Throat Infection: Causes, Symptoms, Testing and Care

A throat infection can have several causes. This guide explains the symptoms, the purpose of testing, practical care and the warning signs that change how quickly to seek help. ¹

Educational information checked against the listed sources on 14 October 2026. It cannot diagnose an individual or replace medical care. Read our medical disclaimer.

What does throat infection mean?

A sore throat is a symptom, while throat infection describes one possible cause. Pain may be scratchy, burning or particularly noticeable when swallowing. Viruses cause most sore throats, and many episodes improve within about a week. A bacterial infection such as strep throat needs a different assessment, while allergies and irritation can produce similar discomfort without an infection. A red-looking throat alone does not identify the cause or establish which medicine would help. ¹

When inflammation mainly affects the tonsils, our separate tonsillitis guide explains that condition in more detail. This article covers the broader reasons for throat pain and infection.

Why symptoms overlap

One respiratory virus can affect several areas at the same time. Adenovirus, for example, can cause fever and a sore throat together with cold-like symptoms, conjunctivitis or gastrointestinal illness. That broader pattern helps explain why a person may have throat discomfort alongside red eyes, coughing or diarrhea. Adenovirus can affect people of any age and does not occur only in winter. Most infections are mild, but people with weakened immunity or existing heart or respiratory disease can become more seriously ill. There is no approved antiviral medicine specifically for ordinary adenovirus infection. Treatment generally focuses on symptoms and hydration, with medical assessment when needed. The name of a suspected virus should never be used to dismiss worsening illness. Mention eye symptoms, stomach symptoms and underlying conditions during the consultation because they help describe the complete picture. ³⁰

Strep throat, age and test interpretation

Group A streptococcus, often shortened to GAS, is an important bacterial cause of pharyngitis, meaning inflammation at the back of the throat. The Canadian Paediatric Society describes a typical pattern of fever, appreciable throat pain, tender glands toward the front of the neck and inflamed tonsils, usually without cough or a runny nose. Even this pattern is not a diagnosis. Young children can also carry GAS in the throat without it causing the current illness. A positive swab obtained during an obvious viral cold may therefore need careful interpretation. Age, local rates of rheumatic fever and the surrounding illness all affect that decision. Canadian guidance also recognizes that communities with a higher rheumatic-fever burden may need a different approach from low-risk settings. Explain relevant household exposures and past diagnoses when seeking advice. ⁹

Warning signs that need faster medical help

A baby younger than three months with a temperature of 38°C (100.4°F) or higher needs medical advice immediately. ¹

Breathing difficulty and inability to swallow

The epiglottis is a flap near the entrance to the windpipe. If it becomes swollen, the airway can narrow quickly. Epiglottitis is uncommon but illustrates why a very sore throat accompanied by breathing difficulty or drooling is an emergency. Affected people may prefer to sit upright or lean forward; a child may resist lying down. Call emergency services, keep the person in the position that makes breathing easiest and follow the dispatcher’s instructions. Do not make them lie flat or drive themselves to hospital. The immediate priority is protecting breathing, which may require hospital equipment and specialist care. There is no need to identify the exact cause before calling. Tell the dispatcher about changes in breathing, color, alertness or swallowing, and give a location where an ambulance can find you. ²⁷

Severe one-sided symptoms or neck stiffness

A collection of pus beside a tonsil or in deeper neck tissues can cause symptoms that differ from an uncomplicated sore throat. The Royal Children’s Hospital guideline highlights a muffled voice, difficulty opening the mouth, drooling, a swollen or stiff neck and a child holding the head unusually. These findings need urgent in-person assessment, especially with fever or severe pain. If breathing or swallowing is affected, use emergency services. A child with possible airway obstruction should be kept calm with minimal handling. Do not force the mouth open or try to inspect deep inside the throat at home. Clinicians may arrange specialist review, imaging or treatment in hospital according to the findings. Waiting for a routine appointment or assuming that an earlier negative strep test makes these symptoms harmless can delay the assessment that is needed. ³

