Swollen Throat: Causes and First Aid

Throat swelling is not a diagnosis, but a symptom complex: excessive fluid accumulation in the tissues of the pharynx or larynx, which narrows the airway and causes hoarseness, a lump in the throat, and difficulty swallowing and breathing. Causes vary, ranging from allergic reactions and sudden angioedema to infections (e.g., of the epiglottis), injuries, burns, and drug reactions. In severe cases, the condition is dangerous due to its rapid progression and the risk of suffocation, so the key to a good outcome is early recognition and appropriate, step-by-step treatment. [1]

The clinical picture depends on the level of the lesion. With laryngeal edema, breathing is more rapidly affected: noisy inhalation, stridor, and intercostal retractions occur. With a predominantly pharyngeal component, pain and difficulty swallowing predominate. Adults often have a more stable condition than children, as their airway is narrower and any edema is more severe. However, fulminant forms are possible in adults, especially with angioedema or deep neck infections. [2]

It's important to distinguish between two fundamentally different mechanisms: histamine-mediated edema (more common in allergies and immediate reactions) and bradykinin-mediated edema (typical of hereditary angioedema and edema associated with angiotensin-converting enzyme inhibitors). This determines the choice of medication: adrenaline, antihistamines, and glucocorticosteroids are effective in histamine-mediated edema, but are ineffective in bradykinin-mediated edema, which requires specific agents. [3]

Throat swelling can mask various conditions, including acute epiglottitis (inflammation of the epiglottis), peritonsillar abscess, cervical cellulitis, angioedema, burns, and foreign bodies. Therefore, the diagnostic process is structured as a "ladder": a parallel assessment of the airway and its causes, minimizing manipulations that could worsen patency, and early involvement of respiratory specialists. [4]

Code according to the International Classification of Diseases, 10th and 11th revisions

In the International Classification of Diseases, Tenth Revision, the most accurate code for laryngeal edema proper is J38.4 "Laryngeal edema." It includes the subtypes "glottic edema," "infraglottic," and "supraglottic" edema. In the practice notation, a causal code (e.g., "drug reaction," "anaphylaxis") or a complicating condition code (e.g., "neck abscess") is often added to reflect the etiology. [5]

In the International Classification of Diseases, Eleventh Revision, laryngeal edema is classified under the heading of upper respiratory tract diseases as CA0H.3 "Laryngeal edema." If the edema is part of angioedema, the appropriate categories are used (e.g., EB04 "Angioedema"; for hereditary forms, specialized codes are used). In real-life cases, the "site" (larynx) and "mechanism" (anaphylaxis, angioedema) codes are often combined to maintain clinical relevance. [6]

Table 1. Examples of throat swelling coding

Clinical situation	International Classification of Diseases, 10th revision	International Classification of Diseases, 11th revision
Isolated laryngeal edema	J38.4	CA0H.3
Laryngeal edema in anaphylaxis	J38.4 + T78.2 (anaphylactic shock, unspecified) or T78.4 (allergic reaction)	CA0H.3 + MC71 (anaphylaxis, appropriate category)
Angioedema with laryngeal involvement	T78.3	EB04 (angioedema) + CA0H.3 (if necessary)
Edema in infectious epiglottitis	J38.4 + J04/J05/J39 by clinic	CA0H.3 + CA0B.0 (epiglottitis)

Epidemiology

The incidence of clinically significant pharyngeal edema varies depending on the cause. For anaphylaxis, global estimates range from approximately 50 to 112 episodes per 100,000 person-years, with a lifetime prevalence of approximately 0.3–5.1%. However, in children, the incidence range is wider due to methodological differences (from 1 to 761 per 100,000 person-years). Despite the increase in hospitalizations, mortality remains low. [7]

Acute epiglottitis in childhood has become extremely rare since the introduction of the Haemophilus influenzae type B vaccination (e.g. in Denmark after the start of vaccination - about 0.02 cases per 100,000 per year in children), but in adults the overall incidence remains at about 1.9 cases per 100,000 per year; however, the proportion of patients requiring airway intervention has decreased from about 18.8% to 10.9% in recent decades. [8]

