Viral Pharyngitis - Causes, Symptoms, Diagnosis and Treatment

Introduction:

Pharyngitis is an upper respiratory tract infection that causes inflammation of the mucous membrane of the oropharynx (middle part of the throat behind the oral cavity). It is otherwise called cobblestone throat or sore throat. It usually causes pain, scratchiness in the throat, and difficulty in swallowing. The symptoms vary according to the causative agent and the immune capacity of the affected individual.

What Are the Causes of Pharyngitis?

The infection is most commonly spread by direct person-to-person contact through saliva or nasal secretion. The most common cause of pharyngitis is a viral infection which can be due to rhinovirus, influenza virus, parainfluenza virus, coronavirus, enterovirus, respiratory syncytial virus, cytomegalovirus, human immunodeficiency virus (HIV), adenovirus, influenza virus, Epstein-Barr virus (EBV), herpes simplex virus, or viruses that cause the common cold. This can also be due to a bacterial infection such as Streptococcus pyogenes. The other less common causes include fungal infections and non-infectious causes like allergies, trauma, cancer, acid reflux, medications, and other toxins such as those in smoking. In younger children, the infection is less severe. It rarely presents as acute pharyngitis. There is mucopurulent rhinitis (pus discharge from nose) and low-grade fever.

What Are the Symptoms of Pharyngitis?

The following are symptoms of a viral infection that is different from a bacterial infection which includes:

• Cough.

• Runny nose.

• Hoarseness of voice.

• Conjunctivitis (inflammation of the conjunctiva in the eye).

• Earache and headache.

• In particular, adenovirus causes fever, sore throat, difficulty in swallowing, and conjunctivitis. This is named pharyngoconjunctival fever. It directly invades the pharyngeal mucosa, which is not true in the case of rhinovirus. Rhinovirus causes increased mucous secretion and swelling of the nose's mucous membrane.

• Epstein-Barr virus causes edema (swelling due to excess fluid) and hyperemia (increased blood in the blood vessels) of the tonsils and pharynx, inflammatory exudate (the fluid that leaks out of blood vessels), fatigue, skin rash, and excessive growth of lymphoid tissue in the nasopharynx.

• Acute herpetic pharyngitis (sore throat) is the most common manifestation of the first episode of herpes simplex virus-1 (HSV-1) infection.

• Influenza A virus causes severe pharyngitis and sore throat. It also includes headaches, fever, chills, and dry cough.

• The parainfluenza virus and coronavirus cause common cold-like symptoms.

• The initial manifestation in an HIV-affected individual will include pharyngitis along with fever, sweats, malaise, lethargy, myalgias (muscle pain).

• Enteroviruses cause viral pharyngitis in children. Coxsackievirus causes herpangina (sore throat, difficulty in swallowing, blister-like bumps in the oral cavity), acute lymphonodular pharyngitis (inflammation of the pharynx), hand, foot, and mouth disease (low-grade fever, sores in the mouth, and rashes on the hands and feet).

How to Diagnose Pharyngitis?

The diagnosis and treatment of pharyngitis will depend on the etiology. If the patients give apparent viral symptoms, there is no need for group A streptococcal testing. In situations where the signs are not clear, the clinician can use a rapid antigen detection test (RADT) or throat culture to confirm the bacterial infection. A throat culture is the gold standard diagnostic test. A complete blood test may provide information on the underlying disease.

The total WBC (white blood cell) count may initially be elevated, followed by a decrease to fewer than 5000 cells per microliter after four to seven days of illness in about 50 % of the cases. Atypical lymphocytosis (excess lymphocytes activated to respond to a viral infection) are seen in EBV and CMV (cytomegalovirus) infections. Specific virological diagnosis is unnecessary for practical purposes. Cultures of nasal secretions, serological tests, and polymerase chain reaction techniques can be used for specific virological diagnoses.

What Is the Treatment for Pharyngitis?

Pharyngitis usually resolves within a week. In a few cases, it can be recurring and termed as chronic. Antibiotics are not helpful in cases of pharyngitis caused by viral infections. Symptomatic treatment is needed in such cases. Pain medication and medication to relieve fever such as Acetaminophen is the drug of choice.

Aspirin should not be used in children or adolescents, especially with influenza, because of its association with Reye syndrome. Anesthetic gargles and lozenges such as Benzocaine can be used for symptomatic relief. In case of severe throat pain and difficulty in swallowing, hospitalization for administering fluids for hydration through veins may be necessary.

Amantadine and Rimantadine are approved to treat the influenza A virus but are no longer used due to resistant strains. Hence, antiviral treatment with Oseltamivir or Zanamivir is necessary for patients with a higher risk for influenza complications. It is recommended to start treatment within 48 hours for better results.

Prevention of Pharyngitis:

Pharyngitis is contagious and can be prevented by

1. Avoid contact with the affected individuals.

2. Avoid sharing your personal things.

3. Wash your hands frequently, especially after coughing or sneezing and before eating.

4. Administration of influenza vaccine to high-risk individuals. Amantadine may be used to prevent influenza A during outbreaks.

What Are the Complications of Pharyngitis?

Viral pharyngitis usually resolves within a week without any complications. But rarely, they may end up in a severe condition that includes:

1. The infection spreads from the throat to other nearby parts, for example- ear infection, sinus infection, tonsillar or peritonsillar abscess.

2. Necrotic epiglottis leads to airway obstruction.

3. Liver failure, ruptured spleen, overactive spleen.

4. Encephalitis (inflammation of the brain), pericarditis (swelling of the thin saclike tissue surrounding the heart), and hematologic disorders (disorders associated with blood and blood cells).

5. Pneumonia (inflammation of the air sac in the lungs).

6. Influenza may be complicated by secondary bacterial pneumonia. Pneumococcal pneumonia is the most common, but staphylococcal pneumonia is the most serious.

Conclusion:

The complication rate associated with viral pharyngitis is relatively low, and the prognosis is excellent. Most adults recover in less than a week and the children in less than two weeks. Patients should be educated about the course of infection and reassured that antibiotic therapy is unnecessary. Any fever persisting for more than five days, extreme throat pain, and difficulty in swallowing should prompt a visit to a doctor.