Streptococcal Pharyngitis

Streptococcal pharyngitis, also known as strep throat, is a bacterial infection caused by Streptococcus pyogenes, also referred to as Group A beta-hemolytic streptococcus (GABHS). It is one of the most common bacterial infections affecting the throat.

Cause and Transmission

The bacteria that cause streptococcal pharyngitis are highly contagious and can be spread through:

• Direct contact with an infected person's respiratory secretions, such as through kissing or sharing utensils
• Indirect contact with contaminated surfaces or objects
• Droplet transmission, where the bacteria are released into the air when an infected person coughs or sneezes

Symptoms

The symptoms of streptococcal pharyngitis typically develop within 2-5 days after exposure to the bacteria and may include:

• Sudden onset of a sore throat, which can be severe and is often accompanied by pain when swallowing
• Fever, usually high (over 101°F)
• Swollen, tender lymph nodes in the neck
• White or yellowish patches on the tonsils
• Red, swollen tonsils and throat
• Headache
• Stomachache
• Nausea and vomiting, especially in children

Diagnosis

Diagnosing streptococcal pharyngitis involves a combination of physical examination, medical history, and laboratory tests. The most common diagnostic tools include:

• Rapid streptococcal antigen test (RSA), which provides quick results but may not always be accurate
• Throat culture, which is more sensitive than RSA but takes longer to produce results (usually 24-48 hours)
• PCR (polymerase chain reaction) testing, a molecular diagnostic technique that can quickly and accurately identify the presence of GABHS DNA in throat swabs

Treatment

The primary treatment for streptococcal pharyngitis is antibiotics. The most commonly prescribed antibiotics are:

• Penicillin (such as amoxicillin or penicillin V)
• Amoxicillin-clavulanate
• Cephalexin or other cephalosporins, for individuals allergic to penicillin
• Azithromycin or clarithromycin, in cases of penicillin allergy and for patients who cannot tolerate cephalosporins

It is essential to complete the full course of antibiotics as prescribed by a healthcare provider, even if symptoms improve before finishing the medication. This helps prevent complications and reduces the risk of spreading the infection to others.

Complications

If left untreated or inadequately treated, streptococcal pharyngitis can lead to several complications, including:

• Acute rheumatic fever (ARF), a serious condition that can affect the heart, joints, skin, and brain
• Post-streptococcal glomerulonephritis (PSGN), an inflammatory disease of the kidneys
• Peritonsillar abscess, a collection of pus behind the tonsils that can cause severe pain and difficulty swallowing
• Mastoiditis, an infection of the mastoid bone in the skull
• Sinusitis, an infection of the sinuses
• Otitis media, an infection of the middle ear

Prevention

To reduce the risk of contracting streptococcal pharyngitis:

• Practice good hygiene by washing hands frequently with soap and water
• Avoid close contact with individuals who have a sore throat or are known to be infected
• Do not share utensils, glasses, or other personal items
• Cover the mouth and nose when coughing or sneezing
• Stay home from work or school if symptoms persist or worsen over time