Angiotensin-converting enzyme inhibitor-induced angioedema occurs in approximately 0.1–0.7% of patients (up to 1.6% in some cohorts), with the highest risk in the first month of use. In people of African descent, the risk is 3–5 times higher compared to non-African populations.[9]

Deep neck infections (originating in teeth, tonsils, and salivary glands) are less common but potentially dangerous due to rapid progression and airway compromise. According to reviews, this is a relatively rare but serious condition with significant morbidity and the need for multidisciplinary management. [10]

Reasons

Large etiologic groups: immediate-type allergic reactions (including anaphylaxis to foods, drugs, insect venoms), histamine-mediated angioedema, bradykinin angioedema (hereditary, acquired, and drug-induced when taking angiotensin-converting enzyme inhibitors), upper respiratory tract infections (epiglottitis, peritonsillar abscess, deep phlegmon of the neck), trauma and burns (including inhalation), chemical injuries, and foreign bodies. [11]

In adults, a significant proportion of the cases are due to medications: angiotensin-converting enzyme inhibitors, less commonly angiotensin receptor blockers and dipeptidyl peptidase-4 inhibitors. These reactions often occur suddenly, without urticaria, and respond poorly to antihistamines and glucocorticosteroids. [12]

The vaccine era has changed the picture of epiglottitis: in children, the incidence has dropped sharply, while in adults, the proportion of bacterial causes other than Haemophilus influenzae (streptococci, staphylococci), as well as viral-bacterial combinations, has increased. This is reflected in the choice of empirical antibacterial therapy. [13]

Odontogenic infections, diabetes, immunosuppression, trauma, and tongue piercing increase the risk of deep cervical space involvement, leading to cellulitis and secondary pharyngeal and laryngeal edema. Early visualization and timely airway management are critical here. [14]

Risk factors

For anaphylaxis - the presence of food, drug or poison sensitization, bronchial asthma, young age groups for food causes; for drug causes - old age and concomitant polypharmacy. The risk of recurrence of anaphylaxis over the years of observation reaches 26.5-54.0%. [15]

For bradykinin-induced angioedema, the following are associated: use of angiotensin-converting enzyme inhibitors, African descent, the first 30 days of therapy, advanced age, previous drug rashes, and seasonal allergies. Hereditary forms tend to have a familial pattern with onset in adolescence. [16]

For epiglottitis in adults, the risk factors include lack of childhood vaccination, smoking, alcohol abuse, diabetes, and immunosuppression. In children, lack of vaccination remains the most significant risk factor for severe forms. [17]

For deep neck infections - poor dental health, diabetes, oral trauma, injections and interventions in the neck area, and delay in seeking help. [18]

Pathogenesis

In a histamine-mediated reaction, mast cells release mediators (histamine, leukotrienes), blood vessels become permeable, and the liquid portion of the blood leaks into the tissues, resulting in swelling of the laryngeal and pharyngeal mucosa. This condition is often accompanied by itching, urticaria, and anaphylaxis and responds well to adrenaline, antihistamines, and glucocorticosteroids. [19]

The bradykinin mechanism increases the activity of the kallikrein-kinin system, producing excess bradykinin, which dramatically increases vascular permeability. This is how hereditary angioedema and edema associated with angiotensin-converting enzyme inhibitors work. Classic "antiallergic" drugs are ineffective here; drugs that block the bradykinin pathway or replenish C1 inhibitor levels are needed. [20]

In infections of the epiglottis, tonsils, and deep spaces of the neck, inflammation and microbial toxins cause swelling, hyperemia, infiltration, and sometimes abscess formation. Even a moderate increase in tissue volume in anatomically narrow areas dramatically impairs airway clearance and ventilation, which explains the need for careful diagnosis and early airway monitoring. [21]

Edema can be aggravated by mechanical factors such as coughing, straining, and lying down. Therefore, transport and examination are carried out gently, leaving the patient in the most comfortable position and avoiding repeated attempts at instrumental examination without being prepared to secure the airway. [22]

