What is pharyngitis?
A sore throat, or pharyngitis, can vary in intensity from mild discomfort in the back of the throat, to a dull ache or pain in the throat. Although subjective, the term ‘sore throat‘ is used to indicate any irritation in the throat that may also involve the back of the mouth (oropharynx), nose (nasopharynx), voice box and esophagus (laryngopharynx). There are a number of causes of a sore throat and while infections are considered to be the leading cause, other non-infectious conditions like GERD is now recognized as a major contributing factor to a persistent sore throat, especially a morning sore throat.
Symptoms of Pharyngitis
A number of factors may irritate the mucous membrane lining of the pharynx. This may or may not involve the tonsils. Once the process of inflammation begins, blood flow to the area increases and the tissue lining the throat becomes congested and swollen. This results in the typical signs and symptoms of a sore throat - pain, discomfort upon swallowing and redness of the throat. A fever may be present if the pharyngitis is a result of an infection and hoarseness of the voice is common. Severe hoarseness of even temporary loss of voice is usually associated with laryngitis – inflammation of the larynx.
Common Causes of a Sore Throat
The most common cause of a sore throat is tonsillopharyngitis. This is inflammation of the throat lining and tonsils most often due to a viral infection. It is often associated with acute respiratory tract infections like the common cold and influenza (seasonal flu). The respiratory syncytial virus (RSV) is more likely seen in children. Most cases of bacterial tonsillopharyngitis are a strep throat which is a result of group A streptococcal infection. Infection lower down the respiratory tract, involving the epiglottis (epiglottitis), larynx (laryngitis) and sometimes even the trachea (tracheitis) are also commonly referred to as a sore throat.
Less common causes include :
- Viruses – Epstein-Barr virus (infectious mononucleosis / “kissing disease”), cytomegalovirus (CMV), herpes simplex (HSV) and HIV (human immunodeficiency virus).
- Bacteria – Corynebacterium diptheriae (diptheria), Haemophilus influenzae type b, Streptococcus pneumoniae, Staphylococcus aureus. While diptheria often involves the nasopharynx, the latter three organisms more often cause epiglottitis.
- Fungi – Fungal infections of the throat are almost always seen in immunocompromised patients, especially in HIV positive patients. The most common of these involves the Candida spp and starts in the mouth (oral candidiasis / thrush) and spreads further down the throat.
Reflux pharyngitis is seen with GERD (gastroesophageal reflux disease) where the rising gastric acid cause irritation of the tissue at the back of the throat. The focus on reflux pharyngitis has grown in recent years as a better understanding on the extent of GERD has highlighted this condition a cause of a morning sore throat, which eases during the course of the day. While severe GERD can cause acid to be regurgitated and travel as high up as the throat when upright, in most cases it causes a sore throat when a person is lying down for prolonged periods of time like during sleep. Acute reflux pharygitis is often seen following heavy alcohol consumptions.
Smoke inhalation may not always be obvious but can account for a sudden sore throat following exposure to smoke. Inhalation of toxic gases and air pollution are other causes. Cigarette smoking is a common cause of an acute sore throat, especially in non-smoker. Regular smokers may experience a sore throat after a heavy bout of smoking or as a result of an infection which smokers are more prone to developing.
Post-nasal drip is often linked to an allergic upper respiratory tract reaction and may cause irritation of the throat. It may be seen throughout the year (perennial) or only during seasons like spring (seasonal). A sudden irritation, especially itching of the throat, following the ingestion of certain foods like shellfish and mushrooms may also be associated with an allergic reaction but can result in anaphylaxis which can be life threatening.
A foreign body lodged in the tonsils or throat may often cause a sudden sore throat. Common causes include fish bones, although in children larger foreign objects may be lodged in the respiratory tract. This may cause a partial occlusion and while there will be difficulty in breathing, air intake is not totally compromised. The child may only report a sore throat and there is usually hoarseness or a whispering tone to the voice.
Trauma to the pharynx or adjacent areas may be due to mechanical strain, as is seen with excessive talking or shouting, injury with foreign objects like a toothbrush as part of dental care or even in induced vomiting as is seen in certain types of eating disorders like bulimia.
Prolonged mouth breathing will cause dryness of the mouth and throat which will eventually lead to irritation of these areas. In acute cases, this is often due to nasal congestion.
This may be a chronic condition or only occur suddenly in cases like heavy alcohol consumption. The pressure of air moving and reverberating through the mouth and throat causes irritation of these areas. The sore throat often starts in the morning upon waking and eases during the course of the day. It may sometimes be confused with reflux pharyngitis.