Pharyngitis: Causes, Symptoms, and Treatment

Pharyngitis is the medical term for inflammation of the throat (pharynx) and is one of the most common reasons people visit a doctor for a sore throat. It usually causes pain, discomfort, and difficulty swallowing. The condition can be short-term (acute), lasting less than three weeks, or long-term (chronic) if symptoms continue beyond that.

Most cases are caused by viruses, such as those responsible for the common cold and flu. Bacterial infections, especially Streptococcus pyogenes (strep throat), are less common but often more severe. Pharyngitis can also occur without infection, triggered by allergies, air pollution, cigarette smoke, or dry air.

This condition affects people of all ages but is especially common in school-aged children. In the United States, more than 11 million medical visits each year are linked to sore throats. Viral infections make up the majority of cases, around 70–90% in adults and 60–70% in children, while bacterial infections account for 5–15% of adult cases and 20–30% in children. Most viral cases are mild and get better on their own.

Prevention focuses on reducing exposure to germs and irritants. Recommended measures include washing hands regularly, avoiding close contact with sick individuals, keeping indoor air clean and moist, and limiting exposure to tobacco smoke and allergens.

Treatment depends on the cause: viral pharyngitis is usually treated with rest, fluids, warm salt-water gargles, and pain relievers such as acetaminophen or ibuprofen. Bacterial pharyngitis is treated with antibiotics, with penicillin and amoxicillin being the most commonly prescribed, while macrolides (such as azithromycin or clarithromycin) are used for people allergic to penicillin.

Pharyngitis Versus Other Throat Infections

Pharyngitis specifically refers to inflammation of the pharynx, the part of the throat located behind the mouth and nasal cavity. This makes it different from related conditions that also affect structures in the throat. Although these disorders may present with similar symptoms, each involves a different anatomical region and therefore may require different treatment approaches.

Tonsillitis, for example, is inflammation of the tonsils, which are soft tissue glands located on both sides at the back of the throat. The tonsils are technically part of the pharynx, but tonsillitis is more localized and typically causes visibly swollen or infected tonsils, sometimes with white patches (exudates). Tonsillitis often leads to more prominent pain when swallowing and may be accompanied by swollen lymph nodes in the neck. Many cases of pharyngitis include tonsillar involvement, but tonsillitis on its own refers specifically to inflammation of the tonsils rather than the entire throat.

Laryngitis, on the other hand, involves inflammation of the larynx, also known as the voice box, which sits below the pharynx. Because the larynx contains the vocal cords, the most noticeable symptom of laryngitis is hoarseness or complete loss of voice. This symptom is far less common in pharyngitis, which mainly causes throat pain rather than voice changes. Laryngitis is often associated with overuse of the voice, viral infections, or irritation from smoke or acid reflux.

A closely related but far more serious condition is epiglottitis, which is inflammation or infection of the epiglottis, a small flap of tissue that protects the airway during swallowing. Unlike pharyngitis, epiglottitis can rapidly become life-threatening because the swelling can block airflow into the lungs. It typically presents with severe sore throat, high fever, drooling (due to difficulty swallowing), and breathing problems. Immediate medical treatment is essential, often in a hospital setting, to prevent airway obstruction. Epiglottitis is now less common in children due to routine vaccination against Haemophilus influenzae type b (Hib), one of its most common bacterial causes.

Causes of Pharyngitis

Viral Causes

Viruses are the most common cause of pharyngitis, accounting for the majority of cases in both children and adults. Several different respiratory viruses are capable of infecting the throat, including rhinovirus (the most frequent cause of the common cold), adenovirus (which also causes conjunctivitis and flu-like symptoms), and influenza virus. Another important viral cause is the Epstein–Barr virus (EBV), which is responsible for infectious mononucleosis, sometimes called “mono” or “the kissing disease.” EBV-related pharyngitis tends to be more prolonged and may be accompanied by extreme fatigue, swollen tonsils, and enlarged lymph nodes.

Viral infections cause inflammation by invading the mucous membranes that line the throat. These infections are typically spread through respiratory droplets, which are released when an infected person coughs, sneezes, or talks, as well as through direct contact with contaminated surfaces such as door handles and shared utensils. Because the viruses are highly contagious, crowded environments, schools, public transportation, and households, are common settings for transmission.