Symptoms

Allergic and histamine-mediated edema often develops rapidly: hoarseness, shortness of breath, stridor, a feeling of fullness in the throat, possible itching and hives, a drop in blood pressure, and nausea appear. As symptoms worsen, signs of an anaphylactic reaction appear, requiring immediate administration of adrenaline. [23]

Bradykinin-induced angioedema often occurs without itching or urticaria, develops over a period of hours, and can affect the tongue, lips, soft palate, larynx, and gastrointestinal tract (colicky pain). There is a link with the initiation of therapy with angiotensin-converting enzyme inhibitors or a family history of hereditary angioedema. [24]

Epiglottitis in adults presents with pain when swallowing, salivation, a muffled "hot potato" voice, fever, and rapid respiratory fatigue; in children, it presents with more pronounced stridor and a forward-leaning sitting posture. Significant hyperemia of the pharynx is not always present, making the condition "hidden" and prone to late diagnosis. [25]

Deep neck infections cause increasing pain, neck asymmetry, tenderness when turning, trismus, sometimes a bulging tonsil (peritonsillar abscess), foul odor, and fever. Any signs of progressive difficulty breathing warrant immediate evaluation of the airway. [26]

Classification, forms and stages

Based on the mechanism, edema is classified as histamine-mediated (allergy, anaphylaxis), bradykinin-induced (hereditary and drug-induced), inflammatory-infectious (epiglottitis, peritonsillar abscess, cervical cellulitis), traumatic, thermochemical, and mixed. This division determines the first line of therapy. [27]

By level - pharyngeal (nasopharynx and oropharynx), supraglottic (epiglottis and supraglottic space), vocal, subglottic, and mixed. The lower the level, the higher the risk of critical narrowing of the lumen, especially in children. [28]

According to the dynamics - acute (minutes-hours), subacute (hours-days) and chronic recurrent (weeks-years, for example, in hereditary angioedema). According to the severity - without a threat to breathing, with a threat (stridor, retractions) and life-threatening (decreased oxygen saturation, respiratory exhaustion, voice fading). [29]

For infectious forms, staging is used based on the presence of abscess formation and involvement of the neck spaces; for the peritonsillar process, an infiltrative stage, abscess, and complications (spread below the hyoid bone) are distinguished. [30]

Table 2. Clinical classification of throat edema

Criterion	Options	Significance for tactics
Mechanism	Histamine, bradykinin, infectious, traumatic, mixed	Determines the choice of "first minute" drugs
Level	Pharynx, epiglottis, glottis, subglottic space	Assesses the risk of critical obstruction
Dynamics	Acute, subacute, chronic recurrent	Affects the scope of the examination
Heaviness	No threat, threat, life-threatening	Determines the airway management algorithm

Complications and consequences

The primary danger is rapid airway obstruction, leading to asphyxia. This is typical of progressive laryngeal edema of any origin, especially with bradykinin-mediated laryngeal edema and epiglottitis. The risk is higher with delayed treatment and careless diagnostic procedures without proper airway management. [31]

Infectious forms can be complicated by mediastinitis, sepsis, jugular vein thrombosis (Lemierre's syndrome), and bleeding from eroded vessels. Timely visualization and drainage radically reduce these risks. [32]

In patients with drug-induced angioedema, recurrent episodes are possible even months after drug discontinuation, especially if there are concurrent risk factors. Therefore, it is important to document the "prohibited" group of medications in the medical record and educate the patient on the action plan. [33]

Psychological sequelae (fear of food, panic episodes), as well as post-intubation edema and cicatricial stenosis, are rare but possible, especially after multiple intubation attempts. This is an argument in favor of choosing a "safe" airway strategy the first time. [34]

When to see a doctor

Immediately - with increasing noisy inhalation, hoarseness, difficulty breathing, cyanosis, salivation, inability to swallow saliva, sudden enlargement of the tongue or lips, or the appearance of hives with dizziness. These signs correspond to a "threatening" profile. [35]

