When your throat hurts, the obvious question is whether you need antibiotics for a sore throat. The honest answer — backed by the Infectious Diseases Society of America (IDSA) Group A Strep guidelines — is usually "no." Roughly 70–90% of adult sore throats are viral and resolve on their own. The remaining 10–30% are caused by Group A Streptococcus and benefit from antibiotic therapy. Getting this distinction right matters for your recovery and for antibiotic stewardship.

The Centor criteria, simplified

Clinicians use the Centor criteria with the McIsaac age modifier to estimate strep probability before any test. Four criteria, each worth one point: fever ≥38°C, absence of cough, tender anterior cervical lymphadenopathy, and tonsillar exudate (white spots on the tonsils). The age modifier: ages 3–14 add +1, ages 15–44 add 0, ages 45+ subtract 1. Maximum score is 5; minimum is −1.

Score 0–1 (very low probability)

Strep is unlikely. Neither testing nor antibiotics are appropriate. Treat symptoms with rest, fluids, acetaminophen or ibuprofen, throat lozenges, and warm salt-water gargles.

Score 2–3 (moderate probability)

Test before treating. This is where rapid strep antigen tests or throat culture matter most — empiric antibiotic prescribing at this score range over-treats viral cases. Home rapid strep tests and in-person urgent care tests both work.

Score 4–5 (high probability)

With the classic picture (sudden onset, fever, no cough, swollen glands, white spots), empiric antibiotic treatment can be reasonable per IDSA guidance — especially when getting a test would significantly delay care. A licensed doctor can make this call.

Why antibiotic stewardship matters

Antibiotics taken for viral pharyngitis have downsides: personal side effects (diarrhea, rash, yeast infection, rare but serious C. difficile colitis), microbiome disruption that can last months, and antibiotic resistance. The CDC Antibiotic Resistance Threats Report lists resistance as a top public health threat. Every unnecessary prescription contributes.

How CodyMD applies this clinically

When you text Cody about a sore throat, a licensed physician walks through Centor/McIsaac with you. If you score 4–5 with classic features, antibiotics may be sent to your pharmacy in 1 hour. If you score 2–3, the doctor recommends a home rapid strep test or in-person swab before any prescription — antibiotic stewardship in practice. For more on the visit, see online strep throat treatment, and for what gets prescribed see strep throat antibiotics.

What to do for viral sore throat

Supportive care: acetaminophen or ibuprofen for pain and fever, warm fluids and broths, throat lozenges (anesthetic varieties for severe pain), salt-water gargles (1/4 tsp salt in 8 oz warm water), humidified air, and rest. Viral pharyngitis typically resolves in 3–10 days.

When to escalate

Regardless of strep status, seek urgent in-person care if you can't swallow saliva, have difficulty breathing, develop a muffled "hot potato" voice, can't open your mouth fully, or develop a stiff neck with severe headache. These can signal complications. See strep throat symptoms for the full red-flag list.

Bottom line

Most sore throats are viral and don't need antibiotics. Centor/McIsaac scoring is the clinical tool for sorting strep from viral. A licensed CodyMD doctor applies it in minutes — and if you have strep, antibiotics are at your pharmacy in 1 hour.