A strep infection is caused by a family of bacteria called Streptococcus. These round-shaped bacteria can cause a range of illnesses — from a mild sore throat to more serious conditions. Understanding what strep bacteria are, how they spread, and how they are treated can help you protect yourself and your family.
What Is a Strep Infection?
Streptococcus bacteria are tiny, round germs that cluster together in chain-like formations. Scientists classify them into more than 20 different groups, labelled A, B, C, and so on. Each group behaves differently in the body.
Group A Streptococcus is the most common cause of strep infection in humans. It carries a special outer coating and a surface protein called M protein. These features make it particularly good at avoiding your immune system.
Groups B and D are also important, though they tend to cause less severe illness in most healthy people. However, Group B strep can be very dangerous for newborns and pregnant women. Your family doctor can help you understand your personal risk.
Types of Strep Infection You Should Know
Not all strep infections look the same. The type of illness you get depends on which group of bacteria is involved and where in your body the infection takes hold.
Group A Strep Infections
Group A strep is responsible for the most well-known illnesses. These include strep throat, scarlet fever, and skin infections like impetigo. In rare cases, it can lead to more serious conditions such as rheumatic fever or toxic shock syndrome.
Strep throat is especially common in school-age children. It spreads easily through coughing, sneezing, and close contact. Canadian public health authorities recommend prompt treatment to prevent complications.
Group B Strep Infections
Group B strep most often affects pregnant women, newborns, and older adults. In Canada, routine screening for Group B strep is offered to pregnant women between 35 and 37 weeks. This simple swab test can prevent life-threatening infection in newborns.
If you are pregnant, your provincial health plan typically covers this screening. Ask your midwife or obstetrician at your next prenatal appointment.
Group D and Other Strep Groups
Group D strep, which includes bacteria like Enterococcus, can cause urinary tract infections and infections of the heart valves. These are less common in healthy adults. However, they can be serious in people with weakened immune systems or existing heart conditions.
How Does a Strep Infection Spread?
Strep bacteria spread mainly through respiratory droplets. When an infected person coughs or sneezes, tiny droplets carry the bacteria into the air. You can breathe them in or pick them up by touching a contaminated surface and then touching your face.
Crowded places like schools, daycares, and public transit are common settings for strep to spread in Canada — especially during the fall and winter months. Good hand hygiene remains your best defence.
In addition, sharing utensils, cups, or food with an infected person raises your risk. Children are especially vulnerable because they are in close contact with others throughout the school day. Teaching kids to wash their hands regularly is one of the most effective prevention strategies.
Recognising the Symptoms of a Strep Infection
Symptoms of a strep infection vary depending on the type and location of the infection. Knowing what to look for can help you act quickly and get the right care.
Strep Throat Symptoms
The most common signs of strep throat include a sudden, severe sore throat and pain when swallowing. You may also notice swollen lymph nodes in your neck and white patches on your tonsils. A fever above 38°C (100.4°F) is also very common.
Unlike a cold or flu, strep throat usually does not cause a runny nose or cough. If your sore throat comes on suddenly without cold-like symptoms, it is worth getting tested. A rapid strep test at your walk-in clinic can give results in minutes. For more detail, visit the Mayo Clinic’s guide to strep throat symptoms.
Skin and Other Symptoms
Strep bacteria can also cause skin infections like impetigo, which appears as red sores or blisters around the nose and mouth. Scarlet fever produces a rough, sandpaper-like rash that usually starts on the chest and spreads. Both conditions require antibiotic treatment.
In more serious cases, a strep infection can spread to the bloodstream. This is called invasive Group A strep disease. Symptoms include high fever, severe muscle pain, and rapidly worsening illness. This is a medical emergency — call 911 or go to your nearest emergency room immediately.
How Is a Strep Infection Diagnosed and Treated?
Diagnosing a strep infection usually starts with a physical exam. Your doctor or nurse practitioner will look at your throat and feel for swollen lymph nodes. They may then perform a rapid strep test using a simple throat swab.
Results from a rapid test are usually available within 10 to 15 minutes. If the rapid test is negative but your doctor still suspects strep, they may send a throat culture to a lab for a more thorough analysis. Results from a culture take 24 to 48 hours.
Antibiotic Treatment
The standard treatment for a strep infection is a course of antibiotics — most commonly amoxicillin or penicillin. It is very important to finish the full course, even if you start feeling better after a few days. Stopping early can allow the bacteria to survive and develop resistance.
Most people feel significantly better within 24 to 48 hours of starting antibiotics. In Canada, antibiotics for strep are available by prescription only. Your provincial health plan may cover the cost, depending on your province and coverage level.
Managing Symptoms at Home
While antibiotics fight the infection, you can manage discomfort at home. Over-the-counter pain relievers like acetaminophen (Tylenol) or ibuprofen can reduce fever and ease throat pain. Drinking warm liquids, using a humidifier, and getting plenty of rest also help your body recover.