Bacterial Causes

Bacterial pharyngitis is less common than viral pharyngitis but is typically more severe. The leading bacterial cause is Group A Streptococcus (GAS), also known as Streptococcus pyogenes, which causes strep throat. Strep throat often presents with a sudden onset of severe throat pain, high fever, swollen lymph nodes in the neck, and sometimes white patches or pus on the tonsils. Unlike viral infections, strep throat rarely causes coughing or a runny nose, which can help distinguish it clinically.

Although GAS is the most frequent bacterial pathogen, other bacteria can also lead to pharyngitis, including Mycoplasma pneumoniae and Chlamydia pneumoniae, which more commonly affect adolescents and young adults. These bacteria are often associated with milder or atypical respiratory infections.

Bacterial causes require antibiotic treatment, not only to shorten the duration of illness but also to prevent potentially serious complications, such as rheumatic fever, which can damage the heart, and post-streptococcal glomerulonephritis, a kidney disorder.

Non-Infectious Causes

Not all pharyngitis is caused by infection. In many individuals, throat inflammation results from irritation or physical injury rather than a virus or bacteria. Airborne irritants such as cigarette smoke, industrial pollution, chemical fumes, or dry indoor air can inflame the throat lining, especially in people with underlying respiratory sensitivity. Seasonal or environmental allergens, including pollen, dust mites, and pet dander, can also trigger inflammation in susceptible individuals by causing chronic postnasal drip and throat irritation.

Mechanical strain plays a role as well. Excessive yelling, singing, persistent coughing, or frequent throat clearing can overwork or inflame the delicate tissues of the pharynx, leading to irritation that mimics symptoms of infectious pharyngitis. Another important non-infectious cause is gastroesophageal reflux disease (GERD), in which stomach acid travels upward into the throat, irritating the mucosal lining, particularly at night or when lying down.

Unlike infectious forms, non-infectious pharyngitis does not involve the spread of germs and is not contagious. Symptoms usually improve once the underlying irritant is removed or managed.

Symptoms of Pharyngitis

Pharyngitis presents with specific signs that can vary between children and adults. Understanding these symptoms helps distinguish mild cases from those requiring urgent care.

Common Signs

Pharyngitis typically causes a sore throat characterized by pain or discomfort when swallowing. The throat may appear red and swollen.

Other common symptoms include:

Fever
Headache
Fatigue
Swollen lymph nodes in the neck
Hoarseness or loss of voice

Some cases produce white patches or pus on the tonsils, indicating bacterial infection. Mild cough can also accompany viral pharyngitis.

Symptoms in Children Versus Adults

In children, pharyngitis more commonly presents with systemic symptoms, meaning it affects the whole body rather than just the throat. Children often develop high fever, irritability, fatigue, and reduced appetite. Because swallowing becomes painful, many children may refuse food or fluids, which can increase the risk of dehydration. Ear pain (referred pain from the throat) is also particularly common in children due to the anatomical connection between the throat and middle ear through the Eustachian tube. Some children may experience abdominal pain or nausea, especially in bacterial pharyngitis, which can be mistaken for gastrointestinal illness.

In adults, throat-related symptoms tend to be more localized. Adults more frequently describe a scratchy, dry, or burning sensation in the throat and may be aware of swollen lymph nodes in the neck before other symptoms develop. Hoarseness may occur, especially if there is concurrent laryngeal irritation. Fever is generally less pronounced in adults compared to children. Adults may experience a longer-lasting sore throat, sometimes persisting for several days, even if other symptoms are mild or absent. Because adults are better able to describe their symptoms, diagnosis is often easier compared to young children who cannot verbalize their discomfort.

When to Seek Medical Attention

Medical evaluation is necessary if symptoms worsen or persist beyond a week. Immediate care is advised for difficulty breathing, severe pain, or inability to swallow liquids.

