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Sore Throat: Strep vs Cold and When to Worry

Most sore throats are caused by viruses and resolve on their own within a week. Group A strep (strep throat) accounts for only 5–15% of sore throats in adults and 15–35% in children. Key signs pointing toward strep: sudden-onset severe pain, fever, swollen lymph nodes, and no cough. A rapid strep test or throat culture is needed to confirm — antibiotics only help confirmed bacterial infections.

Written by Gale Editorial · grounded in the cited clinical sources below · Updated 2026-06-15. How we write.

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What Causes a Sore Throat?

The vast majority of sore throats are caused by viruses — rhinovirus, coronavirus, respiratory syncytial virus, and Epstein-Barr virus (the cause of mono), among others 1. In adults, only 5–15% of pharyngitis cases are due to Group A Streptococcus (GAS), the bacterium responsible for strep throat; in children aged 3–9, that figure rises to 15–35% 2.

Because viral and bacterial sore throats can look similar, clinical examination alone is not reliable enough to distinguish them 1. That distinction matters: antibiotics work against bacteria but have no effect on viruses, and unnecessary antibiotic use carries real harms including severe allergic reactions, *Clostridioides difficile* infection, and the spread of antimicrobial resistance 3.

Strep vs Cold: How to Tell the Difference

Certain features reliably shift the odds toward or away from strep throat. Clinicians use a validated tool — the Modified Centor (McIsaac) score — to combine these features into a probability estimate 4.

Features that raise strep probability (1 point each): - Fever (38 °C / 100.4 °F or higher) - Tonsillar swelling or exudate (white patches) - Swollen, tender lymph nodes at the front of the neck - Absence of cough - Age 3–14 years (an additional point in the McIsaac modification)

Features that point toward a viral cause: - Gradual onset of throat pain - Runny nose, nasal congestion, or post-nasal drip - Cough or hoarseness - Conjunctivitis (pink eye) - Ulcers or blisters in the mouth

A Modified Centor score of 4 correlates with roughly a 57% probability of strep; a score of 0 or 1 makes strep unlikely enough that testing is generally not recommended 4. Strep throat in children can also include headache, stomachache, or nausea — symptoms less common in adults 3.

Infectious mononucleosis (mono), caused by Epstein-Barr virus, can closely mimic strep and accounts for about 2% of sore throats in adults 1. Mono is worth considering when a teenager or young adult has a prolonged sore throat, marked fatigue, and swollen lymph nodes — particularly if a strep test comes back negative.

Testing: Rapid Strep Test and Throat Culture

Only a rapid antigen detection test (RADT) or throat culture can confirm strep throat 3. Clinical judgment alone — no matter how experienced the clinician — is insufficient.

Rapid strep test: Results are available in minutes. When performed in a clinical setting, the test has a pooled sensitivity of approximately 85% and specificity of approximately 96% 2. A positive result is highly reliable. A negative result in a child or teenager, however, should be followed by a throat culture, because rapid tests can miss roughly 1 in 7 true strep infections in this age group 3.

Throat culture: The gold standard. Takes 24–48 hours but detects infections a rapid test may miss. For adults, guidelines do not require a backup culture after a negative rapid test, because strep is less common in adults and the risk of rheumatic fever is low 3.

Over-the-counter rapid strep tests have become available at pharmacies and are convenient, but clinical guidelines recommend that a negative home test result in a child be confirmed with a culture in a medical setting 3. The sensitivity of point-of-care rapid tests varies considerably depending on who performs the swab and which test kit is used 2.

Treatment

Viral sore throat: No antibiotic is effective or appropriate. Symptoms typically peak in the first 2–3 days and resolve on their own; 85% of people are symptom-free within one week regardless of the cause 1. Supportive care — rest, adequate fluids, salt-water gargles, and over-the-counter pain relievers — addresses discomfort during recovery.

Confirmed strep throat: Antibiotics shorten symptom duration by roughly one day and, importantly, reduce the risk of complications including rheumatic fever [2, 3]. First-line treatment per CDC and IDSA guidelines is penicillin or amoxicillin for 10 days 3. For individuals with a penicillin allergy, alternatives include cephalexin, cefadroxil, clindamycin, azithromycin, or clarithromycin 3. Starting antibiotics within 48 hours of symptom onset produces the most benefit.

