Streptococcal Infection

Streptococcal infections are caused by bacteria that can affect your throat, skin, and in rare cases, deeper parts of your body. While most infections are mild and easily treated with antibiotics, understanding the symptoms and when to seek care is important for protecting your health.

Table of contents

• What is Streptococcal Infection?
• Types of Infections
• Symptoms
• How the Infection Spreads
• Who is at Risk?
• Diagnosis
• Treatment
• Possible Complications
• Prevention

What is Streptococcal Infection?

Streptococcal infections happen when a type of bacteria called Streptococcus enters your body and causes illness. There are different types of these bacteria, but Group A Streptococcus (also called Group A strep or GAS) is the most common type that makes people sick^[1][2]. The scientific name for this bacteria is Streptococcus pyogenes^[3].

Strep, Group A Strep, GAS, Streptococcus pyogenes, Group A Streptococcus

These bacteria are quite common and can live in your throat or on your skin without causing any problems. Some people carry the bacteria but never feel sick or show any symptoms. However, they can still spread the bacteria to others^[5][7].

• Throat
• Tonsils
• Skin
• Blood
• Deep tissues
• Muscles
• Lungs
• Heart

Types of Infections

Streptococcal bacteria can cause many different types of infections, ranging from mild conditions that are easy to treat to serious diseases that require hospital care^[4][5].

Common Mild Infections

Most streptococcal infections are mild and affect either your throat or your skin. Strep throat is one of the most common infections, causing pain and inflammation in your throat and tonsils. This condition accounts for a small portion of all sore throats but is the most common bacterial cause^[1][11].

Skin infections caused by strep bacteria include impetigo, which appears as yellow, crusty sores on your skin, particularly around your mouth and nose or on your arms and legs^[2][3]. Another skin condition is cellulitis, which causes painful, red, swollen areas on your skin^[4].

Scarlet fever can develop when someone with strep throat also gets a rash. The rash typically starts on your face and neck and spreads to other parts of your body. It feels rough, like sandpaper, and your tongue may become red and bumpy, which doctors call “strawberry tongue”^[3][8].

Serious Infections

In rare cases, strep bacteria can cause severe, life-threatening infections called invasive group A streptococcal disease (iGAS)^[5][10]. These infections happen when bacteria invade deeper parts of your body, such as your blood, muscles, or lungs.

Necrotizing fasciitis, sometimes called “flesh-eating disease,” is a serious infection that affects the deep layers of your skin and the tissue beneath it. Early signs include severe pain, swelling, and redness at a wound site, along with fever^[10][14].

Streptococcal toxic shock syndrome is another severe condition that progresses rapidly. It causes low blood pressure, shock, and damage to organs like your kidneys, liver, and lungs. Early symptoms may include fever, dizziness, confusion, rash, and abdominal pain^[10][14].

About 9,000 to 11,500 cases of invasive strep disease occur in the United States each year, resulting in 1,000 to 1,800 deaths. Approximately 20 percent of patients with necrotizing fasciitis and 60 percent with toxic shock syndrome die from these infections^[10].

Symptoms

The symptoms you experience depend on where the infection is in your body. One common symptom across different types of strep infections is fever^[3][7].

Throat Infection Symptoms

When strep bacteria infect your throat, you typically experience a sore throat that comes on quickly. The pain usually appears suddenly rather than gradually^[1][11]. Swallowing becomes painful, and your throat and tonsils may appear red and swollen. You might notice white patches, spots, or streaks of pus on your throat and tonsils^[1][11].

Other symptoms that may accompany strep throat include swollen, tender lymph nodes in your neck, headache, chills, loss of appetite, nausea and vomiting, and body aches^[1][11]. You may also develop tiny red spots on the roof of your mouth^[11].

It’s important to note that strep throat typically does not cause a cough. If you have a cough along with your sore throat, you probably have a viral infection instead^[11][13].

Skin Infection Symptoms

Strep infections on your skin can cause different symptoms. With impetigo, you’ll see small, red to purple sores on your nose, mouth, arms, or legs. These sores leak a clear to yellow fluid or pus and develop crusty yellow scabs. Your skin may feel itchy^[4][7].