Watch fluid intake and alertness

Painful swallowing can lead to dehydration because a person drinks less than usual. Watch for darker urine, urinating less often, a dry mouth, dizziness or unusual tiredness. In babies, fewer wet nappies or diapers, few tears, sunken eyes and unusual drowsiness or irritability are useful warning signs. Small, frequent drinks may be easier than a large glass when swallowing is still safe. Continue usual breast or formula feeds for infants, offering smaller feeds more often if needed. Seek prompt advice when fluid intake is inadequate or dehydration is suspected, particularly in a young child or an older person. Marked drowsiness, confusion, difficulty waking or breathing changes need emergency assessment. Do not force fluids into someone who cannot swallow safely. Note when they last drank and passed urine so the clinician can assess how the illness is affecting them. ¹⁶

Viral causes that may change the care plan

Mononucleosis or glandular fever

Infectious mononucleosis, often called mono or glandular fever, is commonly caused by Epstein–Barr virus. A sore throat may occur with fever, swollen lymph nodes and pronounced fatigue, especially in teenagers and young adults. The illness often improves over two to four weeks, although fatigue may last longer. This recovery pattern can differ from a brief cold, so a person who remains exhausted may need a review rather than repeated treatment for presumed strep. The spleen can enlarge during mono. Avoid contact sports until a healthcare professional says it is safe to return because an enlarged spleen is vulnerable to injury. Tell the prescriber if mono is suspected: ampicillin and amoxicillin should be avoided in this illness. If you are already taking an antibiotic, contact the prescriber before changing treatment yourself. Antibiotics do not treat EBV itself. Rest, fluids and an individualized recovery plan are more relevant than trying to force a rapid return to normal activity. ⁷

What an EBV blood test can and cannot show

EBV testing is different from a throat swab for strep. Clinicians sometimes use blood tests when the illness is atypical or when identifying the cause would change management. The CDC advises against general reliance on the Monospot test because false positive and false negative results occur, particularly in children. Specific EBV antibody patterns can help distinguish a recent infection from one that occurred years ago. A positive antibody result by itself does not prove that EBV explains today’s sore throat or fatigue. Some antibodies persist for life, and interpretation depends on which antibodies were measured and when symptoms began. Persistent symptoms still deserve assessment for other causes when the clinical picture does not fit, even if an old EBV infection is documented. ⁸

Influenza and early treatment decisions

When a throat illness is part of influenza, the decision about antiviral treatment can be time-sensitive. These medicines act against flu viruses and are different from antibiotics. CDC guidance says they work best when started early, ideally within two days of symptom onset. People who are very ill or at increased risk of complications should contact a healthcare professional promptly; later treatment can still help in some higher-risk or severe cases. Do not assume that missing the first two days means there is no reason to seek advice. Many otherwise healthy people with mild flu recover without antiviral treatment, so a prescription is not automatic. Record when the illness first started and describe relevant conditions, such as asthma, diabetes or heart disease. That timing and health history help the clinician decide whether treatment is appropriate and how urgently to arrange it. ¹¹

COVID-19 and people at higher risk

COVID-19 treatment is another reason not to wait for a sore throat to become severe before asking for advice when personal risk is high. Current CDC guidance recommends prompt contact about testing or treatment for higher-risk people with possible COVID-19, even when symptoms are mild. Depending on the medicine, treatment generally needs to begin within five to seven days after symptoms start. Eligibility depends on factors such as age, underlying illness and the specific treatment available. Medicines can interact with other prescriptions, so the clinician or pharmacist needs a complete medicine list. Do not borrow someone else’s antiviral treatment or stop regular medicines to make room for it. A test can help guide the next step, but seeking advice should not be delayed while waiting for a positive result. Local treatment access and recommendations may differ outside the United States. ¹²

Mouth sores in younger children

Hand, foot and mouth disease is a viral illness that can begin with fever and a sore throat before painful mouth sores and a skin rash become apparent. It is especially common in children younger than five, although older children and adults can catch it. The rash often involves the palms and soles. Most cases settle within seven to ten days, but the mouth pain can make drinking difficult. Focus on maintaining fluid intake and ask for help if the child is not drinking enough. The illness can spread through respiratory secretions, blister fluid and stool, making handwashing after diaper changes particularly useful. Returning to childcare depends on fever, ability to participate, control of drooling and local outbreak rules. A familiar rash pattern does not remove the need to assess a child who is unusually sleepy, dehydrated or otherwise becoming more unwell. ²²

