Pharyngitis (Sore Throat)

Causes of pharyngitis

Viral (most common)

• common cold viruses (rhinovirus, coronavirus, adenovirus)
• influenza and COVID-19
• infectious mononucleosis (Epstein-Barr virus): severe sore throat, tonsil exudate, swollen glands, extreme tiredness, often in teens and young adults
• hand, foot and mouth disease and herpangina (coxsackievirus) in young children, with mouth blisters
• acute HIV infection, rarely

Bacterial

• Group A streptococcus (strep throat): causes about 20 to 30% of sore throats in children and 5 to 15% in adults
• groups C and G streptococcus
• Fusobacterium necrophorum in teens and young adults, rarely leading to Lemierre syndrome
• gonorrhea and, rarely, diphtheria in unvaccinated people

Non-infectious

• acid reflux (laryngopharyngeal reflux)
• postnasal drip from allergies or sinusitis
• dry air, smoking, shouting and pollution
• rarely, throat cancer, especially with persistent one-sided pain in smokers

Viral vs strep throat

The Centor (McIsaac) score adds points for fever, tonsil exudate, swollen tender front neck glands, absence of cough and age under 15, and subtracts for age over 45. Higher scores mean testing is more worthwhile.

Symptoms

• sore throat, worse on swallowing
• scratchy, dry or raw throat
• fever, headache and body aches
• swollen neck glands
• red, swollen tonsils, sometimes with white patches
• hoarse voice, cough and runny nose (viral)
• nausea, vomiting and abdominal pain, especially in children with strep

Diagnosis

• examination of the throat, neck and ears
• rapid antigen detection test for strep, results in minutes
• throat culture if the rapid test is negative in children and teens, because of the risk of rheumatic fever
• monospot or EBV antibodies for suspected mono
• COVID-19 or flu tests when relevant

Testing for strep is not recommended for people with clear viral features, and children under 3 rarely need testing.

Treatment

Home care for all sore throats

• acetaminophen (paracetamol) or ibuprofen for pain and fever. Follow the label dose. Do not give aspirin to children or teenagers
• warm drinks, honey (not for babies under 12 months), cold drinks and ice pops
• throat lozenges and anesthetic sprays for older children and adults
• salt water gargles: about 1/2 teaspoon of salt in 8 oz (240 ml) of warm water
• rest and plenty of fluids
• a humidifier

Antibiotics for strep throat

• penicillin V or amoxicillin for 10 days are first choice
• alternatives for penicillin allergy include cephalexin, azithromycin or clindamycin
• antibiotics shorten symptoms by about a day, reduce spread and prevent complications such as rheumatic fever and peritonsillar abscess
• people are no longer contagious after 12 to 24 hours of antibiotics

Antibiotics do not help viral pharyngitis and cause side effects. In mono, amoxicillin often causes a rash.

Steroids

A single dose of steroid may be used in adults with severe pain, under medical advice.

Complications

Of strep throat

• peritonsillar abscess (quinsy)
• scarlet fever
• ear infection and sinusitis
• rheumatic fever, which can damage heart valves, now rare in the US
• post-streptococcal glomerulonephritis (kidney inflammation)
• Sydenham's chorea

Of mono

• enlarged spleen, with a risk of rupture, so contact sports are avoided for at least 3 to 4 weeks
• airway swelling, rarely

How long does pharyngitis last?

Viral sore throats usually improve within 3 to 7 days and resolve within 10 days. Strep throat improves within 1 to 2 days of antibiotics. Mono can cause sore throat for 1 to 2 weeks and fatigue for weeks to months.

Prevention

Wash hands, avoid sharing cups and utensils, cover coughs, and replace toothbrushes after strep. Keep up with flu and COVID-19 vaccines. Children with strep should stay home until at least 12 hours after starting antibiotics and fever has resolved.

Frequently asked questions

Is pharyngitis viral or bacterial?

Most pharyngitis is viral, particularly in adults. Group A strep causes about a quarter of sore throats in school-age children and a smaller share in adults. A rapid strep test or throat culture tells them apart when symptoms suggest strep.

How do I know if my sore throat is strep?

Strep is more likely with sudden sore throat, fever, swollen tender neck glands, white patches on the tonsils and no cough or runny nose, especially in children aged 5 to 15. Only a strep test can confirm it.

How long does pharyngitis last?

Viral pharyngitis usually lasts 3 to 7 days and is gone within 10 days. Strep throat improves within a day or two of starting antibiotics. See a doctor if a sore throat lasts more than a week or keeps returning.

What is the fastest way to cure a sore throat?

There is no instant cure for viral sore throats, but pain relievers, warm or cold drinks, honey, lozenges and salt water gargles ease symptoms while your body clears the virus. Antibiotics speed recovery only for strep throat.

Is pharyngitis contagious?

Yes. Both viral and strep pharyngitis spread through droplets and shared items. People with strep are no longer contagious after about 12 to 24 hours of antibiotics. Viral sore throats are contagious while other cold symptoms are present.