Cellulitis causes a painful red area on your skin that may feel warm to touch and appear swollen^[2][4].

Severe Infection Symptoms

Serious strep infections can cause severe symptoms including severe muscle aches, nausea and vomiting, shortness of breath, severe pain that spreads beyond a wound, skin that changes color from red to purple, large wounds or blisters, and black spots forming on your skin^[3][4].

How the Infection Spreads

Strep bacteria are very contagious and spread easily from person to person^[4][5]. Understanding how these bacteria spread can help you protect yourself and others.

The most common way strep spreads is through respiratory droplets. When someone with a strep infection talks, coughs, or sneezes, they release tiny droplets into the air that contain the bacteria. You can get sick if you breathe in these droplets or if you touch something that has droplets on it and then touch your mouth or nose^[5][7].

Direct contact with an infected person can also spread the bacteria. This happens through close contact like kissing or touching infected skin sores or coming into contact with fluid from these sores^[5][10].

The risk of spreading strep is greatest when someone is actively ill, such as when they have strep throat or an infected wound. People who carry the bacteria but show no symptoms are much less likely to spread it to others^[10][14].

Once you start taking antibiotics, you become less contagious within about 24 hours. However, people who don’t take antibiotics can spread the bacteria for a couple of weeks^[23][18]. It usually takes about 2 to 5 days after exposure to the bacteria before you start experiencing symptoms^[13][23].

Who is at Risk?

Anyone can get a streptococcal infection, but certain groups of people are more likely to become infected^[4][5].

Children are the most commonly affected group. Strep throat is most common in school-aged children between the ages of 5 and 15 years old, though it can also affect younger children aged 3 to 9^[1][11][13]. The number of strep throat cases drops significantly in adults, where only 10 to 15 percent of sore throats are caused by strep bacteria^[13].

People who are in close contact with school-aged children have a higher risk of getting strep. This includes siblings, parents, teachers, and other caregivers^[11][13].

Being in crowded settings increases your risk of exposure. Group settings like households, daycares, schools, colleges, and military barracks make it easier for the bacteria to spread from person to person^[11][13].

Certain factors can increase your risk of developing serious strep infections. These include being 65 years or older, having a weakened immune system, having chronic health conditions like diabetes, heart disease, kidney disease, liver disease, or lung disease, having cancer, being pregnant or having recently given birth, having open sores or wounds, having obesity, injecting drugs, experiencing homelessness, or living in long-term care facilities^[5][7][10].

Some viral infections, like flu or chickenpox, can also increase your risk of getting a serious strep infection^[5][7].

Diagnosis

Your doctor cannot tell if you have strep throat just by looking at your symptoms or examining your throat. Testing is necessary to confirm whether bacteria or a virus is causing your illness^[13].

During your visit, your doctor will perform a physical exam and look for signs of strep infection. For throat infections, they will examine your throat and tonsils, check for swollen lymph nodes in your neck, and look for other symptoms^[1][12].

To confirm strep throat, doctors use one or more tests. The most common is a rapid antigen detection test (rapid strep test). Your doctor will use a sterile swab to collect a sample from the back of your throat and tonsils. This may cause you to gag but shouldn’t be painful. The test can detect strep bacteria in minutes by looking for specific substances from the bacteria^[12][13].

If the rapid test is negative but your doctor still suspects strep, especially in children aged 3 years or older, they may do a throat culture. This test uses the same type of throat swab, but the sample is sent to a laboratory where it is cultured to see if bacteria grow. Results can take up to two days. A throat culture is considered the gold standard for diagnosing strep throat^[12][13].

Some doctors may also use a molecular test, also called a PCR test, which is done using a throat swab sample^[12].

For skin infections, your doctor may take a swab from the infected area or other tissue samples for testing^[4][8].

Treatment

The main treatment for streptococcal infections is antibiotics. These medications kill the bacteria and help you recover faster^[2][4][12].

Antibiotic Treatment

Doctors most often prescribe penicillin or amoxicillin to treat strep infections. These are the top choices because they are safe, inexpensive, and work well against strep bacteria^[15][17]. If you’re allergic to penicillin, your doctor may prescribe other antibiotics such as azithromycin, cephalosporins, clarithromycin, or clindamycin^[17].