Signs requiring urgent attention include:

High fever over 39°C (102°F)
Swelling causing blocked airways
Drooling or excessive throat secretions
Rash accompanying the sore throat

Diagnosis of Pharyngitis

A clinical evaluation begins with a careful inspection of the throat. The healthcare provider looks for redness, swelling, and the presence of exudates (white or yellow pus-like patches) on the tonsils or pharyngeal walls, which are more suggestive of bacterial infection. The tonsils may also appear enlarged.

The clinician will palpate (gently press on) the cervical lymph nodes in the neck to assess for enlargement or tenderness, which indicates immune system activity in response to infection. Additional signs such as palatal petechiae (tiny red spots on the roof of the mouth), a coated or inflamed tongue, or a foul-smelling breath may help narrow down the cause.

Vital signs, including temperature, heart rate, and breathing rate, may be assessed to determine the severity of illness. The ears and nose are often examined as well to check for related infections, such as otitis media (middle ear infection) or sinusitis, which can occur alongside pharyngitis.

Laboratory Testing

When a bacterial cause is suspected, particularly Group A Streptococcus (GAS), laboratory testing is often performed.

Rapid Antigen Detection Tests (RADTs): These tests can detect streptococcal bacteria within minutes using a simple throat swab. They are highly specific, meaning a positive result is usually accurate. However, because they are slightly less sensitive, a negative result may need confirmation with a throat culture if symptoms strongly suggest strep throat.
Throat Culture: This is considered the gold standard for diagnosing bacterial pharyngitis. A swab from the throat is placed on a culture medium and observed for bacterial growth. Although results take one to two days, throat cultures are more reliable than rapid tests in detecting GAS and other bacteria.
Blood Tests: A complete blood count (CBC) may be used to help distinguish viral from bacterial causes. A higher neutrophil count typically suggests bacterial infection, while a higher lymphocyte count is more consistent with viral illness. In suspected infectious mononucleosis (EBV infection), additional blood tests such as a heterophile antibody test may be performed.

Differential Diagnosis

Because many illnesses can cause throat pain, pharyngitis must be differentiated from other conditions with overlapping symptoms. Infectious mononucleosis, for instance, often presents with profound fatigue, swollen lymph nodes, and an enlarged spleen, requiring distinct diagnostic testing. Diphtheria, though now rare in vaccinated populations, causes a thick gray membrane in the throat and requires urgent treatment.

Peritonsillar abscess, a complication of bacterial tonsillitis, presents with severe unilateral throat pain, difficulty opening the mouth (trismus), and a muffled “hot-potato” voice. This condition requires emergency evaluation.

Non-infectious conditions, including allergies, gastroesophageal reflux disease (GERD), and chemical or smoke irritation, can also mimic pharyngitis. These conditions are managed differently and must be recognized to avoid unnecessary antibiotics.

Treatment Options for Pharyngitis

Home management plays an important role in relieving symptoms and supporting recovery, particularly for viral and non-infectious cases. Warm salt-water gargles help reduce swelling by drawing fluid out of inflamed tissues and can also loosen mucus. Hydration is especially important because a dry throat worsens pain; warm fluids such as herbal teas, soups, or broths soothe irritated tissue, while cool beverages may relieve burning sensations.

Using a humidifier or vaporizer adds moisture to indoor air, preventing dryness that can irritate the throat lining, especially during sleep. Rest is essential to allow the immune system to function optimally.

Additional measures include:

Throat lozenges or sprays, which may provide temporary numbing and pain relief.
Honey, which has natural soothing and mild antimicrobial properties (not recommended for infants under 1 year due to the risk of botulism).
Avoiding irritants such as cigarette smoke, alcohol-based mouthwashes, or chemical fumes, which can worsen inflammation.
Consuming soft foods and avoiding spicy or acidic foods that may aggravate pain.

These supportive measures are generally sufficient for mild to moderate viral pharyngitis, which usually improves within a few days.

Medications

Medication choice depends on the cause of inflammation:

1. Bacterial Pharyngitis

The most common bacterial cause, Group A Streptococcus (GAS), requires antibiotic therapy to shorten illness duration, reduce transmission, and prevent complications such as rheumatic fever.
Penicillin and amoxicillin are the first-line treatments because they are highly effective and well tolerated.
For individuals allergic to penicillin, macrolides such as azithromycin or clarithromycin are commonly used.
Completing the full course of antibiotics is essential, even if symptoms improve early, to prevent recurrence and antibiotic resistance.

