Epidemiology

Accurate figures regarding acute laryngitis are not available, as the condition often goes unreported. The Royal College of General Practitioners reported an average incidence of 6.6 cases of laryngitis and tracheitis per 100,000 patients (all ages) per week in 2010.^[5]

Chronic laryngitis is a complex condition which is similarly under-reported and often goes unrecognised. One series reported an average age at presentation of 45 years and an equal incidence of men and women. There is a 2:1 incidence of men versus women, although the differential is thought to be decreasing due to the increase in women smoking. The typical presenting patient is an adult, in the sixth decade of life.^[2]

Presentation^[1][2]

Symptoms

Acute laryngitis:

• Hoarseness.
• Symptoms of upper respiratory tract infection (cough, rhinitis, fever).
• Odynophonia (pain on speaking), dysphagia, odynophagia (pain on swallowing).
• Dyspnoea.
• Fatigue and malaise.

Chronic laryngitis:
By definition, any patient with symptoms of acute laryngitis persisting for longer than three weeks should be deemed to have chronic laryngitis. In such patients, the following additional information should be sought:

• Personal history:
  • Duration of symptoms, any relieving or aggravating factors.
  • Symptoms suggestive of ill health - lung cancer, thyroid disease.
  • Occupational history, especially exposure to irritant substances or temperature change.
  • Voice abuse.
  • Symptoms suggestive of gastro-oesophageal reflux disease (GORD) - eg heartburn, chest pain, otalgia, cough, wheezing, globus, throat clearing.^[6]
  • History of asthma - this can sometimes be confused with vocal cord dysfunction; history is of throat rather than chest discomfort, often with additional atypical symptoms (voice difficulty, laryngeal stridor, wheeze worse in inspiration).
  • History of allergy.
  • Immunocompromised patients - consider candidal involvement.
• Medication history:
  • Medications causing local drying, mucosal injury - antihistamines, decongestants, diuretics, antihypertensives, psychotropic drugs, inhaled steroids^[7] (don't forget to ask about over-the-counter medicines).
  • Drugs increasing the tendency to develop GORD by decreasing the tone of the lower oesophageal sphincter - calcium-channel blockers, nitrates, beta-blockers, progesterone.
  • Immunosuppressant therapy - consider candida.
  • Inhalation treatments - thermal baths.
• Surgical history:
  • History of intubation - recurrent laryngeal damage, particularly likely in thoracic and abdominal surgery.
  • Surgery leading to anatomical alterations predisposing to GORD (again, thoracic and abdominal).
• Neck trauma.
• Ingestion of caustic substances.
• Travel history (for the possibility of parasitical infections).
• Family history:
  • Autoimmune diseases (eg amyloidosis, systemic lupus erythematosus, Wegener's granulomatosis, rheumatoid arthritis).
  • Similar condition in other family members - consider exposure to environmental pollutants.
  • Contagious disease, eg tuberculosis.
• Social history:
  • Smoking, recreational abuse, alcohol intake.
  • Lifestyle increasing the risk of infectious disease (eg sexually unsafe practices, history of syphilis).
  • Diet - consumption of foods likely to lower oesophageal tone and increase the likelihood of GORD (eg chocolate, caffeine).

Examination

Unless the clinician is experienced in the technique of indirect laryngoscopy (indirect examination of the larynx, using a laryngeal mirror), examination in the limited context of primary care is generally unhelpful, other than to exclude other conditions such as pharyngitis. Patients whose symptoms persist for more than three weeks should have indirect laryngoscopy.

Aetiology^[1][2]

Acute laryngitis

• Infection:
  • Rhinoviruses.
  • Parainfluenza viruses.
  • Respiratory syncytial virus.
  • Adenoviruses.
  • Influenza viruses.
  • Measles virus.
  • Mumps virus.
  • Bordetella pertussis.
  • Varicella-zoster virus.
• Any cause of chronic pharyngitis.

Chronic laryngitis

In addition to the factors outlined above (see 'history' headings under 'Presentation', above), the following should be considered:

• Infection:
  • Bacterial - Staphylococcus aureus (the most common), followed by Haemophilus influenzae and pneumococcal species.
  • Tuberculosis.
  • Leprosy.
  • Syphilis - usually occurs in the second and third stages.
  • Rhinoscleroma - caused by the Gram-negative rod Klebsiella rhinoscleromatis.
  • Actinomycosis.
  • Viruses - play a minor role.
  • Fungal infections - common, especially in immunocompromised patients, and patients taking inhaled steroids.
  • Blastomycosis and histoplasmosis.
  • Leishmaniasis and sporotrichosis.
• Lymphoma of the larynx

Differential diagnosis^[1][2]

Acute laryngitis

• Early chronic laryngitis.
• Reflux laryngitis.
• Spasmodic dysphonia.