Most antibiotic treatments for strep throat last about 10 days. You should start feeling better within a day or two after starting the medicine^[11][12][17].

It’s very important to take all of your medicine, even if you start feeling better before finishing the prescription. Stopping antibiotics too early can allow some bacteria to survive, which might lead to the infection coming back or cause serious complications. If you don’t finish your antibiotics, you also remain contagious for longer^[10][12][14].

After taking antibiotics for 24 hours, you are no longer contagious and can usually return to school or work if you feel well and don’t have a fever^[12][18][27].

Symptom Relief

While antibiotics fight the infection, there are several things you can do to feel more comfortable. Over-the-counter pain relievers like acetaminophen (Tylenol) or ibuprofen (Advil, Motrin) can help relieve throat pain and reduce fever^[12][17][27].

Drinking plenty of fluids helps keep your throat moist and prevents dehydration. Warm fluids like tea or soup may feel soothing, while some people prefer cold foods like popsicles or ice cream^[19][27]. Gargling with warm salt water several times a day can help reduce swelling and relieve pain. Mix half a teaspoon of salt in one cup of warm water^[27].

Getting plenty of rest is important to help your body fight the infection. Stay home from work or school to rest and avoid spreading the bacteria to others^[19][27].

Serious Infections

Serious strep infections like necrotizing fasciitis need to be treated in a hospital with antibiotics. These patients often require surgery to remove dead, infected tissue^[8][18].

Possible Complications

While most strep infections are mild, untreated infections can lead to serious complications^[1][11].

Rheumatic fever is one of the most serious complications of strep throat. This condition can cause painful, swollen joints and lead to heart valve damage, though this damage may not appear for many years. Children with rheumatic fever may have uncontrollable, jerky movements of their arms and legs^[1][8][11].

Other complications can include kidney inflammation (glomerulonephritis), sinus and ear infections, and abscesses around the tonsils^[1][2][11].

Taking antibiotics as prescribed helps prevent these complications. If taken within 48 hours of when symptoms begin, antibiotics reduce the severity of symptoms, the risk of complications, and the likelihood of spreading the infection to others^[12][13].

Prevention

There is no vaccine to prevent strep infections, but you can take several steps to reduce your risk of getting sick or spreading the bacteria to others^[5][22].

Good Hygiene Practices

Washing your hands often with soap and water is one of the most important ways to prevent strep infections. Always wash your hands after coughing, sneezing, or touching shared objects in public places^[7][22].

Cover your mouth and nose with a tissue when you cough or sneeze, then throw the tissue away immediately. If you don’t have a tissue, cough or sneeze into your elbow rather than your hands^[22].

Avoid touching your face, particularly your mouth and nose, to minimize the chance of introducing bacteria into your body^[24].

When Someone is Sick

If someone in your household has a strep infection, take precautions to limit exposure. Encourage them to stay home until they are no longer contagious^[24].

Avoid sharing utensils, cups, plates, or other personal items with someone who has strep. After someone who is sick uses dishes or utensils, wash them thoroughly with hot, soapy water. Once washed, these items are safe for others to use^[14][22][27].

Clean commonly touched surfaces to prevent the spread of germs^[24].

Wound Care

Taking care of cuts and wounds properly can help prevent skin infections. Clean all minor cuts and injuries with soap and water. Cover any draining or open wounds with clean, dry bandages until they heal. Wash your hands before touching any wound^[22].

Boost Your Immune System

A strong immune system helps your body fight off infections. Get plenty of sleep, eat a balanced diet rich in fruits and vegetables, and stay physically active. Consider taking a daily multivitamin if your doctor approves^[24].

Stay hydrated by drinking plenty of water throughout the day. This helps keep your throat moist and healthy, reducing the likelihood of irritation and infection^[24].

Seek Prompt Treatment

If you suspect you have strep throat, see your doctor quickly for testing and treatment. Early treatment with antibiotics prevents complications and stops the spread of bacteria to others^[24].