Streptococcal throat infection (Strep throat)

Streptococcal throat infection overview

Streptococcal throat infection is the most common bacterial infection affecting children from 5 to 15 years old, albeit individuals of any age can develop strep throat. Usually the throat infection is caused by the group A streptococci (GAS), though sometimes group C and G streptococci may be the causative agents. GAS may colonize the throat of healthy individuals without causing any symptoms – these asymptomatic carriers of the infection comprise up to 20% of students .

The infection is spread by the droplets of mucus or nasal discharge from an infected person (ill or carrier) and direct close contact is necessary for the bacteria to infect the others.

Risk factors

Streptococcal throat infection

Pediatrician examines sitting child using wooden tongue depressor to check girl’s sore throat

  • Children are especially susceptible to streptococcal infection and are likely to develop the postinfection syndromes like poststreptococcal glomerulonephritis, acute rheumatic fever and rheumatic heart disease;
  • The illness is more likely to develop during the winter and early spring;

Streptococcal throat infection scarlet symptoms

Incubation period, usually lasts from 2 to 4 days. The illness remains symptomatic for several days and may resolve spontaneously, although the bacteria may persist in the throat and nose for many weeks.

The disease starts acutely when a person experiences throat pain, which worsens while swallowing, accompanied by fatigue, fever and headache.

Symptoms of streptococcal infection include:

  • Sore throat, painful while swallowing;
  • General malaise;
  • Fever (higher than 38ºC) and chills;
  • Headache;
  • Other non-specific symptoms like hoarseness, cough, coryza and conjunctivitis are possible, although pretty unlikely in bacterial infection and are rather suggestive of a viral infection;

On the examination the back wall of the pharynx appears red and swollen with enlarged lymphoid follicles, tiny red spots may be observed on the soft and hard palate (palatal petechiae). Tonsils are also enlarged and reddish with purulent patches or while  on their surface.  At the angles of the mandibles enlarged and tender lymph nodes can be palpated (submandibular adenopathy), anterior cervical lymph nodes are also often involved.

However, not everyone experiences all of the symptoms. For example, the disease is milder in those who underwent tonsillectomy (surgical resection of the tonsils) and in infants.

Although pharyngitis itself in general is not a dangerous condition, if untreated, it may eventually lead to severe and even potentially life-threatening disorders like peritonsillar abscess, acute rheumatic fever and streptococcal toxic shock syndrome.

Streptococcal throat infection scarlet fever

Scarlet fever is associated pharyngeal infection, when bacteria start producing erythrogenic toxins (exotoxins). These toxins cause the appearance of diffuse reddish rash on the second day of the disease. The first elements occur on the chest and later spread to the other parts of the trunk, neck and limbs. The rash is usually described as sandpaper. Additionally, red like a strawberry tongue is characteristic for scarlet fever.

Streptococcal throat infection diagnosis

The following tests may be performed to obtain the correct diagnosis:

  • Increased white blood cells (WBCs) count with neutrophilia (high neutrophils number);
  • Rapid strep test is performed to detect Streptococcus antigens from the pharyngeal swabs;
  • Throat culture is considered the gold standard to diagnose Streptococcal infection, although its disadvantage is that it requires a lot of time before the bacteria grow;
  • C-reactive protein levels typically are increased in streptococcal pharyngitis;

Streptococcal throat infection – Treatment

Nonsteroidal anti-inflammatory drugs (NSAIDs) such as paracetamol and ibuprofen may be prescribed to relieve pain and fever.

Bacterial infection should be treated with antibiotics. Despite the fact that the symptoms usually resolve within 3-5 days, antibiotics should be given for at least 10 days. Natural penicillins and their forms remain the mainstay treatment for GAS.

Applicable medicines

  • Benzathine penicillin G 1.2 million units or penicillin V 500 mg per orally twice a day for 10 days. Amoxicillin is an alternative;
  • Erythromycin is recommended for individuals allergic to penicillin;