How clinicians decide whether to test for strep

United States: testing and the child–adult distinction

GAS is most common at ages five to fifteen and rare in children younger than three. In US CDC guidance, clear viral features such as cough, runny nose, hoarseness or oral ulcers generally make GAS testing unnecessary. Without clear viral features, examination alone cannot reliably distinguish viral illness from strep. A rapid antigen test or throat culture can confirm GAS. For symptomatic children aged three years or older, a negative rapid antigen result should be backed up with a culture; this is not routinely needed in adults. That rule applies to antigen tests and should not be assumed to describe every molecular test. Ask which test was used and how any follow-up result will be communicated. A positive result supports antibiotic treatment. For confirmed strep, US advice is to stay home until fever has resolved and at least twelve to twenty-four hours have passed after appropriate antibiotics begin; follow local school or workplace rules. ⁴

What the IDSA 2025 update says about scores

The 2025 IDSA guideline update suggests that clinicians use a clinical score to help decide who should be tested for GAS. This is a conditional recommendation based on evidence with very low certainty. Scores combine findings such as fever, cough, neck glands, tonsillar changes and, in some systems, age. They estimate probability; they do not identify a germ or replace an examination. The recommendation does not apply to children younger than three. A low score also does not automatically end the assessment when important risks are present. The guideline highlights household exposure, a history of rheumatic fever and signs of complicated infection as reasons to strongly consider testing despite a low score. This first part of the update addresses risk assessment for testing. It should not be presented as a new complete treatment schedule or used as a do-it-yourself antibiotic calculator. ⁵

United Kingdom: NICE uses a prescribing framework

UK NICE guideline NG84 takes a different approach to uncomplicated acute sore throat. It uses FeverPAIN or Centor scores alongside clinical judgment to guide whether no antibiotic, a back-up prescription or an immediate prescription may be appropriate. Lower scores generally favor no antibiotic; intermediate and higher scores may lead to different options after considering likely benefit and possible harms. People who are systemically very unwell, have signs of serious illness or are at high risk of complications need a different response. A back-up prescription has specific instructions about when it should be used and when reassessment is needed. It is not permission to start an old antibiotic whenever throat pain returns. This UK framework should not be merged with US testing recommendations into a single worldwide rule. Ask the treating service which pathway applies locally and what should trigger another review. ⁶

Treatment: match the medicine to the cause

Use antibiotics only when they are indicated

Antibiotics treat susceptible bacteria, not viruses. Taking one for a viral throat illness will not speed that illness away, and it can still cause side effects. These range from nausea or a rash to serious allergic reactions and antibiotic-associated diarrhea, including infection with Clostridioides difficile. Unnecessary antibiotic use also contributes to resistance. If an antibiotic is prescribed, take it exactly as directed and ask the prescriber or pharmacist about missed doses, side effects or difficulty swallowing the medicine. Do not share it, use a relative’s prescription or save leftovers for another sore throat. A decision not to prescribe should still include symptom advice and a clear explanation of when to seek reassessment. New or worsening symptoms deserve attention rather than an assumption that more antibiotics must be the answer. ¹³

Comfort measures and expected recovery

For an uncomplicated sore throat, choose measures that make swallowing and resting easier. Water, cool or soft foods and avoiding smoke may help. Adults who can gargle and spit safely may find warm salt water soothing; this is unsuitable for young children. A pharmacist can advise about appropriate pain relief or throat products, taking age and other medicines into account. These measures ease discomfort but do not establish the cause or guarantee a cure. Seek a review if the sore throat has not improved after about a week, keeps returning or is accompanied by concerning symptoms. Earlier assessment is appropriate for a very high temperature, dehydration or weakened immunity. Pay attention to whether the overall course is improving, and use the emergency warning signs above if breathing or swallowing becomes difficult. ²

