Strep throat causes a sudden, severe sore throat along with fever, swollen tonsils, and tender lymph nodes in the neck. Unlike a typical cold-related sore throat, strep comes on fast and usually doesn’t include a cough or runny nose. It’s caused by group A Streptococcus bacteria and is most common in children ages 5 to 15, though adults get it too.
The Main Symptoms
The hallmark of strep throat is throat pain that appears quickly, often within a day. Swallowing becomes painful, and the tonsils look red and swollen, sometimes with visible white patches or streaks of pus. You may also notice tiny red spots on the roof of your mouth, toward the back. The lymph nodes on the front of your neck often feel swollen and tender to the touch, and fever is common.
Body aches and headache can accompany the throat symptoms, making it easy to mistake early strep for the flu. But the absence of typical cold symptoms is actually one of the most useful clues.
How Strep Looks Different in Children
Kids with strep throat often have symptoms that don’t seem throat-related at all. Stomach pain, nausea, and vomiting are common in younger children and may be the most prominent complaints, sometimes overshadowing the sore throat itself. Some children also develop a distinctive rash known as scarlet fever: a rough, sandpaper-textured rash that typically starts on the trunk and spreads outward. Scarlet fever is not a separate illness; it’s strep throat that happens to produce a skin reaction.
Because children can present so differently, strep is easy to miss if you’re expecting the classic adult version of a bad sore throat with nothing else going on.
Signs It’s Probably Not Strep
Certain symptoms actually point away from strep and toward a viral infection. If you have a cough, runny nose, hoarseness, or pink eye alongside your sore throat, a virus is the more likely cause. Strep throat is a focused infection: it hits the throat and lymph nodes hard but generally doesn’t cause the upper respiratory symptoms you’d associate with a cold.
This distinction matters because antibiotics treat strep but do nothing for viral sore throats. Roughly 70 to 80 percent of sore throats in adults are viral, so the presence or absence of these “viral clues” helps determine whether testing is worthwhile.
How Strep Is Diagnosed
Doctors can’t diagnose strep by looking at your throat alone. The standard approach is a rapid strep test, which involves swabbing the back of the throat and getting results in minutes. Throat culture, where the swab is sent to a lab, remains the most accurate test and is considered the gold standard.
For children age 3 and older, current guidelines recommend that a negative rapid test be backed up with a throat culture, since rapid tests can miss some cases. For adults, a follow-up culture after a negative rapid test isn’t routinely needed because the complication that matters most, rheumatic fever, is rare in older age groups.
What Doctors Look For
Clinicians use a scoring system to decide who needs testing. The factors that raise suspicion for strep include fever above 100.4°F (38°C), swollen or pus-covered tonsils, tender lymph nodes in the front of the neck, and the absence of a cough. Being between ages 3 and 14 also adds to the likelihood. The more of these features you have, the higher the chance of a positive test, but none of them alone confirms the diagnosis.
Symptom Timeline
Strep symptoms typically appear 2 to 5 days after exposure to the bacteria. Without treatment, symptoms generally resolve on their own within about a week, but the person remains contagious longer and faces a higher risk of complications. With antibiotics, most people start feeling noticeably better within 1 to 2 days and are no longer contagious after about 12 to 24 hours of treatment.
Complications Worth Knowing About
The main reason strep throat gets treated with antibiotics isn’t just symptom relief. It’s to prevent rheumatic fever, a serious inflammatory condition that can develop 1 to 5 weeks after an untreated strep infection. Rheumatic fever causes joint pain (most often in the knees, ankles, elbows, and wrists), fatigue, fever, and sometimes jerky, involuntary body movements. In more severe cases it affects the heart, potentially causing chest pain, a fast heartbeat, shortness of breath, or lasting heart valve damage.
Another possible complication is kidney inflammation, which can cause dark or reduced urine, swelling in the face or ankles, and fatigue. Peritonsillar abscess, a pocket of pus forming near the tonsil, is a more immediate complication that causes worsening one-sided throat pain, difficulty opening the mouth, and a muffled voice. These complications are uncommon with prompt treatment but are the reason strep throat isn’t simply left to resolve on its own.