Strep throat isn’t just a sore throat. It’s a bacterial infection caused by Group A Streptococcus (Streptococcus pyogenes), and it doesn’t go away on its own like a cold. If left untreated, it can lead to serious complications like rheumatic fever - a condition that can damage heart valves. The good news? It’s treatable. But only if you know when to act, what tests to ask for, and which antibiotics actually work.
How to Tell If It’s Strep Throat - Not Just a Cold
Not every sore throat is strep. Most are viral - from colds, flu, or even allergies. But strep throat has a distinct pattern. It hits fast. One day you’re fine, the next you can’t swallow without pain. Look for these signs:- Sudden, severe throat pain
- Fever over 100.4°F (38°C)
- White patches or pus on the tonsils
- Tender, swollen lymph nodes in the neck
- Red spots on the roof of the mouth (palatal petechiae)
The Right Way to Get Tested
You can’t diagnose strep by looking. You need a test. But not all tests are created equal. The Rapid Antigen Detection Test (RADT) (a throat swab that gives results in 10-30 minutes) is the first step. It’s accurate - over 95% specific - meaning if it’s positive, you’ve got strep. But it’s not perfect. About 5-15% of cases come back negative even when strep is there. That’s why guidelines from the CDC and the American Academy of Family Physicians say: if a child or teen tests negative, do a follow-up throat culture. Why? Because kids are more likely to develop complications if strep is missed. The throat culture (a lab test that grows the bacteria) takes 1-2 days, but it’s the gold standard. It catches what the rapid test misses. Newer molecular PCR tests (detect bacterial DNA) are popping up in clinics. They’re even more sensitive - 95-98% accurate - and give results in 24-48 hours. In 2024, the FDA approved a new rapid PCR test called Strep Ultra that works in 15 minutes. It’s not everywhere yet, but it’s coming fast. For adults with low risk - no fever, no pus, no swollen glands - some European guidelines say testing might not be needed. But in the U.S., the CDC still recommends testing anyone with symptoms. Why? Because the cost of missing one case of rheumatic fever is far higher than the cost of a $30 test.Which Antibiotics Work - and Which Don’t
Antibiotics don’t make you feel better instantly. But they do stop the infection from spreading and prevent serious complications. The goal isn’t just to feel okay - it’s to stop the bacteria for good. The first-line treatment? Penicillin V (500 mg twice daily for adults, 250 mg twice daily for kids) or Amoxicillin (a single daily dose for kids, up to 1000 mg for adults). Both are taken for 10 days. They kill the bacteria in 95% of cases. And they’re cheap - penicillin costs as little as $4 for a full course. If you’re allergic to penicillin, here’s what works:- Cephalexin - a cephalosporin, safe for most penicillin allergies
- Clindamycin - good for resistant cases, but watch for side effects like diarrhea
- Azithromycin - a 5-day course, but resistance is rising
What to Expect During Recovery
Once you start antibiotics, things move fast. - Within 24 hours: Fever drops. You’re no longer contagious. You can go back to school or work - as long as you’re fever-free and feeling better. - By 48 hours: Throat pain improves significantly. Swallowing gets easier. - By day 7: Most symptoms are gone. - By day 10: You’ve completed your antibiotics. The infection is cleared. Without antibiotics, symptoms last 7-10 days - and you’re contagious the whole time. You could pass it to your kids, your partner, your coworkers. But here’s the thing: feeling better doesn’t mean you’re cured. Stopping antibiotics early is the #1 reason strep comes back. In 5-15% of cases, the infection returns - sometimes worse - if the full course isn’t taken.When to Worry - Red Flags
Most people recover fine. But if you’re still sick after 48 hours of antibiotics, something’s wrong. See a doctor if:- Fever comes back after going away
- You develop a rash - especially a sandpaper-like one (could be scarlet fever)
- Swelling in the neck or difficulty breathing
- Severe pain on one side of the throat (could be a peritonsillar abscess)
Why This Matters - Beyond the Sore Throat
Strep throat causes 15 million doctor visits a year in the U.S. alone. It costs $350 million annually. But the real cost isn’t money - it’s what happens when we ignore it. Rheumatic fever - a preventable disease - still affects 325,000 children worldwide each year. It’s rare in the U.S. now, but it’s not gone. It’s just hidden. People who had untreated strep as kids can develop heart damage decades later. And antibiotic resistance? It’s real. The CDC reports that 30% of outpatient antibiotic prescriptions are unnecessary - mostly for viral infections. But when we under-treat strep, we create the same problem. We’re stuck between overuse and underuse. The answer? Test when needed. Treat with the right drug. Finish the course. Don’t guess. Don’t wait.
Common Mistakes - And How to Avoid Them
Parents and adults alike make the same errors:- Stopping antibiotics early. - You feel better, so you quit. Don’t. The bacteria might be hiding.
- Using old prescriptions. - That leftover amoxicillin from last year? Don’t use it. It might not be the right dose - or the right drug.
- Asking for antibiotics for every sore throat. - If you have a cough or runny nose, antibiotics won’t help. They’ll just make resistance worse.
- Not testing kids after a negative rapid test. - Always follow up with a culture if your child is under 18.
| Factor | Details |
|---|---|
| Most common age group | Children 3-9 years |
| Primary symptom | Sudden, severe sore throat without cough |
| First-line antibiotic | Penicillin V or amoxicillin for 10 days |
| Contagious period | Until 24 hours after starting antibiotics |
| Complication risk if untreated | 3% chance of rheumatic fever |
| Test accuracy (RADT) | 85-95% sensitivity, >95% specificity |
| Antibiotic resistance (azithromycin) | Up to 15% in some regions |
Frequently Asked Questions
Can you get strep throat without a fever?
Yes, but it’s rare. Fever is present in about 85% of confirmed cases. If you have a sore throat with no fever, it’s more likely viral. Still, if you have other classic signs - pus on tonsils, swollen glands, no cough - testing is worth considering.
How long does strep throat last with antibiotics?
Most people feel significantly better within 24-48 hours. Symptoms usually clear up completely in 7-10 days. But you must finish the full 10-day course, even if you feel fine. Stopping early increases the risk of relapse or complications.
Is strep throat contagious after 24 hours of antibiotics?
No. Once you’ve taken antibiotics for 24 hours and your fever is gone, you’re no longer contagious. You can return to school or work at that point - as long as you’re feeling well. But keep washing your hands and avoid sharing utensils for a few more days.
Can you test negative for strep and still have it?
Yes. Rapid tests miss about 5-15% of cases, especially in young children. If symptoms are strong but the rapid test is negative, a throat culture should be done - particularly for kids and teens. That’s the standard of care.
Why isn’t there a vaccine for strep throat?
The bacteria has over 200 different strains, each with a slightly different surface protein. Developing a vaccine that covers them all has proven extremely difficult. Research is ongoing, including a Phase II trial for an M-protein vaccine, but it’s years away - if it works at all.