Urgently - if swelling occurs after starting an angiotensin-converting enzyme inhibitor, or if there are family history of angioedema, or if high fever, severe sore throat, and trismus persist (suspected peritonsillar abscess or phlegmon). [36]

Planned, but without delay - in case of slowly increasing sensations of a “lump”, nasal voice, discomfort when swallowing without respiratory failure, especially in smokers and patients with reflux, in order to exclude chronic inflammatory and tumor causes. [37]

When in doubt, they focus on the worst-case scenario: it is better to show the patient to a specialist again than to miss dangerous dynamics in a narrow airway. [38]

Diagnostics

The first step is a simultaneous assessment of the airway and vital signs. This includes oxygen saturation, respiratory rate, voice ("whisper," "hot potato"), the child's posture, and the presence of stridor. If there are signs of a threat, immediate airway management is initiated with the involvement of an experienced team. [39]

The second step is a targeted examination of the throat with sparing maneuvers. In a stable patient, flexible nasofiber laryngoscopy is used to visualize the epiglottis and glottis; in an unstable patient, this is done only if the airway is immediately secured. For a peritonsillar process, the pharynx is examined, palpated, and, if necessary, a puncture is performed. [40]

The third step is laboratory tests as indicated: a complete blood count, inflammatory markers, and, if hereditary angioedema is suspected, the level and functional activity of the C1 inhibitor, and the level of the C4 component. In case of anaphylaxis, tryptase (preferably in the early hours) is performed; however, the clinical picture is primary and should not delay treatment. [41]

The fourth step is imaging. If a deep neck infection is suspected, the "gold standard" is a contrast-enhanced CT scan of the neck to define spaces and plan drainage; for epiglottitis in adults, a lateral neck radiograph (the "thumb sign") is sometimes performed, but increasingly the diagnosis is confirmed endoscopically. [42]

Table 3. Minimum required diagnostic algorithm

Situation	What do we do first?	What do we do next?
Signs of a threat to breathing	We call an experienced team, administer oxygen, and prepare equipment for “awake” intubation.	Decision about intubation or tracheostomy
Suspected epiglottitis	Endoscopic imaging in a stable patient	We start antibiotics and discuss steroids.
Suspected peritonsillar abscess	Examination, puncture if necessary	Drainage + antibiotics
Suspected deep phlegmon	Computed tomography with contrast	Drainage + broad-spectrum antibiotics

Differential diagnosis

Histamine-mediated and bradykinin-mediated edema are distinguished by context and accompanying factors: itching, urticaria, contact with an allergen, and a response to adrenaline are characteristic of histamine-mediated edema; slow onset, absence of itching and urticaria, association with an angiotensin-converting enzyme inhibitor, or a family history are characteristic of bradykinin-mediated edema. This is the key to choosing the correct treatment. [43]

Edema associated with anaphylaxis is distinguished from epiglottitis and peritonsillar abscess by the absence of localized purulent symptoms and the positive effect of immediate adrenaline therapy. Epiglottitis most often presents with salivation, severe pain when swallowing, and a "quiet" voice. Peritonsillar abscess is characterized by uvula displacement, tonsil asymmetry, and trismus. [44]

Deep cervical phlegmons mimic "common tonsillitis," but the pain is "deeper," asymmetry increases, and pain occurs when turning the head; at the slightest doubt, a CT scan is performed. Finally, inhalation trauma, chemical burns, and foreign bodies are separate scenarios where circumstances and X-ray endoscopy are important. [45]

Table 4. Differential diagnostic clues

Sign	More for histamine swelling	More for bradykinin edema	More for infection
Itching and hives	Yes	Usually no	Usually no
Relationship with the drug	Any (antibiotic, food)	Angiotensin-converting enzyme inhibitor	Less common (but possible)
Pain, fever, trismus	Rarely	Rarely	Often
The effect of adrenaline	Distinct	Weak/none	Indirect (relieves swelling, but does not treat the cause)