Read pain-relief labels carefully

Acetaminophen, called paracetamol in many countries, can relieve pain and fever when used appropriately. It is also present in many combination cold and flu products, which creates a risk of taking the same ingredient twice. Check the active ingredients of every product and follow its directions. More medicine is not a safe response when pain persists: excessive acetaminophen can cause severe liver injury. Ask a pharmacist or clinician before use when pregnancy, liver disease, other medicines or uncertainty about a product is relevant. For a child, use the correct pediatric formulation and the measuring device supplied with that product. A kitchen spoon or a device from another bottle can give an inaccurate amount. If the label does not provide clear directions for the child’s age or weight, obtain professional advice. Suspected excess dosing needs immediate poison-service or medical advice, even before symptoms appear. ¹⁴

Extra safeguards for children

Children’s medicines need attention to age, weight, formulation and the child’s current condition. Adult products should not be adapted by guesswork. NHS advice cautions against ibuprofen when a child is dehydrated or has chickenpox, and recommends checking suitability when asthma or other health problems are present. Do not give aspirin to a child under sixteen unless a doctor has specifically prescribed it. If a clinician recommends more than one medicine, ask for a clear written schedule rather than improvising an alternating routine. Record what was given, by whom and when, especially when several adults share care. Keep medicines in their original containers and out of children’s reach. Pain relief can make a child more comfortable, but it should not delay assessment when the child is becoming less alert, cannot drink or is developing other concerning symptoms. Ask the pharmacist about any uncertainty before giving another product. ¹⁵

Combination remedies are not a shortcut

A bottle marketed for coughs and colds may contain several medicines, although a child only needs help with one symptom. FDA guidance does not recommend over-the-counter cough and cold medicines for children younger than two because serious side effects can occur; manufacturers label these products against use in children younger than four. Older children still need an age-appropriate product and careful adherence to the label. Homeopathic products are not an established substitute: the FDA has not approved any homeopathic product and warns that products sold in the United States have not met its requirements for safety and effectiveness. Discuss a proposed remedy with a pharmacist rather than assuming that a familiar package, a natural-sounding name or an online testimonial establishes safety. Explain the child’s actual symptoms and what has already been given so the advice can address the problem without unnecessary ingredients. ²⁶

Can a throat infection cause a rash or later problems?

Scarlet fever needs assessment

Scarlet fever is caused by group A strep and commonly includes fever, sore throat and a rash. It occurs most often in school-age children, although other age groups can be affected. The rash may feel rough, and the tongue or skin can change as the illness develops. A rash accompanying throat pain should be described to a healthcare professional rather than treated as proof of a particular diagnosis, because several illnesses can cause that combination. Assessment determines whether strep testing and antibiotics are appropriate. Tell the clinician about exposure to a known case at home or school and when each symptom began. Complications are uncommon, but prompt assessment helps arrange the right treatment and advice about limiting spread. Follow the specific return-to-school instructions provided for the diagnosed illness and local setting. A child who becomes rapidly more unwell needs urgent reassessment regardless of the original label. ²⁴

Rheumatic fever is an immune complication

Rheumatic fever can develop after a group A strep infection, typically over the following one to five weeks. It is an inflammatory response that can affect joints, the heart, the nervous system or skin, rather than bacteria simply moving from the throat into each organ. Possible symptoms include fever, painful swollen joints, unusual involuntary movements, chest discomfort or breathlessness. Seek medical assessment for these symptoms and mention any recent throat or skin infection. A previous episode of rheumatic fever is especially important to report because it increases the risk of recurrence. This complication is not the expected outcome of an ordinary sore throat, and the risk varies between populations. Its importance helps explain why identifying and appropriately treating GAS matters. People with established rheumatic fever or rheumatic heart disease may already have an individual prevention plan; a general throat-care article cannot replace that plan. ²⁵

