Is it Strep Throat?

Or Just a Cold...

Doctor using tongue depressor to allow examination of young boy's throat
How can you tell if you have a sore throat that is strep or if it is a viral infection?. ADAM GAULT/SPL / Getty Images

Strep throat is a relatively common infection in children, particularly in the winter months. While most sore throats are caused by viruses, they are often misdiagnosed as strep throat. In fact, up to 73 percent of people are given antibiotics, which are useless against viruses. The problem is that misuse of antibiotics is the primary reason for the development of antibiotic-resistant superbugs.

Accurate diagnosis of strep throat is extremely important for two reasons.

An appropriate diagnosis of strep throat is needed to avoid the unnecessary use of antibiotics which can result in the emergence of antibiotic resistance (and the chance that at a later date you will develop an infection for which antibiotics are not effective.) Yet a positive diagnosis and treatment are critical to avoid the possible long-term complications of an untreated strep infection.

Knowing how important the distinction is, how can you tell if it's strep or a sore throat due to a virus?

What is Strep Throat?

Strep throat, also known as “streptococcal pharyngitis,” is a bacterial infection of the inside of the throat. It is caused by the bacterial species Streptococcus pyogenes, also known as Group A strep.

Strep throat is a common affliction among school-age children (ages 5 to 15), comprising up to 30 percent of sore throats in this age group. Strep, however, can affect anyone from young infants to elderly adults.

Strep throat is responsible for only 5 to 15 percent of sore throats in adults.

Common Symptoms of Strep Throat

Symptoms of strep throat may include:

  • Sore throat (A sore throat due to strep is often more severe than those with viral infections, but can be similar to those with mono)
  • White spots on the throat
  • Red or purple spots on the roof of the mouth (on the palate)
  • Fever - A temperature of 101 to 104 degrees F is not uncommon with Strep, especially in younger children
  • Headache
  • Swollen lymph nodes - Tender, enlarged lymph nodes are often present in the "anterior cervical" lymph nodes, in contrast to the swollen posterior cervical nodes seen with mono
  • Nausea and vomiting
  • Abdominal pain
  • Rash

Strep vs Viral Infections—Is it Strep Throat or Just a Cold?

One of the primary purposes of seeing your doctor with a sore throat is to distinguish whether the infection is due to strep, or is instead caused by one of several viruses, including those which cause the common cold. A sore throat, in general, is more likely to be due to a viral infection than strep.

Symptoms often seen with viruses but not frequent with strep throat include:

In contrast, symptoms more likely to be present with strep than a virus include:

  • White discharge on the throat and tonsils (pus)
  • A "strawberry" appearance to the tongue
  • A higher fever (a temperature of 100 F or greater)
  • Large, tender, swollen lymph nodes in the neck

It's been found that if four conditions are present, the probability of a strep throat is 56 percent, whereas if none of these conditions are present, the chance that a sore throat is due to strep is only 2.5 percent.

These include:

  • Fever higher than 99.9 F
  • Patches of pus in the throat
  • Swollen lymph nodes in the neck
  • Absence of cough

How Does Strep Throat Differ From Scarlet Fever?

Many people wonder about the differences between an ordinary sore throat and scarlet fever. Scarlet fever involves the same bacteria which causes similar symptoms. With scarlet fever, however, the bacteria release a toxin which results in the characteristic rash involving the face and chest. Redness of the face is common, and has been described as having a "slapped cheek" appearance. The rash consists of small elevated spots which have a sandpaper consistency (a sandpaper rash) usually most pronounced on the chest.

Scarlet fever is treated the same as a strep throat.

Other Strep Infections

We often think of strep primarily with sore throats, but other infections can be caused by group A strep as well. For example, impetigo is a skin infection caused by strep (as well as some other bacteria) and can also cause complications similar to strep throat.

Diagnosis of Strep

In addition to taking a history and doing a physical exam, your doctor will likely order a strep screen and a throat culture. The strep screen will provide results right away, and can guide your physician to begin treatment if positive. A strep culture can take 48 hours or more, but sometimes finds a strep infection which does not show up on a strep screen.

In some cases, if the diagnosis if uncertain, for example, if a strep screen is negative but clinical signs suggest strep is very likely, a white blood cell count may be done. Looking at the type of white blood cells present in your blood can help your doctor decide whether your infection appears to be bacterial or viral.