Furthermore, staying home from school or work for at least 24 hours after starting antibiotics helps prevent spreading the infection to others. This is especially important in households with young children or elderly family members.
Preventing a Strep Infection
Prevention is always better than treatment. Fortunately, there are straightforward steps you can take to reduce your risk of a strep infection.
Wash your hands often with soap and water for at least 20 seconds, especially after coughing or sneezing.
Avoid sharing cups, utensils, or personal items with someone who is sick.
Cover your mouth and nose when you cough or sneeze, using a tissue or your elbow.
Disinfect frequently touched surfaces at home, such as doorknobs and light switches.
Stay home when sick to avoid spreading bacteria to those around you.
Seek prompt treatment if you or your child develops symptoms — early treatment reduces the risk of complications and transmission.
According to Health Canada, hand hygiene is one of the most effective ways to prevent the spread of infectious diseases, including bacterial infections like strep.
Complications of Untreated Strep Infection
Leaving a strep infection untreated can lead to serious complications. The most well-known is rheumatic fever, which can cause lasting damage to the heart valves. This condition is preventable with timely antibiotic treatment.
Another potential complication is post-streptococcal glomerulonephritis, a type of kidney inflammation. While it is relatively uncommon, it underscores the importance of treating strep infections promptly. Children who have had strep throat repeatedly may be at higher risk.
In rare cases, Group A strep can cause necrotizing fasciitis — a severe infection sometimes called “flesh-eating disease.” This is a medical emergency that requires immediate hospital care. The World Health Organization’s resource on invasive Group A strep provides helpful detail on this serious condition.
When to See a Doctor
You should see your family doctor or visit a walk-in clinic if you or your child has a sudden, severe sore throat with fever, swollen glands, or difficulty swallowing. These are classic signs of a strep infection and deserve prompt attention.
In Canada, most provincial health plans cover visits to a family doctor or walk-in clinic for conditions like strep. If you do not have a family doctor, a walk-in clinic is a convenient and accessible option in most cities and towns.
Seek emergency care right away if you notice any of the following:
Difficulty breathing or swallowing
Drooling due to inability to swallow
A stiff neck
Severe, rapidly spreading skin redness or pain
High fever that does not respond to medication
Signs of confusion or extreme weakness
As always, this article provides general health information only. Please consult your doctor or a qualified healthcare provider for advice tailored to your specific situation.
Frequently Asked Questions About Strep Infection
What are the first signs of a strep infection?
The first signs of a strep infection usually include a sudden, severe sore throat and a fever above 38°C. You may also notice swollen lymph nodes in your neck and white or yellow patches on your tonsils. Unlike a cold, a strep infection typically does not cause a runny nose or cough.
Is a strep infection contagious?
Yes, a strep infection is very contagious and spreads through respiratory droplets from coughing, sneezing, or close contact. You can also pick up the bacteria by touching contaminated surfaces and then touching your face. You are generally contagious until you have been on antibiotics for at least 24 hours.
Can a strep infection go away on its own without antibiotics?
Mild strep symptoms can sometimes improve on their own, but doctors strongly recommend antibiotic treatment to prevent serious complications. Without treatment, a strep infection can lead to rheumatic fever or kidney problems. Always see a doctor if you suspect you have strep.
How long does a strep infection last with treatment?
With antibiotic treatment, most people with a strep infection start feeling better within 24 to 48 hours. The full course of antibiotics usually lasts 10 days, and it is important to finish all the medication. Stopping early increases the risk of the infection returning or spreading.
How is strep infection different from a regular sore throat?
A strep infection typically causes a much more sudden and severe sore throat compared to a sore throat caused by a cold virus. Strep usually comes without cold symptoms like a stuffy or runny nose. A quick throat swab test at your walk-in clinic can confirm whether it is strep or a viral infection.
Can adults get a strep infection, or is it just a children’s illness?
Adults can absolutely get a strep infection, though it is most common in school-age children. Adults who work with children or live in crowded environments are at higher risk. If you are an adult with a sudden, severe sore throat and fever, it is worth visiting your family doctor or a walk-in clinic for a strep test.
Key Takeaways
Strep infection is caused by Streptococcus bacteria, with Group A being the most common and most virulent type.
It spreads through respiratory droplets and close contact, especially in schools and crowded spaces.
Key symptoms include sudden sore throat, fever, swollen glands, and white patches on the tonsils — without cold-like symptoms.
Diagnosis is quick and easy with a throat swab test available at most walk-in clinics across Canada.
Antibiotic treatment is effective and helps prevent serious complications like rheumatic fever.
Good hand hygiene and staying home when sick are your best tools for preventing the spread of strep.
Always consult your family doctor or visit a walk-in clinic if you suspect a strep infection.
