Sore Throat — Causes, Strep vs Viral & When to See a Doctor — Causes, Diagnosis & When to See a Doctor | MyMedicPlus

Sore throat (pharyngitis or tonsillopharyngitis) is characterised by pain, scratchiness, rawness, or irritation in the throat, typically worsening with swallowing and sometimes with breathing. It is one of the most frequent reasons for primary care visits worldwide, accounting for millions of consultations and antibiotic prescriptions annually. Sore throats are most common in children aged 5-15 and in adults with frequent close contact with children or in crowded environments such as universities and military barracks. The critical clinical skill lies in distinguishing viral pharyngitis — which requires only supportive care and no antibiotics — from Group A Streptococcal (GAS) pharyngitis, which requires antibiotic treatment to eradicate the bacterium and prevent serious complications including peritonsillar abscess and rheumatic fever with permanent cardiac valve damage. Importantly, overconsumption of antibiotics for viral sore throats drives antimicrobial resistance — one of the most significant global health threats — making accurate diagnosis and antimicrobial stewardship essential in everyday clinical practice.

Viral causes account for 70-80% of sore throats and include adenovirus (most common viral cause — pharyngitis with conjunctivitis is characteristic), rhinovirus (common cold — usually milder pharyngitis with runny nose), influenza (severe pharyngitis with fever, myalgia, and systemic illness), Epstein-Barr virus (infectious mononucleosis/glandular fever — classically causes severe exudative pharyngitis with marked fatigue, cervical lymphadenopathy, and splenomegaly), and Coxsackievirus (herpangina — vesicular ulcers on the palate and tonsils in children; hand-foot-mouth disease). Bacterial causes include Group A Streptococcus — Streptococcus pyogenes — the only common bacterial cause warranting antibiotic treatment, accounting for 15-30% of cases in children and 5-15% in adults. Less common bacterial causes include Group C and G Streptococcus, Fusobacterium necrophorum (associated with Lemmiere's syndrome), and Mycoplasma pneumoniae. Non-infectious causes include post-nasal drip from allergic rhinitis or sinusitis (chronic morning sore throat, throat clearing), gastro-oesophageal reflux disease (GERD — morning sore throat with heartburn), dry air exposure, smoking or passive smoke exposure, and vocal overuse or strain. Serious causes requiring urgent assessment include epiglottitis (rapidly progressive swelling of the epiglottis — airway emergency), peritonsillar abscess (collection of pus beside tonsil — requires drainage), and retropharyngeal abscess.

Seek emergency care immediately for sore throat with drooling or inability to swallow saliva — this suggests epiglottitis (life-threatening swelling of the epiglottis from bacterial infection, typically Haemophilus influenzae type b or Group A Streptococcus) or peritonsillar abscess with impending airway compromise. Call emergency services for stridor — a high-pitched crowing sound on inspiration — which indicates critical upper airway narrowing. Also seek emergency assessment for muffled 'hot potato' voice, trismus (difficulty opening the mouth), and unilateral tonsillar swelling with uvular deviation toward the unaffected side — these are hallmarks of peritonsillar abscess requiring same-day incision and drainage or aspiration. Seek urgent assessment for sore throat with high fever above 39°C that does not respond to paracetamol, sore throat with severe neck stiffness and headache (possible meningitis or retropharyngeal abscess), bilateral tonsil enlargement to the point of meeting in the midline (possible airway risk from severe mononucleosis), difficulty breathing with a sore throat at any age, or sore throat lasting more than two to three weeks without clear diagnosis — this requires examination to exclude laryngeal or pharyngeal malignancy, particularly in adults over 45 with smoking or alcohol history.