Treatments for Strep Throat

Antibiotics prescribed for strep throat most commonly include amoxicillin or penicillin V, but several other options are available as well.

To help people cope with the symptoms there are several home remedies for a sore throat that do not fight the infection but can make you more comfortable until the infection subsides. Medications such as Tylenol (acetominophen) or Advil (ibuprofen) can also ease symptoms.

Recurrent Strep Throat

Sometimes strep throat becomes recurrent, yet it's important to treat each infection to prevent complications. For those who have had many infections, sometimes considered severe or more infections in one year, a tonsillectomy should be considered.

Importance of Making An Accurate Diagnosis of Strep Throat

In our fast paced society, many people do not wish to take the time to go to the clinic and have a strep screen done. It's not uncommon to have people call and request a prescription for antibiotics for a sore throat that "may" be strep. Other people view strep as a nuisance that will go away on its own (and it often does) without antibiotic treatment. Unfortunately, this practice can be dangerous on both sides of the equation. What are the consequences of "overtreating" a sore throat that isn't strep or undertreating an infection that is strep?

Complications of Untreated Strep Throat

An untreated strep throat infection can lead to some serious complications.  These complications can be broken down into two major categories:

Suppurative (pus-forming) complications may include:

  • Peritonsillar abscess - A peritonsillar abscess consists of an abscess (a walled-off collection of bacteria which form a bump) that forms behind and in front of the tonsil. This uncommon complication of strep usually occurs two to eight days after the sore throat.

Non-suppurative complications include:

  • Rheumatic fever - Rheumatic fever isn't due to a strep infection itself, but rather is due to antibodies your body forms against the strep bacteria which react against your own tissues. Rheumatic fever can affect your heart, joints, and brain and result in chronic rheumatic heart disease.
  • Post-streptococcal glomerulonephritis - Glomerulonephritis is a kidney condition which may occur after a strep throat or impetigo due to strep and can be very serious.
  • Toxic shock syndrome - Group A strep is one of the possible causes of toxic shock syndrome (TSS.) TSS is uncommon after a strep throat infection and is often related to tampon use in young women.
  • Henoch-Schonlein purpura - Henoch-Schonlein purpura is an autoimmune syndrome associated with Group A strep roughly 40 percent of the time, and results in low platelets and bruising among other serious symptoms involving the kidneys and digestive tract.

Complications of Using Antibiotics for a Viral Sore Throat

Treating a viral infection with antibiotics can, in some ways, be just as dangerous as ignoring a true strep infection. Part of the reason is the emergence of resistant bacteria mentioned earlier. But even for an individual person, this practice can carry risks. Antibiotics are not without side effects and some of these can be serious. In the setting of a true infection, the benefits usually outweigh the risks, but when the antibiotic is not needed, the risks clearly outweigh the benefits.

Allergic reactions to antibiotics can be uncomfortable (with a rash or hives) but can also be life-threatening at times, leading to anaphylactic shock (the worst type of allergy.) Complications of antibiotic treatment such as Stevens-Johnson syndrome may also occur. With this condition, the body's response to an antibiotic can lead to symptoms of skin sloughing which resembles a severe burn and can sometimes even be fatal.

When Should You See Your Doctor?

If you have a sore throat with fever or exhibit any of the other characteristic symptoms, contact your doctor or pediatrician to see if you should be examined or tested for strep throat.


Arslansoyu Camlar, S., Soylu, A., Akil, I. et al. Henoch-Schonlein Purpura, Post-Streptococal Glomerulonephritis and Acute Rheumatic Carditis after Group A Beta-Haemolytic Streptococcal Infection. Paediatric and International Child Health. 2017 Feb 6. (Epub ahead of health).

Kalra, M., Higgins, K., and E. Perez. Common Questions About Streptococcal Pharyngitis. American Family Physician. 2016. 94(1):24-31.

Kliegman, Robert M., Bonita Stanton, St Geme III Joseph W., Nina Felice. Schor, Richard E. Behrman, and Waldo E. Nelson. Nelson Textbook of Pediatrics. 20th Edition. Philadelphia, PA: Elsevier, 2015. Print.