Changes in urine or swelling after strep

Another uncommon complication is post-streptococcal glomerulonephritis, an inflammatory kidney condition following some strep infections. After throat infection it can appear around ten days later, sometimes after the throat symptoms have eased. Dark reddish-brown urine, reduced urine output and swelling around the eyes, face, hands or feet deserve prompt medical assessment. These signs should not simply be attributed to drinking too little during the illness. Clinicians may check blood pressure, urine and kidney function and look for evidence of a recent infection. Many affected people recover, but monitoring is important because the kidneys and blood pressure may need treatment. This condition reflects the body’s immune response; it is not a strep infection inside the kidneys. Do not start leftover antibiotics or change fluid intake dramatically on your own. Describe the timing of the earlier illness and the new changes to the treating team. ²³

A persistent sore throat may have another cause

Thrush and other mouth changes

Candida is a yeast that can live in the mouth and throat without causing illness. Overgrowth can produce thrush, with white patches, redness or soreness. Candida affecting the esophagus, the tube leading toward the stomach, can cause painful or difficult swallowing. Risk is higher with some immune problems and other conditions; dentures, poorly controlled diabetes and medicines that contribute to dry mouth may also matter. These findings require a different assessment from ordinary strep throat. A clinician can examine the mouth and decide whether a sample or further investigation is needed. Confirmed candidiasis is treated with an appropriate antifungal, selected according to the site, severity and the person’s health. Antibiotics are not the treatment for this yeast infection. Seek prompt advice if swallowing is painful or difficult, especially with weakened immunity, rather than repeatedly trying products intended for an uncomplicated sore throat. ²¹

Allergy symptoms can resemble a cold

Allergic rhinitis can cause sneezing, an itchy or blocked nose, watery eyes, coughing and an itchy roof of the mouth. Symptoms often follow exposure to a trigger such as pollen, dust mites, animal dander or mould. A repeated pattern around a particular place or season is useful information when throat discomfort occurs alongside these symptoms. Allergies are not diagnosed by the appearance of the throat alone. A pharmacist can advise about suitable treatments, while symptoms that are worsening, affecting sleep or not responding to pharmacy care warrant a medical review. Mention asthma, because worsening asthma needs attention too. Keep a brief record of when the symptoms occur and what exposure preceded them. Avoid repeatedly switching medicines without checking their suitability, especially for a child. If the cause remains uncertain, a clinician can consider whether allergy, infection or another condition better explains the pattern. ¹⁹

Reflux can affect the throat and voice

Gastroesophageal reflux can cause stomach contents to come back into the esophagus, throat or mouth. Heartburn and a sour taste may occur, but not everyone with reflux disease has those familiar symptoms. Chronic cough, hoarseness and painful or difficult swallowing can also occur. This makes reflux one possible explanation for persistent throat complaints, although those symptoms alone do not establish the diagnosis. Tell a clinician about the timing, any regurgitation, medicines taken and whether swallowing has changed. Difficulty swallowing, unexplained weight loss, persistent vomiting or signs of gastrointestinal bleeding need medical assessment. Do not assume that every ongoing sore throat is reflux simply because a throat test was negative. Similarly, temporary relief after an over-the-counter product does not explain all persistent symptoms. If symptoms continue or repeatedly return, ask for a review of the cause and a plan appropriate to the findings. ¹⁸

Dryness and reduced saliva

A persistently dry mouth can make the throat feel dry or irritated and can interfere with chewing, swallowing and speaking. Saliva normally moistens food and helps protect the mouth, so a continuing shortage deserves attention. Medicines are a common contributor, but medical conditions and previous treatments can also affect saliva. A dentist or clinician can review symptoms, oral health and the medication list and decide whether further assessment is useful. Do not stop a prescribed medicine yourself because dryness appeared after starting it. Keep a record of when the discomfort is strongest and whether meals, sleep or speaking are affected. Persistent dryness also raises concerns about tooth decay and oral infections, so dental care remains relevant even when the complaint feels mainly like a throat problem. Our dry mouth guide explains the assessment and practical relief options in more detail. ²⁰