After 12–24 hours on effective antibiotics and once fever has resolved, most people with strep are no longer contagious and can return to school or work 3.

Broad-spectrum or newer antibiotics offer no advantage over penicillin for strep throat and are not recommended as first-line therapy 2.

Complications to Know About

Left untreated, Group A strep can lead to complications that range from local to systemic:

  • Peritonsillar abscess: Pus collecting around the tonsil, causing severe one-sided throat pain, a muffled voice, and difficulty opening the mouth. Requires drainage and is a reason to seek urgent in-person care.
  • Acute rheumatic fever: An inflammatory condition that can damage heart valves. In the United States, rheumatic fever is rare — about 0.5 cases per 100,000 — primarily because strep infections are commonly treated with antibiotics 2. The risk is significantly higher in untreated children.
  • Post-streptococcal glomerulonephritis: Inflammation of the kidneys, which can present as dark or foamy urine after a strep infection.
  • Scarlet fever: A strep infection accompanied by a characteristic red, sandpaper-like rash. Treated with the same antibiotics used for strep throat 3.

Viral sore throats do not carry these risks, which reinforces the importance of accurate diagnosis before prescribing antibiotics 1.

Antibiotic Overprescribing: A Real Problem

Despite strep accounting for only 5–15% of adult sore throat cases, studies estimate that 47–75% of adults who visit a clinician for a sore throat receive an antibiotic prescription 2. This gap represents one of the clearest examples of antibiotic overprescribing in primary care.

The CDC and IDSA both recommend testing — not empiric prescribing — for most patients with sore throat symptoms [3, 4]. Clinical scoring tools like the Modified Centor score help identify which patients are low enough risk that testing is unnecessary, and which warrant a swab before any antibiotic is considered 4.

When a Telehealth Visit Works — and When It Doesn't

Many sore throat evaluations can be completed via video visit. A clinician can assess throat appearance with good lighting, score symptoms using the Modified Centor criteria, and — in lower-probability cases — confirm that watchful waiting is appropriate 4.

For situations where a rapid strep test is warranted but in-person care is not immediately accessible, some telehealth platforms arrange same-day testing at a partner pharmacy or urgent care lab before the virtual visit. For adults with moderate-to-high Centor scores, a prescription after a confirmed positive test can be sent electronically to a local pharmacy.

In-person evaluation remains the better choice when there is concern about peritonsillar abscess (severe one-sided pain, voice change, difficulty swallowing), breathing difficulty, drooling, or inability to open the mouth — all of which require physical examination.

Common questions

How can I tell if my sore throat is strep or a cold without going to the doctor?

No symptom combination can definitively rule strep in or out without a test. That said, strep is more likely when throat pain comes on suddenly and is severe, there is fever, the lymph nodes in the neck are swollen and tender, and there is no cough. A sore throat accompanied by a runny nose, cough, hoarseness, or pink eye is more likely viral. If symptoms suggest strep — especially in a child — a rapid strep test confirms or rules it out quickly.

Do I need antibiotics for a sore throat?

Only if the cause is confirmed bacterial (most often Group A strep). Viral sore throats — the majority of cases — do not benefit from antibiotics, and using them unnecessarily contributes to antibiotic resistance. A positive rapid strep test or throat culture is the basis for prescribing antibiotics in most cases.

How long does strep throat last without treatment?

Strep throat, like most viral sore throats, tends to resolve on its own within one week even without antibiotics. However, antibiotics shorten the illness by roughly a day and — critically — reduce the risk of complications such as rheumatic fever and peritonsillar abscess. Treatment also makes the person non-contagious faster.

Can I get strep throat if I've had my tonsils removed?

Yes. Tonsillectomy reduces the frequency of recurrent strep infections in children who qualify for the procedure, but it does not eliminate the pharynx as a site of Group A strep infection. People without tonsils can still contract and spread strep.

What is the Modified Centor score and does my doctor actually use it?