2. Viral Pharyngitis

Antibiotics are ineffective against viruses and are not prescribed.
Pain and fever can be managed with analgesics such as acetaminophen (paracetamol) or ibuprofen.
Non-steroidal anti-inflammatory drugs (NSAIDs) reduce inflammation and improve comfort.
In cases of severe throat swelling or intense pain, short courses of corticosteroids may be prescribed to reduce inflammation, though this is reserved for more severe or complicated cases.

3. Non-Infectious Pharyngitis

When inflammation is caused by allergies, antihistamines or nasal corticosteroid sprays may be used.
Pharyngitis related to acid reflux (GERD) is treated with lifestyle changes and acid-suppressing medications such as proton pump inhibitors (PPIs) or H2 blockers.
Avoidance of triggers, including smoke, chemicals, or extreme vocal strain, is the cornerstone of treatment.

Surgical Interventions

Surgical management is uncommon and generally only considered when pharyngitis is persistent or caused by recurrent infections associated with tonsillar disease. A tonsillectomy, the surgical removal of the tonsils, may be recommended in individuals who experience frequent or severe tonsillitis that contributes to ongoing pharyngeal inflammation.

Candidates for tonsillectomy typically meet criteria such as:

Multiple documented infections within a year (e.g., seven or more episodes in one year, or fewer episodes per year over multiple consecutive years),
Complications such as obstructive breathing or sleep disturbances,
Chronic infection not responding to medical therapy.

Because surgery carries risks such as bleeding, pain, and anesthesia-related complications, it is considered only after conservative treatments have failed. Referral to an otolaryngologist (ENT specialist) is usually required for evaluation.

Complications Associated With Pharyngitis

Pharyngitis can lead to several complications that vary in severity and duration. These include immediate effects from the infection, persistent symptoms, and rare but serious systemic consequences.

1. Acute Complications

Acute complications typically present during the active illness or shortly after the onset of symptoms. They are more commonly associated with bacterial pharyngitis, especially Group A β-hemolytic Streptococcus (GAS).

Peritonsillar Abscess (Quinsy)

This is the most frequent deep neck space infection secondary to pharyngitis. It occurs when an infection spreads beyond the tonsillar capsule into surrounding soft tissues, leading to progressive pus collection near the tonsil. Typical clinical features include:

Severe unilateral throat pain
“Hot potato” or muffled voice
Uvular deviation to the unaffected side
Difficulty swallowing or drooling due to painful dysphagia
Trismus (difficulty opening the mouth) due to spasm of masticatory muscles

If untreated, the abscess may enlarge, compromising the airway or spreading to deeper neck structures. Management involves aspiration or incision and drainage, followed by antibiotic therapy.

Retropharyngeal Abscess

This is more common in children due to the abundance of retropharyngeal lymph nodes. The infection spreads into the retropharyngeal space and can rapidly lead to airway obstruction or mediastinitis, a life-threatening extension into the chest cavity. Warning signs include neck stiffness, drooling, noisy breathing (stridor), and systemic toxicity.

Acute Otitis Media and Sinusitis

The infection may extend through the Eustachian tube or nasal passages, particularly in children. Fluid accumulation behind the eardrum causes pain, fever, and hearing difficulties, while sinus involvement leads to facial pressure and purulent nasal discharge.

2. Immune-Mediated Complications

Some complications are not caused by direct infection but result from an immune response against the bacteria that cross-reacts with human tissues. These typically occur 1–3 weeks after the initial sore throat, especially when the primary infection is inadequately treated.

Rheumatic Fever

Acute rheumatic fever arises due to an autoimmune response triggered by Group A Streptococcus. The immune system mistakenly targets body tissues—especially the heart (carditis), joints (migratory arthritis), brain (Sydenham chorea), and skin. Cardiac involvement is the most serious concern, as damage to heart valves can become permanent, leading to rheumatic heart disease.

Children between 5 and 15 years are particularly vulnerable. Timely antibiotic treatment of strep pharyngitis significantly reduces the risk.

