Quick answer: Symptoms often fade on their own within about a week — but that is not the same as the infection being gone. Untreated strep leaves Streptococcus pyogenes bacteria in the throat, keeps you contagious far longer, and carries a real risk of complications including rheumatic fever. Strep throat should be treated with antibiotics.
Feeling Better Is Not the Same as Being Cured
This is the single most important distinction with strep. Your immune system can suppress the symptoms of a strep infection without clearing the bacteria. You stop feeling sick, so you assume it resolved — while the underlying infection continues.
Antibiotics do three things that waiting does not:
- Prevent complications. This is the main reason we treat.
- Cut the contagious period. You are no longer contagious after roughly 24 hours on antibiotics, versus 2 to 3 weeks untreated.
- Shorten symptoms by roughly a day, which is the smallest of the three benefits.
What Untreated Strep Can Cause
Complications are uncommon but serious:
- Acute rheumatic fever — an inflammatory reaction that can permanently damage heart valves. It typically appears 2 to 4 weeks after an untreated infection and is most common in school-age children.
- Post-streptococcal glomerulonephritis — kidney inflammation causing dark urine and swelling.
- Peritonsillar abscess — a pocket of pus beside the tonsil that may need drainage.
- Scarlet fever — a sandpaper-textured rash accompanying the infection.
- Spread of infection to the sinuses, middle ear, or lymph nodes.
Rheumatic fever became rare in the United States precisely because strep is routinely tested for and treated. That protection depends on people actually getting tested.
Telling Strep From a Virus
Most sore throats are viral and need no antibiotic. Strep tends to look different:
- Sudden onset of a severe sore throat, rather than a gradual build
- Pain on swallowing
- Fever, often 101°F or higher
- Red, swollen tonsils, sometimes with white patches or streaks of pus
- Tiny red spots on the roof of the mouth
- Swollen, tender lymph nodes in the front of the neck
- Headache, stomach ache, or nausea — common in children
What argues against strep: cough, runny nose, hoarseness, pink eye, or mouth ulcers. Those point to a virus. This is why we test rather than guess — the overlap is genuinely difficult to call by eye.
Testing and Treatment
A rapid antigen test on a throat swab returns results in minutes. A negative rapid test in a child is often confirmed with a throat culture, which takes 24 to 48 hours and catches cases the rapid test misses.
If the test is positive, treatment is typically a 10-day course of penicillin or amoxicillin. Alternatives exist for penicillin allergy.
Finish the entire course. Most people feel better in 24 to 48 hours and are tempted to stop. Completing all 10 days is what prevents rheumatic fever. Stopping early is the most common way treatment fails.
For comfort while the antibiotic works: warm salt-water gargles, cold fluids or popsicles, throat lozenges for children old enough to use them safely, and acetaminophen or ibuprofen for pain. Replace your toothbrush after 24 hours on antibiotics.
When to Seek Care Urgently
- Trouble breathing or swallowing your own saliva
- Inability to open the mouth fully, or a muffled voice
- Swelling on one side of the throat, or a neck that is stiff or swollen
- No improvement after 48 hours on antibiotics
- A rash, dark urine, or joint swelling in the weeks after an infection
- Repeated strep infections — worth a conversation about next steps
Frequently Asked Questions
How long is strep contagious?
About 24 hours after starting antibiotics. Untreated, you can remain contagious for 2 to 3 weeks. Most schools require 24 hours of treatment plus no fever before returning.
Can adults get strep throat?
Yes, though it is most common between ages 5 and 15. Adults living with school-age children are exposed most often. Rheumatic fever risk is lower in adults but treatment is still standard.
Do I need to be retested after treatment?
Usually not, if symptoms resolve. Repeat testing is reserved for people with recurring infections or a history of rheumatic fever.
Can you have strep without a fever?
Yes. Fever is common but not universal, particularly in adults and in people who have taken fever-reducing medicine. Testing is the only reliable way to know.
Get a Rapid Strep Test at IM&PC
A sore throat that came on fast deserves a test, not a wait. IM&PC sees patients of every age at both of our Mississippi clinics — New Albany and Saltillo. Call to schedule, or walk in during urgent care hours.
This article is general health information from Internal Medicine & Pediatric Clinic and is not a substitute for individual medical advice. Talk with your provider about your own situation. If you think you are facing a medical emergency, call 911.