Chronic laryngitis

• Chondronecrosis of the larynx.
• Contact granulomas.
• Glottic stenosis.
• Iatrogenic vocal fold scar.
• Subglottic stenosis in adults.
• Sulcus vocalis.
• Vascular lesions of the vocal fold.
• Vocal fold cysts.
• Idiopathic ulcerative laryngitis (prolonged ulceration of the mid-membranous vocal folds, cause unknown).^[8]

Investigations

Acute laryngitis^[1]

• Investigations are rarely helpful in primary care. A swab for microbiological analysis may be contributory if excessive exudate is present.
• Clinicians with the skill to perform indirect laryngoscopy will typically find redness and small dilated vasculature on the inflamed vocal folds.

Chronic laryngitis^[2]

• Laboratory tests:
  • FBC with differential to exclude infection.
  • Sputum culture for bacteria, fungi and viruses.
  • Laryngeal mucosal swab for microbiological analysis.
  • Serology for autoimmune markers.
  • Tests for syphilis and tuberculosis if clinically indicated.^[9]
• Radiology:
  • Lateral X-ray of the neck - may show supraglottic or retropharyngeal swelling, or soft tissue density in subglottic airway.
  • Chest radiograph.
  • CT and MRI scanning may be appropriate if detailed morphology of the larynx is required.
  • Barium swallow study, double-contrast upper gastrointestinal series and manometry - may be required to exclude gastro-oesophageal reflux disease (GORD).
  • Videostrobe - unit consists of a stroboscopic unit (light source and microphone), a video camera, an endoscope and a video recorder, useful in diagnosing vocal cysts, polyps and nodules.^[10]

Associated diseases^[1]

Acute laryngitis

• Measles.
• Mumps.
• Chickenpox.
• Herpes simplex virus.^[11]

Chronic laryngitis

• Gastro-oesophageal reflux disease (GORD).
• Infections - viral, bacterial, fungal, mycoplasmal.
• Chronic rhinitis (allergic and non-allergic).^[12]
• Autoimmune disease.
• Pellagra.^[13]

Management

Acute laryngitis^[1]

• Most cases are mild and self-limiting.
• Nondrug measures found to be helpful include inhaling humidified air and minimal use of the voice.
• Inhaling humidified air promotes moisture of the upper airway, helping to clear secretions and exudate.
• Use of antihistamines and corticosteroids is not supported by evidence. Indeed these treatments may cause temporary respite leading to overuse of the voice, as well as drying of the larynx.
• Antibiotics have a limited place in the initial management of acute laryngitis. A Cochrane review found no difference in clinical outcome in adult patients given penicillin V compared with placebo. Erythromycin promoted some benefit in terms of voice improvement but this was not thought to be clinically signficant.^[14]
• Antibiotics may be helpful in patients who have persistent symptoms or who have other problems such as immune system deficiency.
• Acute laryngitis is unusual in children under the age of 18. Failure to respond to symptomatic relief should raise the possibility of other conditions, such as tracheobronchitis, especially if there are other features such as dyspnoea.

Chronic laryngitis^[2]

• Supportive measures - these include hydration (approximately 2 litres per day), steam inhalation, avoidance of pollutants and cigarette smoke and avoidance or limitation of exposure to environmental or occupational sensitisers.
• Treat the underlying condition - eg gastro-oesophageal reflux disease (GORD) may need appropriate lifestyle advice, prokinetic drugs and proton pump inhibitors.
• Staphylococcus aureus is a common secondary infection and appropriate antibiotic therapy may be helpful. Initial therapy for suspected chronic bacterial infection should cover both aerobic and anaerobic organisms, eg co-amoxiclav.
• Hospital admission - be prepared to arrange hospital admission if the patient develops stridor, becomes systemically unwell, or is at risk of food aspiration.
• Surgery - the following may be contributory:
  • Surgical relief of stenosis.
  • Laser vaporisation.
  • Laparoscopic reflux surgery.

Complications^[1][2]

• Acute laryngitis - complications are rare, as the disease is usually self-limiting. Damage to the vocal cords is possible in patients who try to overcompensate for the dysphonia.
• Chronic laryngitis - the main complications are voice loss, obstruction of the airways and chronic cough. Spread of infection to surrounding tissues and laryngeal stenosis, can occur with prolonged disease. Rarely, systemic spread may occur. An association with laryngeal carcinoma remains unproven.

Prognosis

In acute laryngitis, the prognosis is usually excellent.^[1] With chronic laryngitis the prognosis depends on the underlying condition.^[2]

Prevention

There are no particular preventive measures for acute laryngitis, although avoidance of irritant factors such as cigarette smoke may be helpful.^[1] In chronic laryngitis:^[2]

• Irritant factors should be avoided - especially active or passive smoking.
• Patients on inhaled steroids should be advised regarding appropriate use, eg dose reduction, twice-daily dosing, mouth rinsing and use of spacers.
• Speech therapy may be necessary in cases of voice abuse.
• Lifestyle advice should be given to patients at risk of gastro-oesophageal reflux disease (GORD).