other blood tests are needed if the results of the Monospot test aren't clear.
Does mono have any complications?
Sometimes. The main serious concern with mono is that the spleen will enlarge and even rupture (tear open). The spleen is like a large gland. It's located in the upper part of your abdomen on the left side. It has functions that relate to your blood.
Although a ruptured spleen is rare in people with mono, it's wise to be aware of the signs and call your doctor right away if you notice any of them. Signs of a ruptured spleen include pain in the left upper part of your abdomen (under the left chest), feeling lightheaded, feeling like your heart is beating fast and hard, bleeding more easily than usual and having trouble breathing.
Can mono be cured?
No. But mono will go away on its own. Symptoms usually last about 4 weeks.
How is mono treated?
The main point of treatment is to relieve your symptoms. The following list includes tips on treatment.
Rest.
Drink plenty of fluids.
If you have a sore throat, gargle with salt water, or suck on throat lozenges, hard candy or flavored frozen desserts (such as Popsicles).
You may want to take acetaminophen (one brand name: Tylenol) or ibuprofen (some brand names: Advil, Motrin, Nuprin) to relieve pain and fever. Do not give aspirin to children. Aspirin should be avoided because it has been associated with a disease called Reye's syndrome in children. Reye's syndrome is a serious illness that can lead to death.
Do I need an antibiotic?
Antibiotics like penicillin are of no help in mono. Mono is caused by a virus, and antibiotics don't work against viruses. If you have a bacterial infection in addition to having mono, your doctor may give you an antibiotic.
What about sports and exercise?
Avoid sports, activities or exercise of any kind until your doctor tells you it's safe. Moving around too much puts you at risk of rupturing your spleen. You need to avoid physical activities for about 3 to 4 weeks after the infection starts.