Treatment

First minute: Airway security is paramount. If rapidly progressing obstruction is suspected, a strategy of "awake" intubation is developed while maintaining spontaneous breathing, oxygen is administered, and oxygen saturation and pulse are monitored. Sedation and muscle relaxation are used only when the team is ready to immediately secure the airway; otherwise, there is a risk of a "can't ventilate, can't intubate" situation. In complex cases, "awake" techniques with a flexible bronchoscope and readiness for surgical access are preferred. [46]

Histamine-mediated edema and anaphylaxis: The main treatment is immediate intramuscular injection of epinephrine into the mid-thigh, repeated if ineffective, oxygen, and crystalloid infusions. Antihistamines and glucocorticosteroids are used to control symptoms and prevent late-phase reactions; they do not replace epinephrine. After stabilization, the patient is observed, educated, and a plan for future action is developed. If a trigger (medication, food, insect venom) is present, further allergy management is performed. [47]

Bradykinin angioedema (hereditary and drug-induced): adrenaline, antihistamines, and glucocorticosteroids are ineffective. First-line drugs include C1 inhibitor concentrate (intravenously), the bradykinin receptor antagonist icatibant (subcutaneously), and, less commonly, the kallikrein inhibitor ecallantide; in the absence of specific agents, fresh frozen plasma may be used. Randomized and registry data confirm a reduction in the time to resolution of edema with the correct choice of these agents. The offending angiotensin-converting enzyme inhibitor must be discontinued immediately and permanently. [48]

Regarding icatibant in drug-induced edema: there is a positive randomized study and contrasting results in another sample, so the decision is individualized based on the severity of edema and the availability of a C1 inhibitor. In any doubt regarding a threat to breathing, the priority is securing the airway. Drug strategies are discussed in parallel with, and not as a substitute for, safe ventilation. [49]

Epiglottitis in adults: If a threat arises, ensure the airway (some patients can avoid intubation with careful observation), initiate empirical intravenous antibiotics against typical pathogens (beta-lactamase inhibitor or third-generation cephalosporin ± metronidazole as indicated), and consider systemic glucocorticosteroids to reduce swelling. In children and with severe symptoms, the threshold for early intubation is low. Repeated painful manipulations without preparedness to protect the airway are contraindicated. [50]

Peritonsillar abscess: The basic approach is drainage (needle or incision) plus antibiotic therapy, analgesia, and rehydration. Empirical regimens cover streptococci, anaerobes, and mixed flora (eg, amoxicillin-clavulanate or penicillin with metronidazole; clindamycin if intolerant). Glucocorticosteroids may accelerate the reduction of pain and swelling. In a subset of carefully selected patients with small abscesses, conservative approaches are being explored, but drainage remains the standard. [51]

Deep phlegmon of the neck: if suspected, urgent CT scan with contrast, early initiation of broad-spectrum antibiotics, and surgical consultation for open or minimally invasive drainage. At any hint of a threat to breathing, airway protection is a priority. Steroids can reduce swelling as part of combination therapy according to individual indications. [52]

Post-intubation and traumatic edema: the key is minimizing trauma, careful intubation technique, selection of the appropriate tube diameter, humidified oxygen, systemic glucocorticosteroids as indicated, and assessment for the need for nebulized epinephrine for stridor. In questionable cases, it is better to temporarily extend observation than to discharge the patient with "recurrent" edema. [53]

Rehabilitation and relapse prevention: for anaphylaxis - education, epinephrine auto-dispenser, written action plan, referral to an allergist. For hereditary angioedema - an emergency treatment plan, training in self-administration of medications, discussion of long-term prophylaxis (subcutaneous or intravenous C1 inhibitor, monoclonal antibody to kallikrein lanadelumab). For drug-induced edema - lifelong abstinence from the offending group. [54]

Table 5. What helps each person with a sore throat (summary)

Scenario	First-line drugs	Note
Anaphylaxis and histamine edema	Adrenaline intramuscularly, oxygen, infusions; antihistamines, glucocorticosteroids as an adjunct	Adrenaline is essential and is administered immediately.
Hereditary and bradykinin edema	C1 inhibitor, icatibant, ecallantide; fresh frozen plasma may be available	Cancelling triggers, training
Epiglottitis	Observation or early airway protection; antibiotics; steroids as indicated	In adults, most cases can be treated without intubation with close observation.
Peritonsillar abscess	Drainage + antibiotics	Steroids can reduce pain and swelling.
Deep neck infections	CT scan, broad-spectrum antibiotics, surgical drainage	The airway is priority number 1.