Give a strained or hoarse voice a chance to recover

Throat discomfort may accompany irritation of the voice box or heavy voice use. Teachers, singers and people who speak for long periods can notice strain, hoarseness or an effortful voice during an illness. NIDCD recommends resting the voice when it is tired or hoarse, staying hydrated and avoiding smoking and secondhand smoke. Shouting and whispering can both strain the voice, so trying to push through a full day of speaking may not help. Use breaks and amplification when appropriate instead of repeatedly raising the voice over noise. If hoarseness persists or speaking remains uncomfortable, a clinician can assess the cause and may involve an ear, nose and throat specialist or a speech-language professional. Do not assume that voice changes prove a bacterial throat infection. The duration and effect on daily communication are useful details to bring to the appointment. ¹⁷

Recovery, recurrence and follow-up

Reduce spread while you are ill

For respiratory viral illness in the United States, CDC guidance advises staying home and away from others until symptoms are improving overall and there has been no fever without fever-reducing medicine for at least twenty-four hours. After returning to usual activities, use additional precautions for the next five days, such as cleaner air, a well-fitting mask, hand hygiene, distancing or testing when relevant. This is especially useful around people who are more vulnerable to severe illness. If fever returns or symptoms worsen, stay home again and reassess the situation. Feeling better reduces but does not necessarily eliminate the possibility of transmission. Healthcare workplaces and specific infections can have different rules. Confirm the instructions that apply to the diagnosed illness, school or employer rather than using one timetable for every sore throat. Make arrangements for meals, caregiving or work that allow recovery without unnecessary close contact. ¹⁰

Recurring throat pain does not automatically mean surgery

Repeated episodes need a record of what actually happened: dates, fever, examination findings, test results, treatment and the effect on school or work. The EBI guidance on tonsillectomy emphasizes that not every sore throat is tonsillitis. Removing the tonsils will not address a different source of throat symptoms. For recurrent, disabling tonsillitis, a specialist may discuss observation and surgery, considering the pattern of illness, complications, quality of life and the procedure’s risks. That is a separate decision from treating today’s sore throat. Pain, bleeding and recovery time after surgery are part of the discussion, so referral does not automatically mean an operation is needed. Bring records of previous episodes rather than relying only on a rough count from memory. A person with severe or unusual recurring symptoms may need an individualized assessment even when their pattern does not fit a simple numerical threshold. ²⁹

Persistent symptoms deserve a fresh assessment

A sore throat that does not go away, a neck lump, a mouth or throat sore that fails to heal, ongoing swallowing difficulty or persistent voice change should be assessed. These symptoms often have less serious explanations, but they can also occur with head and neck cancers and should not be repeatedly dismissed as infection. Mention persistent one-sided discomfort, ear pain and any unexplained change in weight or eating. A clinician or dentist can examine the relevant area and decide whether specialist assessment is needed. The purpose of this review is to establish the cause, not to assume a cancer diagnosis from a symptom list. A previous course of antibiotics or an earlier reassuring test does not explain a new or continuing problem by itself. Record how long the symptoms have been present and whether they are changing, so that the next consultation starts with a clear timeline. ²⁸

Leave the consultation with a clear next step

Before the appointment, write down when symptoms started, what changed and which questions matter most. Bring the names of regular medicines and any products already tried, together with information about previous tests. During the consultation, ask what the current assessment is, whether a test is being sent and how the result will reach you. If a prescription is provided, confirm its purpose and the instructions. If no prescription is needed, ask what improvement to expect and when to arrange another review. Write down the contact route for help outside normal hours and who will review any pending result. For a child, share the plan with the other adults providing care so that information and medicine records remain consistent. Keep the plan available to every caregiver.

Frequently asked questions

Do white patches prove that a throat infection is strep?

No. Appearance alone cannot confirm strep. A clinician decides whether testing is needed. ⁹

Can I use leftover antibiotics for another sore throat?

No. Take antibiotics only as prescribed for the current illness. ¹³

What should I ask when a throat swab is taken?

Ask which test is being used, when the result is expected and who will explain any next step.

Is a positive EBV antibody result always a new infection?

No. Some antibodies persist for life; the pattern and current symptoms need interpretation. ⁸