About Pharyngitis (Sore Throat)
Pharyngitis can be caused by viral infections, bacterial infections, allergies, irritants, reflux, or dryness. Viruses are the most common cause and include rhinovirus, coronavirus, adenovirus, influenza, parainfluenza, Epstein-Barr virus, and SARS-CoV-2. These infections can spread through respiratory droplets, saliva, nasal secretions, and close contact. Group A Streptococcus is the most important bacterial cause of acute pharyngitis and is responsible for about 20% to 30% of sore throats in children and 5% to 15% in adults. Other less common bacterial causes include group C and group G Streptococcus, Fusobacterium necrophorum in some adolescents and young adults, Mycoplasma pneumoniae, chlamydia, and gonorrhea.
Risk factors that can increase the chance of infectious pharyngitis include:
- Age: Strep throat is most common in children 5 to 15 years old and is uncommon in children younger than 3 years.
- Close contact: Living with or spending time near someone who has a respiratory infection or strep throat increases risk.
- Crowded settings: Schools, childcare centers, dormitories, shelters, and similar settings can make infections easier to spread.
- Season: Strep throat is more common in winter and early spring in many areas.
Other factors can irritate the throat or make symptoms more likely, including:
- Not taking infection-prevention steps: Handwashing, covering coughs and sneezes, and avoiding close contact with people who are sick can lower the chance of infection.
- Smoking or exposure to secondhand smoke: Smoke can irritate the throat and worsen symptoms.
- Allergies or postnasal drip: Drainage from the nose or sinuses can irritate the throat.
- Dry air, voice strain, or acid reflux: These can cause or worsen throat irritation even when infection is not present.
Having one or more risk factors does not mean a person will develop pharyngitis. Good hand hygiene, avoiding shared cups or utensils, staying home when sick, and reducing exposure to smoke and other irritants can help lower risk.
Pharyngitis usually causes a sore, scratchy, or dry throat and may cause pain with swallowing. Symptoms that often occur with viral infections include:
- Cough
- Headache
- Runny nose
- Eye irritation
- Swollen tonsils
- Postnasal drip
- Swollen lymph node
- Fatigue
- Fever
Features that may suggest strep throat include a sudden sore throat, fever, pain with swallowing, swollen and tender lymph nodes in the front of the neck, red or swollen tonsils, tonsillar exudate, and no cough. Strep throat can also cause headache, nausea, vomiting, abdominal pain, or a sandpapery rash called scarlet fever, especially in children.
Some symptoms may suggest a more serious condition or a complication and should prompt medical care. These include:
- Difficulty breathing, drooling, or inability to swallow fluids
- Severe one-sided throat pain, swelling, muffled voice, or trouble opening the mouth
- Fever of 103°F (39.4°C) or higher, or fever that persists
- Sore throat lasting longer than about a week or symptoms that worsen after initially improving
- Blood in saliva or phlegm, signs of dehydration, or a widespread rash
- Overwhelming fatigue, enlarged lymph nodes, or upper-left abdominal pain, which may occur with mononucleosis
To diagnose pharyngitis, a healthcare professional typically reviews symptoms and examines the throat, tonsils, nose, ears, neck, and breathing. If symptoms clearly suggest a viral infection, such as cough, runny nose, hoarseness, oral ulcers, or conjunctivitis, testing for strep throat usually is not needed. If strep throat is suspected, diagnosis should be confirmed with a rapid antigen detection test, nucleic acid amplification test, or throat culture before antibiotics are used.
In addition to these common examinations and tests, there are other approaches that can be used to determine the severity of pharyngitis:
- Clinical decision tools: Tools such as the Centor or McIsaac criteria can help estimate the likelihood of strep throat based on fever, tonsillar exudate or swelling, tender anterior cervical lymph nodes, absence of cough, and age. These tools help decide who needs testing; they do not replace testing when antibiotics are being considered.
- Rapid antigen detection tests: These can identify group A strep quickly. In children and adolescents, a negative rapid antigen test is often backed up with a throat culture because rapid tests can miss some cases.
- Throat culture or nucleic acid amplification testing: These tests can confirm group A strep. A throat culture may take 24 to 48 hours, while nucleic acid tests may provide faster results when available.