Post-Streptococcal Glomerulonephritis (PSGN)

This condition presents as kidney inflammation following streptococcal infection. Symptoms include dark or cola-colored urine, swelling of the face or legs, and reduced urine output. The immune complexes that form in response to the bacteria deposit in the kidneys, triggering inflammation. Most patients recover completely, but severe cases may lead to long-term renal impairment.

3. Chronic Pharyngitis

Chronic pharyngitis is characterized by persistent or recurrent throat inflammation lasting weeks to months. Unlike acute infections, chronic pharyngitis is often triggered by environmental or physiological irritants rather than pathogens alone. Contributing factors include:

Continuous exposure to cigarette smoke or air pollutants
Repeated respiratory infections
Chronic mouth breathing or nasal obstruction
Allergies causing postnasal drip
Gastroesophageal reflux disease (GERD), where stomach acid intermittently flows back into the throat
Persistent low-grade bacterial colonization

Patients often experience constant scratchiness, thick mucus in the throat, a lingering dry cough, or the sensation of a “lump in the throat”. The condition may interfere with everyday activities such as swallowing, speaking, or professional voice use (e.g., for singers or teachers). Management focuses on eliminating irritants, optimizing hydration, and treating underlying contributors such as reflux or allergic rhinitis.

Severe Outcomes

Though uncommon, untreated or improperly managed pharyngitis can evolve into life-threatening conditions.

Scarlet Fever

This complication is associated with toxin-producing strains of Group A Streptococcus. It presents with a sandpaper-like rash, strawberry tongue, and flushed cheeks, typically in school-aged children. Without treatment, it can progress to rheumatic fever or spread to other organs.

Deep Neck Space Infections

The infection may spread to surrounding deep tissues, leading to:

Parapharyngeal abscess
Ludwig’s angina (a rapidly progressive cellulitis of the submandibular space)

These infections can cause swelling that narrows or blocks the airway, necessitating emergency intervention to prevent suffocation.

Sepsis and Septic Shock

Very rarely, bacterial pharyngitis can enter the bloodstream, leading to widespread infection. This results in systemic inflammation, multi-organ failure, and shock if untreated. It is more likely in individuals with weakened immune systems, such as the elderly, diabetics, or patients on immunosuppressive therapy.

Prevention of Pharyngitis

Regular, thorough handwashing for at least 20 seconds with soap and running water physically removes dirt, viruses, and bacteria, breaks down the lipid envelopes of respiratory viruses (such as coronaviruses and influenza viruses), and prevents self-inoculation when individuals touch their mouth, nose, or eyes.
Alcohol-based hand sanitizers containing ≥60% ethanol are appropriate when soap and water are not immediately available.
Covering the nose and mouth with the elbow crease or a disposable tissue when coughing or sneezing helps reduce airborne spread, especially in crowded or enclosed environments.
Prompt disposal of used tissues followed by hand hygiene is essential to breaking chains of transmission.
Pharyngitis-causing pathogens can survive on surfaces for several hours, making regular disinfection of high-touch objects such as doorknobs, light switches, keyboards, shared telephones, and school or office equipment necessary to reduce indirect transmission.
In institutional settings like schools, daycare centers, and dormitories, routine surface cleaning protocols significantly lower the risk of outbreaks.
Avoiding close contact with infected individuals is most crucial during symptomatic periods when viral shedding is highest.
In households, using separate utensils, towels, or cups for the infected person helps contain spread.
In workplaces and schools, staying home while symptomatic prevents wider community transmission.

Vaccination

Although no vaccine specifically targets all forms of pharyngitis, immunization plays a crucial indirect preventive role by reducing the prevalence of infections that can either cause or predispose individuals to throat inflammation.

Seasonal influenza frequently presents with sore throat and paves the way for secondary bacterial infections. Annual flu vaccination reduces pharyngitis indirectly by preventing primary respiratory infection and decreasing complications.

Immunization against Streptococcus pneumoniae and Haemophilus influenzae type b dramatically reduces the risk of invasive respiratory diseases, particularly in children, the elderly, and immunocompromised individuals. These infections can extend to the pharynx or trigger systemic involvement that exacerbates throat inflammation.