The Modified Centor (McIsaac) score assigns points for fever, swollen lymph nodes, tonsillar exudate, no cough, and younger age. A score of 4 corresponds to roughly a 57% probability of strep. Both the CDC and IDSA recommend clinicians use this or a similar scoring tool to decide whether to test, treat empirically, or reassure. In practice, use varies, but many emergency department and primary care clinicians apply it, especially in telemedicine settings.

Can strep throat spread without symptoms?

Yes. Group A strep can be carried in the throat without causing symptoms. Asymptomatic carriers are generally much less contagious than people with active infection, and treatment of carriers is not routinely recommended unless there are outbreak circumstances or a high-risk household contact.

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When to seek care

  • —Difficulty breathing or breathing that sounds noisy or labored
  • —Drooling, inability to swallow, or refusing to drink fluids
  • —Muffled or 'hot-potato' voice with severe one-sided throat pain (possible peritonsillar abscess)
  • —Stiff neck or difficulty opening the mouth fully
  • —Rash appearing alongside sore throat (possible scarlet fever — needs antibiotic treatment)
  • —Sore throat persisting beyond 10 days without improvement
  • —Recurrence of fever after several days of improvement
  • —Swelling of the face or neck, or difficulty breathing while swallowing
  • —Signs of dehydration in a child: no tears when crying, no urination in 8+ hours, dry mouth

Call 911 or go to the nearest emergency room immediately for difficulty breathing, severe drooling with inability to swallow, or rapid swelling of the throat.

General health information, not medical advice. Synthetic demonstration content.

References

  1. 1.Spinks A, Glasziou PP, Del Mar CB (2021). Antibiotics for treatment of sore throat in children and adults. Cochrane Database of Systematic Reviews. doi:10.1002/14651858.CD000023.pub5 ✓Most sore throats are viral; 85% resolve by one week regardless of cause; viral causes include rhinovirus, coronavirus, RSV, and Epstein-Barr; mono accounts for ~2% of adult pharyngitis
  2. 2.Matthys J, De Meyere M, van Driel ML, et al. (2020). Diagnostic Methods, Clinical Guidelines, and Antibiotic Treatment for Group A Streptococcal Pharyngitis: A Narrative Review. International Journal of General Medicine (PMC7593338). doi:10.2147/IJGM.S260037 ✓Strep causes 5–15% of adult sore throats and 15–35% of pediatric cases; RADT sensitivity ~85%, specificity ~96%; antibiotics shorten illness by ~1 day; antibiotic overprescribing affects 47–75% of adults; broad-spectrum antibiotics offer no advantage over penicillin
  3. 3.Centers for Disease Control and Prevention (2024). Clinical Guidance for Group A Streptococcal Pharyngitis. CDC Group A Strep Clinical Guidance. link ✓Penicillin/amoxicillin first-line for 10 days; negative RADT in children requires throat culture follow-up; return to school after 12–24 hours on antibiotics; suppurative and nonsuppurative complications of untreated strep; antibiotics not indicated for viral sore throat
  4. 4.Infectious Diseases Society of America (2025). IDSA Clinical Practice Guideline Update on Group A Streptococcal (GAS) Pharyngitis. IDSA Practice Guidelines. link ✓Modified Centor (McIsaac) score recommended to guide testing decisions; Centor score 4 = 57% strep probability; McIsaac score 4–5 = 50.7–69.3% probability; low-score patients do not need testing
  5. 5.Harris AM, Hicks LA, Qaseem A; High Value Care Task Force of the American College of Physicians and CDC (2022). Streptococcal Pharyngitis — StatPearls. StatPearls, NCBI Bookshelf (NBK525997). link ✓Strep incidence 93 cases per 1,000 in children aged 3–9; only 1.1 per 1,000 in adults 40–65; rheumatic fever 0.5 per 100,000 in the US; suppurative complications in ~1% of untreated cases; broad-spectrum antibiotics do not reduce treatment failure
  6. 6.Centers for Disease Control and Prevention (2024). Testing for Strep Throat or Scarlet Fever. CDC Group A Strep — Testing. link ✓Throat culture is gold standard; negative RADT in children/teens warrants culture; adults do not routinely need backup culture after negative RADT; positive test warrants antibiotic prescription

https://www.gale.care/conditions/sore-throat · 6 sources. General health information, not medical advice — synthetic demonstration content.