- Other testing: Testing for COVID-19, flu, mononucleosis, gonorrhea, or other causes may be considered based on symptoms, exposure history, sexual history, age, and local circulation of infections.
It is important to note that the choice of examinations, tests, and procedures may vary depending on the healthcare setting and available resources. Additionally, healthcare professionals should consider factors such as the patient's medical history, risk factors, and local guidelines when determining the appropriate diagnostic approach for pharyngitis.
Treatment for pharyngitis depends on the cause. The goals are to relieve symptoms, reduce spread when an infection is contagious, and prevent complications when strep throat is confirmed.
- Medications:
- Antibiotics: Antibiotics are used for confirmed or strongly suspected bacterial pharyngitis, especially group A strep. Penicillin or amoxicillin are common first-line options. Alternatives may be used for people with penicillin allergy, but local resistance patterns matter for macrolide antibiotics such as azithromycin or clarithromycin. Antibiotics are not helpful for viral pharyngitis.
- Over-the-counter pain relievers: Acetaminophen or ibuprofen can help reduce throat pain and fever. Aspirin should not be given to children or teenagers because of the risk of Reye syndrome.
- Corticosteroids: Steroids are not routinely recommended for uncomplicated sore throat and should only be used if a healthcare professional determines they are appropriate.
- Self-care and health behavior changes:
- Saltwater gargles: Gargling with warm salt water can help ease throat pain and reduce inflammation. The saltwater helps to draw out excess fluid from the throat tissues, reducing swelling and discomfort.
- Rest: Getting plenty of rest allows your body to recover and fight off the infection more effectively.
- Hydration: Staying hydrated by drinking plenty of fluids helps soothe the throat and prevents dehydration.
- Humidifier use: Using a humidifier adds moisture to the air, which can help alleviate dryness in the throat.
- Throat lozenges: Sucking on throat lozenges can provide temporary relief by soothing the throat and reducing irritation.
- Warm beverages: Drinking warm liquids like tea with honey, lemon water, or broth can help soothe the throat.
Most sore throats are viral and improve without antibiotics. Symptom-focused care may include rest, fluids, warm saltwater gargles, honey for people older than 1 year, throat lozenges or hard candy for people who can use them safely, and humidified air. People with contagious infections should avoid close contact with others when possible and follow public health or clinician guidance about returning to school, work, or childcare.
If antibiotics are prescribed, take them exactly as directed and complete the full course unless a healthcare professional advises otherwise. A person should seek reevaluation if symptoms worsen, do not begin to improve after 48 to 72 hours of antibiotic treatment, or last longer than expected. Medication dosing and side effects can vary, so people should follow their clinician’s instructions and read the information provided with the medication.
Pharyngitis typically follows a natural progression and can have different outcomes depending on its cause.
Natural progression:
- Pharyngitis is often a symptom of colds or the flu and is usually caused by a viral infection.
- Viral pharyngitis tends to clear up on its own within a couple of weeks without any specific treatment.
- Bacterial pharyngitis, on the other hand, may require antibiotics to prevent complications.
- It's important to note that pharyngitis can be caused by different types of bacteria, but one common culprit is Streptococcus pyogenes (Group A Streptococcus or GAS).
Complications of pharyngitis are rare but can occur. Rarely, bacterial pharyngitis, especially if caused by GAS, can lead to complications such as peritonsillar abscess, rheumatic fever, acute streptococcal glomerulonephritis, scarlet fever, arthritis, and toxic shock syndrome.
- Peritonsillar abscess is a collection of pus near the tonsil that can cause severe one-sided throat pain, muffled voice, drooling, fever, and trouble opening the mouth.
- Acute rheumatic fever is an immune-mediated condition that can affect the heart, joints, skin, and nervous system after untreated or inadequately treated group A strep infection.
- Post-streptococcal glomerulonephritis is an immune-mediated kidney condition that can occur after some strep infections.
- Scarlet fever is strep throat with a characteristic sandpapery rash and requires treatment for the underlying group A strep infection.
- Invasive group A strep infections and streptococcal toxic shock syndrome are rare but serious complications that need urgent medical care.
Most cases of pharyngitis improve without complications. Medical care is important when symptoms are severe, persistent, recurrent, or suggest strep throat or another treatable infection. Prompt diagnosis and appropriate treatment can help relieve symptoms, reduce transmission, and lower the risk of some complications.