Strep Throat: How to Diagnose, Treat with Antibiotics, and Know When You're Recovered

When your throat suddenly feels like sandpaper and swallowing hurts so much you avoid even sipping water, it’s easy to assume it’s just a cold. But if you also have a fever over 100.4°F, swollen glands in your neck, and no cough or runny nose, you might be dealing with strep throat. Unlike the common cold, strep is a bacterial infection caused by Group A Streptococcus - and it doesn’t just go away on its own. Left untreated, it can lead to serious complications like rheumatic fever, which can damage your heart valves. The good news? With the right diagnosis and antibiotics, most people bounce back in under a week.

How to Tell If It’s Strep - Not Just a Cold

1. Your sore throat came on fast - usually within hours, not days.
2. You have a fever above 100.4°F (38°C).
3. Your tonsils are swollen and coated with white patches or pus.
4. Your neck lymph nodes are tender to the touch.
5. You have tiny red spots on the roof of your mouth (palatal petechiae).
6. You have no cough, no runny nose, and no red eyes.

That last point is critical. If you’re coughing or congested, it’s almost certainly viral - not strep. Doctors use this pattern to rule out strep in about 90% of cases without even testing. This is called the Centor criteria. If you have three or four of these signs, your chance of having strep jumps to 40-60%. But don’t guess. Testing is the only way to be sure.

Testing for Strep Throat: What Works and What Doesn’t

The fastest test is the rapid antigen detection test (RADT). A swab from your throat gives results in 10 to 30 minutes. It’s over 95% specific, meaning if it’s positive, you’ve got strep. But it can miss up to 15% of cases - especially in kids under 5, where bacterial load is lower. That’s why guidelines from the CDC say: if the test is negative in a child or teen, you still need a throat culture.

The throat culture is the gold standard. It takes 18 to 48 hours, but it catches almost all cases - 90-95% sensitivity. Most clinics still use it as a backup to the rapid test. In urgent care centers and hospitals, molecular PCR tests are becoming more common. They’re even more sensitive (95-98%) and give results in 24 to 48 hours. A new FDA-approved test called Strep Ultra (launched March 2024) delivers results in 15 minutes with 98% accuracy - and it’s starting to replace older rapid tests.

Adults with low risk (one or two Centor criteria) and a negative rapid test usually don’t need further testing. But children? Always confirm. Their risk of rheumatic fever is real.

Antibiotics: Which Ones Work and Why Timing Matters

Antibiotics aren’t just for feeling better faster - they prevent life-threatening complications. The first-line treatment is penicillin V (500 mg twice daily for adults) or amoxicillin (once daily for kids, up to 1000 mg for adults). Both are taken for 10 days and clear the infection in 95% of cases. They’re cheap - a 10-day course of generic penicillin costs as little as $4.

If you’re allergic to penicillin, alternatives include:

• Cephalexin - a first-generation cephalosporin, taken twice daily.
• Clindamycin - used when resistance is suspected, taken three times daily.
• Azithromycin - a 5-day course, but it’s less effective (85-90% success) and resistance is rising in some areas.

Why 10 days? Because strep bacteria can hide in the tonsils. Stopping early - even if you feel fine - leaves behind survivors. These survivors can cause a relapse (5-15% of cases) or spread resistance. Studies show 99% of infections are fully cleared when patients finish the full course. When they don’t? Relapse rates jump to 30%.

Antibiotics don’t just help you - they stop you from spreading it. Within 24 hours of starting antibiotics, you’re no longer contagious. Without treatment, you can spread strep for up to 10 days.

Recovery Timeline: What to Expect Day by Day

With antibiotics, here’s what happens:

• Day 1: You start the antibiotic. Symptoms won’t change yet.
• Day 2: Fever drops. Swallowing gets easier. This is when you can return to school or work - if you’ve been fever-free for 24 hours.
• Day 3-4: Throat pain fades. Swollen glands begin to shrink.
• Day 5-7: Most symptoms are gone. You feel back to normal.
• Day 10: Finish your antibiotics. Even if you feel great, don’t stop early.

Without antibiotics? Symptoms last 7-10 days, and you’re contagious the whole time. The risk of complications - like a peritonsillar abscess (a pus-filled pocket behind the tonsil) - increases. That happens in 1-2% of untreated cases and often requires surgery.

Don’t be fooled by feeling better. A 2023 study in JAMA Pediatrics found 40% of parents stop antibiotics as soon as their child stops crying during swallowing. That’s dangerous. It’s not just about comfort - it’s about preventing long-term damage.

When to Call the Doctor Again

If you’ve been on antibiotics for 48 hours and you’re still feverish, in severe pain, or having trouble breathing or swallowing, go back. You might have a complication like:

• Peritonsillar abscess - swelling that pushes the tonsil sideways.
• Scarlet fever - a rash that follows strep, often on the chest and groin.
• Rheumatic fever - rare, but can cause joint pain, heart inflammation, or involuntary movements.

Also, if you develop nausea, vomiting, or a rash after starting antibiotics, you may be having an allergic reaction. Don’t ignore it.

Common Mistakes That Make Things Worse

People make the same mistakes over and over:

• Sharing antibiotics - 8% of adults admit to giving leftover meds to family members. That’s how resistance spreads.
• Using old prescriptions - 12% of people in a 2023 CDC survey used leftover antibiotics for a new sore throat. But if it’s not strep? You’re just poisoning your body with useless drugs.
• Skipping the test - many doctors skip testing for adults, assuming it’s viral. But if it’s strep and you’re untreated? You could be the silent spreader.
• Staying home too long - if you’ve been on antibiotics for 24 hours and your fever is gone, you’re no longer contagious. There’s no need to miss 5 days of work or school.

And here’s something surprising: kids under 3 almost never get strep throat. Their immune systems don’t react the same way. So if your toddler has a sore throat, it’s almost always viral. No need to test unless symptoms are severe.

What’s Changing in 2026?

Research is moving fast. The CDC is tracking rising resistance to macrolides like azithromycin - now at 15% in some U.S. regions. Clindamycin resistance is creeping up too. That’s why penicillin remains the go-to: resistance is still below 0.5%.

Point-of-care PCR tests are getting cheaper and faster. By 2026, 40% of urgent care centers expect to use them routinely. That means same-day confirmation without waiting 24 hours.

And yes - there’s talk of a vaccine. A vaccine targeting the M-protein of Group A strep is in Phase II trials. But with over 200 different strains, it’s like chasing a moving target. Don’t hold your breath - prevention still comes down to good hygiene and proper treatment.

Final Takeaway

Strep throat isn’t just a sore throat. It’s a bacterial infection that needs antibiotics - not home remedies, not honey and lemon, not even garlic. If you have the classic signs (fever, no cough, swollen glands), get tested. If it’s positive, take every pill. Don’t stop early. Don’t share. Don’t guess. You’re not just helping yourself - you’re protecting others. And you’re preventing damage that could last a lifetime.