Strep Throat: A-to-Z Guide from Diagnosis to Treatment to Prevention

Tween boy holding his throat with a pained look on his fact. Could this be strep throat?


Some children fool their parents, with just a fever and a headache or stomachache. Others have the worst sore throat they can remember. Either way, strep throat should be treated with antibiotics.

What is it?

Strep throat is a bacterial infection of the throat. It is the most common infection caused by Streptococcus bacteria. Most sore throats, though, are caused by viral infections that are not improved by antibiotics. There are many strains of strep; some of them produce toxins that can lead to a scarlet fever rash. This rash is thought to be an allergic reaction to these toxins. Untreated, strep throat can sometimes lead to rheumatic fever. Kidney complications are among the other possibilities.

Who gets it?

Strep throat is most common in children between the ages of 5 and 15. It is unusual in children before the third birthday. Children younger than 3 can get strep infections, but usually not primarily of the throat. Strep throat is most common in the late fall, winter, and early spring, perhaps because children are in closer contact with each other during those months.


People with strep throat get sick an average of 3 days after they are exposed (range, 2–5 days). Illness usually begins suddenly, with a fever that peaks on the second day. Many children also have sore throat, headache, stomachache, nausea, or chills.

The throat and tonsils are often swollen and beefy red, covered in a gray/white/yellow coat. Red or purple spots may develop on the roof of the mouth. Lymph nodes in the neck may be tender.

In some people, strep throat is very mild, with only a few of these symptoms. In others, strep throat is severe.


A strep test, along with the appropriate history and physical findings, can assist in the diagnosis. In the absence of the test, strep throat is often confused with other throat infections, including those caused by adenovirus, Mycoplasma bacteria, or Epstein–Barr virus (mononucleosis).


Antibiotics are used to treat strep throat and to prevent many of its complications, including rheumatic fever. Ibuprofen can help children feel much better while the antibiotic is taking effect. The Centers for Disease Control and Prevention (CDC) recommends against treating sore throats with antibiotics unless the strep test is positive.


Treatment involves avoiding close contact with those who are contagious. Children should be kept out of school or daycare until they have been on antibiotics for 24 hours. Most people are no longer contagious 24 hours after starting the antibiotic. I also recommend getting a new toothbrush for children after they are no longer contagious but before they finish the antibiotics, to prevent re-infection.

Related concepts:

Strep pharyngitis, Acute pharyngitis, Exudative pharyngitis

Photo credit: Vitapix

Dr. Greene is a practicing physician, author, national and international TEDx speaker, and global health advocate. He is a graduate of Princeton University and University of California San Francisco.

Get Dr. Greene's Wellness Recommendations

Sign up now for a delightful weekly email with insights for the whole family.