Conditions
Mononucleosis: symptoms, testing and a video doctor visit
Mononucleosis (mono, or "the kissing disease") is an infection usually caused by the Epstein-Barr virus, common in teens and college students. It causes extreme tiredness, fever, a sore throat and swollen glands, and most people get better in 2 to 4 weeks. Antibiotics do not cure it. We see you by video in Puerto Rico and, if needed, give you a lab order.
Is it an emergency? Call 911.
Is this an emergency?
This is not an emergency service. Call 911 or go to the nearest emergency room if you have:
- Sudden, sharp, severe belly pain, especially upper left
- Trouble swallowing or breathing, or a child who drools and cannot swallow
- A stiff neck or severe weakness
- Yellow skin or eyes
- A baby under 3 months with a temperature of 100.4 °F (38 °C) or higher
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At a glance
Infectious mononucleosis
Common symptoms
- Extreme tiredness
- Fever
- A sore throat that gets worse, with swollen tonsils covered in a white or yellow coating
- Swollen glands in the neck and armpits
- Headache and body aches
- Loss of appetite
- A rash, especially after taking amoxicillin or ampicillin
- Other names
- Mono · Kissing disease · Glandular fever · Epstein-Barr virus infection
- Usual test
- Monospot or EBV antibody test and a blood count, when needed
- Treatment
- Rest, fluids and medicine for fever and pain
- Possible complication
- Ruptured spleen (rare)
On this page(9)
What is mononucleosis?
Infectious mononucleosis is almost always caused by the Epstein-Barr virus (EBV); rarely, by other viruses. It spreads mostly through saliva: kissing or sharing cups, utensils or toothbrushes. It can also spread through blood and semen. That is why it is called "the kissing disease".
It is common in teens and young adults, especially college students: according to the CDC, at least 1 in 4 teens and young adults infected with EBV develops mononucleosis. It can happen at any age.
How we care for mono by video
You see Dr. Diana Nieves Castro, a Puerto Rico–licensed general practice physician with several years of emergency-department experience, in English or Spanish. We evaluate, diagnose and treat: the doctor asks how long you have been sick, what your sore throat is like, whether you have fever, swollen glands or pain in the upper left side of your belly, and asks you to show her your throat and neck on camera.
The diagnosis is often made from symptoms. If it needs confirming, we give you a lab order for a lab near you: a monospot or EBV antibody test and a complete blood count (CBC). If your sore throat could be strep, read about sore throat. If appropriate, the doctor prescribes and we send your prescription to your pharmacy.
If you need a doctor’s note for school, college or work, it is included after your visit.
Your doctor
Dr. Diana Nieves Castro, MD
General practice physician
Several years of emergency-department experience.
Founding Executive Director of The Health Initiative.
Your visit in 3 steps
Request a visit online 24/7 — we confirm your time by email or text See how our online doctor visit works.
Request your visit.
Book a visit and choose "Doctor visit". You pay by card when you request it.
See the doctor by video.
We send you a secure video link. It works on your phone, tablet or computer.
Get your plan.
Home care, a lab order if needed, your doctor’s note and when to return to sports.
What the visit costs
A doctor visit costs US$79, the same price for every age, with no membership. You pay by card when you request the visit, and you get a full refund if the visit can’t take place. A doctor’s note is included. We do not bill insurance; the lab and the pharmacy charge separately. See all prices. The service is run by The Health Initiative, a nonprofit.
Mono symptoms
Symptoms usually start slowly:
- Extreme tiredness
- Fever
- A sore throat that gets worse, with swollen tonsils covered in a white or yellow coating
- Swollen glands in the neck and armpits
- Headache and body aches
- Loss of appetite
- A rash, especially after taking amoxicillin or ampicillin
Mononucleosis treatment and protecting your spleen
No medicine cures it: treatment eases symptoms while your body clears the virus. Rest, drink plenty of fluids, gargle with warm salt water for your throat, and use acetaminophen or ibuprofen for fever and pain, as the label directs. Antivirals have little or no benefit. If symptoms are severe, the doctor may consider other medicines.
Antibiotics and rash: antibiotics do not work against a virus. The CDC says that if you have mono, you should not take penicillin-type antibiotics such as ampicillin or amoxicillin; with them, a pink, measles-like rash is more likely. If you got one after taking them, tell the doctor. Read more about antibiotics.
Your spleen and sports: mono can enlarge the spleen, and a blow can rupture it. The CDC advises avoiding contact sports until you fully recover; according to MedlinePlus, swollen glands and the spleen usually heal in about 4 weeks. Do not go back to basketball, football, baseball or weightlifting until the doctor clears you.
How long it lasts: the fever usually drops in about 10 days and most people feel better in 2 to 4 weeks, but tiredness can last 2 to 3 months. You can spread it while you have symptoms and for up to a few months afterwards: avoid kissing and sharing cups or utensils.
If your glands stay swollen after you recover, read about swollen lymph nodes.
Mono in children and teens
The doctor sees children and teens of all ages by video; patients under 21 need a parent or legal guardian on camera for the whole visit, with ID. Never give aspirin to a child or teen.
For their safety, go to the emergency room or call [911](tel:911) if your child, at any age, has trouble breathing, drools or cannot swallow, has sudden severe belly pain (especially upper left), a stiff neck with a bad headache, or is very drowsy and hard to wake. A baby under 3 months with a temperature of 100.4 °F (38 °C) or higher also needs the ER.
When to go to the ER
For your safety, call 911 or go to the emergency room if you have any of these signs. See when to go to the ER.
- Sudden, sharp, severe belly pain, especially upper left (possible ruptured spleen)
- Trouble swallowing or breathing
- A stiff neck or severe weakness
- Yellow skin or eyes
How we care for you
We evaluate, diagnose and treat; if needed, we give you a lab order for a lab near you.
We see adults and children of all ages. Patients under 21: a parent with patria potestad (parental authority) or a legal guardian is on camera for the whole visit and shows photo ID.
Real-time video visit. We send you a secure video link. It works on your phone, tablet or computer.
If appropriate, the doctor prescribes and we send your prescription to your pharmacy. We do not prescribe controlled substances.
You must be physically in Puerto Rico during the visit (visitors, tourists and cruise passengers are welcome).
In an emergency, call 911.
Frequently asked questions
How long does mono last?
Why did I get a rash from amoxicillin?
When can I play sports again after mono?
Is mono contagious?
About this page
Author: The Health Initiative
Medical care provided by Dr. Diana Nieves Castro, MD (PR license 24027)
Disclosure: Founding Executive Director of The Health Initiative
Published: 2026-10-02 · Updated: 2026-10-02
Sources (3)
- Mononucleosis (MedlinePlus, NIH) (opens in a new tab) (accessed 2026-10-02)
- About Infectious Mononucleosis (CDC) (opens in a new tab) (accessed 2026-10-02)
- Fever in under 5s, NG143 (NICE) (opens in a new tab) (accessed 2026-10-02)