Routine childhood vaccine schedules (including DTaP, MMR, and Hib) help sustain herd immunity, limiting the circulation of infectious agents within communities. This protects vulnerable groups such as newborns, pregnant women, and individuals with chronic illnesses.

Lifestyle Changes

Adequate hydration keeps the mucous membranes lining the throat moist, improves mucociliary clearance, and reduces micro-injury to the epithelium that can allow pathogens to invade.
Cigarette smoke (active and passive), environmental pollutants, and indoor irritants impair the protective mucosal lining of the throat, increase local inflammation, and weaken immune defenses.
Avoiding smoking and ensuring good indoor ventilation significantly reduces throat irritation and infection risk.
A nutrient-dense diet rich in antioxidants (vitamins A, C, E), zinc, and other micronutrients enhances immune surveillance in the respiratory tract and supports epithelial repair, immune cell function, and antibody production.
Citrus fruits and berries are good sources of vitamin C.
Leafy greens and carrots are good sources of vitamin A.
Nuts and seeds provide vitamin E and zinc.
Probiotic foods such as yogurt help support the throat and gut microbiome.
Moderate, regular physical activity improves immune function by enhancing circulation of immune cells.
Chronic stress raises cortisol and suppresses immunity, increasing susceptibility to infection.
Relaxation practices, mindfulness, breathing exercises, prayer, or yoga, help reduce stress and restore physiologic immune balance.
Poor sleep weakens both innate and adaptive immunity, while consistently obtaining 7–8 hours of quality sleep strengthens the body’s defenses against viral pathogens that commonly cause pharyngitis.

Prognosis and Recovery

Pharyngitis generally has a favorable prognosis. Most cases, especially viral ones, resolve within 3 to 7 days without complications.

Recovery depends on the cause; bacterial pharyngitis, such as streptococcal infection, typically improves within 24 to 48 hours after starting antibiotics. Untreated bacterial cases may lead to complications.

Patients are advised to rest and maintain hydration. Symptomatic treatment, including analgesics and throat lozenges, can aid comfort during recovery.

Factors influencing recovery include age, immune status, and presence of other medical conditions. Chronic or recurrent pharyngitis may require further evaluation.

Factor	Impact on Recovery
Viral origin	Usually self-limiting, quick recovery
Bacterial origin	Requires antibiotics, quicker symptom resolution
Immunocompromised status	Prolonged recovery or complications
Age (children/elderly)	Variable, sometimes prolonged course

Patients are usually no longer contagious after 24 hours of appropriate antibiotic treatment. Follow-up is recommended if symptoms worsen or persist beyond 10 days.

Pharyngitis in Special Populations

Pharyngitis presents different clinical challenges depending on the patient’s age and immune status. Variations in symptoms, risk of complications, and treatment approaches should be considered carefully in specific groups.

Children

Children are more commonly affected by viral pharyngitis but are also at risk for bacterial infections such as group A streptococcus (GAS). Symptoms in children often include sore throat, fever, and tender cervical lymphadenopathy. Rapid antigen detection tests (RADT) are useful for confirming GAS in pediatric cases.

Untreated streptococcal pharyngitis in children can lead to rheumatic fever or post-streptococcal glomerulonephritis. Antibiotic therapy, typically penicillin or amoxicillin, is essential to reduce these risks and prevent transmission. Supportive care with analgesics and hydration supports symptom relief.

Elderly

Pharyngitis in elderly patients may present atypically, with less pronounced sore throat or fever. They have an increased risk of complications due to comorbidities and age-related decline in immune function. The differential diagnosis should include neoplasms, fungal infections, and other non-infectious causes.

Bacterial infections in this demographic may require more aggressive treatment and close monitoring. Polypharmacy and drug interactions must be considered when prescribing antibiotics.

Immunocompromised Individuals

Immunocompromised patients, including those with HIV, cancer, or on immunosuppressive therapy, are at increased risk of severe and atypical pharyngitis. Fungal pathogens (e.g., Candida), viral agents (e.g., cytomegalovirus, herpes simplex), and opportunistic bacteria are common causes.

Treatment must be tailored based on pathogen identification and immune status, often combining antimicrobials with immune support. Prompt intervention is critical to prevent systemic spread.