Prevention

Vaccination against Haemophilus influenzae type B has dramatically reduced the incidence of childhood epiglottitis; maintaining the vaccination schedule remains the best prevention of severe infectious throat swelling. For adults, managing chronic diseases and quitting smoking reduce the risk of severe progression. [55]

Patients with anaphylaxis should avoid known triggers, wear an epinephrine auto-dispenser and be trained in its use; undergo allergy testing and, if necessary, immunotherapy. Family members and colleagues should be aware of the care protocol. [56]

For hereditary angioedema and drug-induced bradykinin edema, consider an emergency treatment plan, access to medications at home and on the go, and avoidance of triggering medications (angiotensin-converting enzyme inhibitors; discuss replacement with your doctor). For patients on long-term prophylaxis, consider regular follow-up visits. [57]

Dental prophylaxis and timely treatment of caries and periodontitis reduce the risk of odontogenic infections and deep phlegmons of the neck. If symptoms of "unusual sore throat" occur, it's better to have an imaging test done sooner rather than later. [58]

Forecast

The outcome depends on the mechanism, speed of recognition, and how quickly the airway is secured. In anaphylaxis, proper administration of epinephrine and observation usually lead to complete recovery without sequelae; mortality in the general population is low. Recurrent episodes are possible without correcting triggers or a plan of action. [59]

In bradykinin-induced edema, outcomes have improved significantly with the availability of targeted drugs, but severe episodes can occur if treatment is delayed. Discontinuation of the offending drugs is critical, as relapses have been reported even after discontinuation of therapy. [60]

Epiglottitis in adults resolves without the need for intubation in most cases with close observation and antibiotic therapy, but in vulnerable groups the risk of complications is higher; timely routing determines the prognosis. [61]

Deep neck infections usually resolve with early imaging, antibiotics, and drainage, but delay can lead to mediastinitis and sepsis. Prognosis improves with a multidisciplinary approach and airway priority.[62]

FAQ

Is it always an allergy?
No. Throat swelling is an umbrella term for many conditions: allergies and anaphylaxis, bradykinin-mediated angioedema, infections (epiglottitis, abscess), trauma, burns. The mechanism determines the treatment. [63]

Why does adrenaline help some people but not others?
Adrenaline is the drug of choice for histamine-mediated edema and anaphylaxis. It is weakly effective for bradykinin-induced edema; a C1 inhibitor, icatibant, and other targeted agents are needed. [64]

Is it always necessary to intubate for epiglottitis in adults?
No. According to current data, the proportion of airway interventions in adults has decreased to approximately 10-11%, but the decision is made individually and with a low threshold for signs of a threat. [65]

Is it true that some medications cause swelling in the throat?
Yes. Angiotensin-converting enzyme inhibitors can provoke bradykinin edema in 0.1-0.7% of patients (in some samples up to 1.6%), especially in the first month of therapy; the risk in people of African descent is 3-5 times higher. [66]

When should you go to the hospital?
Immediately, if you experience noisy breathing, drooling, difficulty swallowing, sudden hoarseness, cyanosis, rapidly changing swelling of the face and tongue, dizziness, or a drop in blood pressure. Better safe than sorry. [67]

Table 6. A reminder for non-specialists: “First steps for a swollen throat”

Step	What to do	For what
1	Assess your breathing: noise, frequency, skin color	Quickly understand if there is a threat
2	If you suspect an allergy, administer adrenaline (if you have an auto-dispenser)	It saves lives in anaphylaxis.
3	Call emergency help, leave the person in a comfortable position	Do not impair cross-country ability
4	Report medications (angiotensin-converting enzyme inhibitors, etc.) and triggers	Helps choose treatment
5	Do not give food or drink if swelling is severe.	To avoid aspiration