Streptococcal pharyngitis

Overview
Streptococcal pharyngitis or streptococcal sore throat (Strep throat AmE), is a form of group A streptococcal infection that affects the pharynx, and possibly the larynx and tonsils.

Signs and symptoms
Streptococcal pharyngitis usually appears suddenly with a severe sore throat that may make talking or swallowing painful. In severe cases, breathing may be impaired.

Symptoms may include:
 * Sudden and severe sore throat
 * Red and enlarged tonsils
 * Yellow and white patches in the throat.
 * Difficulty swallowing
 * Tender cervical lymphadenopathy
 * Fever of 38°C (101°F) or greater.
 * General discomfort, feeling ill or uneasy
 * Cough or dry cough
 * Halitosis
 * Abdominal pain, nausea and vomiting
 * Rash
 * Hives

Diagnosis
There are several causes for pharyngitis, not just streptococcus bacteria. Productive coughing, nasal discharge, and red, irriated eyes in addition to fever and sore throat are more indicative of a viral sore throat than of strep throat, though a co-infection with a virus is possible and may explain the presence of these additional symptoms. A Rapid Strep Test or a throat culture may be undertaken to help clarify diagnosis.

The presence of marked lymph node enlargement along with sore throat, fever and tonsillar enlargement may also occur in infectious mononucleosis (glandular fever).

A study of 729 patients with pharyngitis in which 17% had a positive throat culture for group A streptococcus, identified the following four best predictors of streptococcus:
 * Lack of cough
 * Swollen and tender anterior cervical lymph nodes
 * (Marked) tonsillar exudates
 * Fever
 * {| class="wikitable"

!Number of symptoms!!Probability of GAS
 * 0||2.5%
 * 1||6.0 - 6.9%
 * 2||14.1 – 16.6%
 * 3||30.1 – 34.1%
 * 4||55.7%
 * }
 * 3||30.1 – 34.1%
 * 4||55.7%
 * }
 * 4||55.7%
 * }

Another study on 621 patients, assigned one point for each of the following symptoms:
 * Temperature greater than 38 C
 * Absence of cough
 * Tender anterior cervical adenopathy
 * Tonsillar swelling or exudate
 * Age younger than 15
 * Subtracting a point for age older than 45.
 * {| class="wikitable"

!Points!!Probability of GAS || Management
 * 1 or less || 0% || Negative: No antibiotic
 * 2        || 17% || rowspan="2" | Indeterminate: antibiotic based on throat culture
 * 3        || 35%
 * 4 or 5   || 51% || Positive: for throat culture and antibiotics
 * }
 * 3        || 35%
 * 4 or 5   || 51% || Positive: for throat culture and antibiotics
 * }
 * }

Finally, patients usually experience swelling of the tonsils and lymph nodes in the neck, but swelling can also be located in the soft palate in the top of the mouth. The absence of tender anterior cervical lymph nodes, tonsillar enlargement, and tonsillar or pharyngeal exudates has been suggested as being the most useful finding in ruling out strep throat; with a negative likelihood of 0.74.

Transmission
Strep throat is caused by Group A streptococcal infection (GAS),   specifically the bacterium Streptococcus pyogenes. It is spread by direct, close contact with an infected person via air-based germs. In addition it may be spread through contamination of pillow cases, toys, tooth brushes, and other often-used materials. Rarely, contaminated food, especially milk and milk products, can result in outbreaks.

The incubation period for strep throat is thought to be between two to five days, but has been reported as long as eight days.

Symptomatic therapies
Nonprescription over the counter drugs of ibuprofen and paracetamol (acetaminophen) both help relieve throat pain and reduce fever by an average of 2.2˚F or 2.3˚F in children. Aspirin is not recommended for children due to the small but fatal risk of Reye's syndrome. In adults aspirin, paracetamol, or ibuprofen help reduce back pain by 48% and sore throat by 31%.

Antibiotics
Antibiotics will reduce symptoms slightly, as was the case in one study of 11 adult patients with sore throat and confirmed GAS infection. They were evaluated daily after the start of antibiotic treatment to register symptoms and signs and to measure body temperature. The mean reduction rate was great, but it was the greatest reduction after 2 days. Out of all symptoms scores was for muscle or joint pain, 86%, and the lowest for sore throat, 67%. Treatment, which consists of penicillin (orally for 10 days or a single intramuscular injection of penicillin G), will also minimize transmission. This is why GAS positive children should not go back to school or day care until they have taken antibiotics for at least 24 hours. In one study, they assessed the potential risk of transmission to close school contact by taking 47 children with positive throat cultures and randomly selecting them to receive penicillin V, penicillin G, or erythromycin. Throat cultures were then taken 24 hours after start of antibiotics and 17 (36.2%) had positive throat cultures and 39 (83%) of the patients became culture negative.

Cephalosporins, such as cefazoline, cefuroxime, and ceftriaxone, are recommended for penicillin-allergic patients. In a study 41 patients, with confirmed penicillin allergy, were evaluated with cefazoline, cefuroxime, and ceftriaxone, all cephalosporins, to see the allergic reaction. Skin tests with cephalosporins were clearly negative in 39 patients and all 41 patients tolerated the three cephalosporins administered.

Second-line antibiotics include amoxicillin, clindamycin, and oral cephalosporins which have a significantly better cure rate than penicillin.

Studies have also shown that the broader-spectrum of antibiotics offer effective short treatment courses that the traditional 10 days of Penicillin V, but noted that "widespread use of broad-spectrum agents for a common infection is a significant concern in an age of increasing bacterial antibiotic resistance".

It is important to complete the full course of antibiotics to prevent rheumatic fever or an abscess on the tonsils. In one report of 500 patients 30% had group A beta-hemolytic streptococcal pharyngitis 0.2% had rheumatic fever and 0.2% had peritonsillar abscess (an abscess on the tonsils).

Other
A 2003 study found extract of Pelargonium sidoides was superior compared to placebo for the treatment of acute non-GABHS tonsillopharyngitis in children. Treatment with EPs 7630 reduced the severity of symptoms and shortened the duration of illness by at least 2 days.

Complications
The symptoms of strep throat usually improve even without treatment in five days, but the patient is contagious for several weeks. Lack of treatment or incomplete treatment of strep throat can lead to various complications. Some of them may pose serious health risks. Therefore, streptococcal tonsillitis is important to recognize and treat early.

Infectious complications

 * The active infection may occur in the throat, skin, and in blood.
 * Skin and soft tissues may become infected, resulting in redness, pain, and swelling. Skin and deep tissues may also become necrotic (rare).
 * Herpes
 * Scarlet fever is caused by toxins released by the bacteria.
 * Rarely, some strains may cause a severe illness in which blood pressure is reduced and lung injury and kidney failure may occur (toxic shock syndrome).

Noninfective complications

 * During the infection, antibodies (disease–fighting chemicals) are produced, sometimes causing a rare complication that can result after the organism is cleared, when these antibodies cause disease in body organs.
 * Rheumatic fever is a heart disease in which the inflammation of heart muscle and scarring of heart valves can occur.
 * Glomerulonephritis is a kidney disease which may lead to kidney failure.