Clinical examination assesses tonsillar size (graded 1+ to 4+ using Brodsky grading), erythema and inflammation of the posterior pharynx, presence of tonsillar exudate (white or yellow pus), petechiae on the soft palate (strongly suggests Group A Streptococcal infection), and anterior cervical lymphadenopathy with tenderness. The Centor or McIsaac scoring system quantifies clinical probability of GAS pharyngitis, adding one point each for: tonsillar exudate, swollen tender anterior cervical lymph nodes, fever above 38°C, and absence of cough; one point is deducted for age over 45 years. A score of 4 or more has a positive predictive value of approximately 56% for GAS and warrants antibiotic treatment without testing. A rapid antigen detection test (RADT) for Group A Streptococcus provides results in 5-10 minutes at the point of care, with high specificity (95-99%) but moderate sensitivity (70-90%). Throat culture remains the gold standard for GAS with near-100% sensitivity when performed correctly; results take 24-48 hours. Monospot (heterophile antibody) test and Epstein-Barr virus serology (VCA-IgM) diagnose infectious mononucleosis. Blood count demonstrates lymphocytosis with atypical lymphocytes (mononucleosis) or neutrophilia (bacterial infection). Ultrasound or CT of the neck delineates peritonsillar or retropharyngeal abscess extent.

Viral sore throat management focuses on symptom relief: rest, adequate oral hydration with warm fluids (warm water with honey and lemon, warm broth), warm salt water gargles (one teaspoon of salt in 240 mL warm water, four to six times daily), and systemic analgesia with paracetamol (1 g four times daily) or ibuprofen (400 mg three times daily with food) to reduce fever and throat pain. Throat lozenges containing benzocaine, flurbiprofen, or amylmetacresol provide additional local anaesthetic relief. Honey taken directly has modest evidence for soothing throat irritation in adults (avoid honey in children under one year). Throat sprays with antiseptic agents provide temporary comfort. Group A Streptococcal pharyngitis requires a full ten-day course of penicillin V (phenoxymethylpenicillin) or amoxicillin — the latter preferred for children as it is available as a palatable suspension. Azithromycin or clarithromycin for five days is used in confirmed penicillin allergy. Completing the full antibiotic course is essential to eradicate GAS and prevent development of peritonsillar abscess and rheumatic fever. A single dose of oral dexamethasone (10 mg in adults) significantly reduces the duration and severity of throat pain in severe pharyngitis, including strep throat. Peritonsillar abscess requires same-day aspiration or incision and drainage under local anaesthetic, plus oral antibiotics (co-amoxiclav) for five to seven days.

Practise thorough and frequent handwashing with soap and water — particularly during autumn and winter respiratory virus seasons — before eating and after blowing your nose, coughing, or touching shared surfaces. Group A Streptococcus is highly contagious by direct contact and respiratory droplets; infected individuals should stay home from school, childcare, or work for at least 24 hours after initiating antibiotic therapy, after which contagiousness ceases rapidly. Do not share drinking vessels, eating utensils, or toothbrushes — GAS survives on these surfaces. Annual influenza vaccination significantly reduces the incidence of influenza pharyngitis and associated complications. Stay well hydrated to maintain mucosal integrity and immune function. Avoid direct contact with known mononucleosis cases — Epstein-Barr virus is transmitted via saliva ('kissing disease'). Avoid smoking and secondhand smoke exposure, which directly irritates and inflames pharyngeal and tonsillar mucosa, impairs mucociliary clearance, and increases susceptibility to bacterial superinfection. Manage allergic rhinitis and GERD promptly as both cause recurrent pharyngeal irritation mimicking sore throat.

Seek emergency care immediately for sore throat with drooling or inability to swallow saliva, stridor (high-pitched noisy breathing), asymmetric tonsillar swelling with uvular deviation, or difficulty opening the mouth — these are airway emergencies. Call emergency services for any child or adult with breathing difficulty from throat swelling. Seek same-day urgent assessment for sore throat with fever above 39°C not responding to paracetamol after 24 hours, suspicion of peritonsillar abscess (one-sided tonsil swelling, muffled voice, severe pain on swallowing), sore throat with neck stiffness and severe headache, or swallowing difficulty with drooling at any age. Arrange an urgent same-day or next-day appointment for sore throat with fever, exudate, and enlarged neck lymph nodes suggesting strep throat — antibiotic initiation reduces symptom duration and prevents complications. See a doctor within one to two days for children with sore throat and fever, as strep throat carries significant complication risk in children including rheumatic fever. Seek a routine appointment for sore throats recurring frequently (five or more times per year) — tonsillectomy may be appropriate. Any sore throat persisting beyond three weeks in an adult over 40 with smoking or heavy alcohol history requires urgent ENT assessment to exclude laryngeal or oropharyngeal cancer.