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Streptococcal pharyngitis, also known as strep throat, is an infection of the
back of the throat
back of the throat
including the
tonsils The tonsils are a set of lymphoid organs facing into the aerodigestive tract, which is known as Waldeyer's tonsillar ring and consists of the adenoid tonsil, two tubal tonsils, two palatine tonsil Palatine tonsils, commonly called the tonsils ...

tonsils
caused by ''
group A streptococcus ''Streptococcus pyogenes'' is a species In biology, a species is the basic unit of biological classification, classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest gr ...
'' (GAS). Common symptoms include
fever Fever, also referred to as pyrexia, is defined as having a temperature Temperature ( ) is a physical quantity that expresses hot and cold. It is the manifestation of thermal energy Thermal radiation in visible light can be seen on th ...

fever
,
sore throat Sore throat, also known as throat pain, is pain or irritation of the throat. Sore throat is usually caused by a viral infection or a group A streptococcal infection (GAS) bacterial infection. Other causes include pharyngitis (inflammation of the th ...
, red tonsils (
tonsilitis
tonsilitis
), and enlarged
lymph nodes A lymph node, or lymph gland, is a kidney-shaped Organ (anatomy), organ of the lymphatic system, and the adaptive immune system. A large number of lymph nodes are linked throughout the body by the lymphatic vessels. They are major sites of lymphocy ...
in the neck. A headache, and nausea or vomiting may also occur. Some develop a sandpaper-like rash which is known as
scarlet fever Scarlet fever is a disease resulting from a , also known as ''Streptococcus pyogenes''. The signs and symptoms include a , fever, headaches, , and a characteristic rash. The rash is red and feels like and the tongue may be red and bumpy. It m ...

scarlet fever
. Symptoms typically begin one to three days after exposure and last seven to ten days. Strep throat is spread by
respiratory droplet A respiratory droplet is a small aqueous droplet produced by exhalation, consisting of saliva or mucus and other matter derived from respiratory tract surfaces. Respiratory droplets are produced naturally as a result of breathing, speaking, sne ...
s from an infected person. It may be spread directly or by touching something that has droplets on it and then touching the mouth, nose, or eyes. Some people may carry the bacteria without symptoms. It may also be spread by skin infected with group A strep. The diagnosis is made based on the results of a rapid antigen detection test or in those who have symptoms. Prevention is by and not sharing eating utensils. There is no vaccine for the disease. Treatment with
antibiotic An antibiotic is a type of antimicrobial An antimicrobial is an agent that kills microorganism A microorganism, or microbe,, ''mikros'', "small") and ''organism In biology, an organism () is any organic, life, living system t ...
s is only recommended in those with a confirmed diagnosis. Those infected should stay away from other people until fever is gone and for at least 12 hours after starting treatment. Pain can be treated with
paracetamol Paracetamol, also known as acetaminophen, is a medication used to treat fever and mild to moderate pain. At a standard dose, paracetamol only slightly decreases body temperature; it is inferior to ibuprofen in that respect, and the benefits of ...
(acetaminophen) and
nonsteroidal anti-inflammatory drug Nonsteroidal anti-inflammatory drugs (NSAIDs) are members of a drug class File:Aspirine macro shot.jpg, Uncoated aspirin Tablet (pharmacy), tablets, consisting of about 90% acetylsalicylic acid, along with a minor amount of inert fillers and ...
s (NSAIDS) such as
ibuprofen Ibuprofen is a medication in the nonsteroidal anti-inflammatory drug (NSAID) class that is used for treating pain, fever, and inflammation. This includes dysmenorrhea, painful menstrual periods, migraines, and rheumatoid arthritis. It may also ...

ibuprofen
. Strep throat is a common bacterial infection in children. It is the cause of 15–40% of sore throats among children and 5–15% among adults. Cases are more common in late winter and early spring. Potential complications include
rheumatic fever Rheumatic fever (RF) is an inflammatory disease that can involve the heart The heart is a muscle, muscular Organ (anatomy), organ in most animals, which pumps blood through the blood vessels of the circulatory system. The pumped blood ca ...
and
peritonsillar abscess Peritonsillar abscess (PTA), also known as quinsy, is an accumulation of pus due to an infection behind the tonsil. Symptoms include fever, throat pain, trismus, trouble opening the mouth, and a change to the voice. Pain is usually worse on one si ...
.


Signs and symptoms

The typical signs and symptoms of streptococcal pharyngitis are a
sore throat Sore throat, also known as throat pain, is pain or irritation of the throat. Sore throat is usually caused by a viral infection or a group A streptococcal infection (GAS) bacterial infection. Other causes include pharyngitis (inflammation of the th ...
,
fever Fever, also referred to as pyrexia, is defined as having a temperature Temperature ( ) is a physical quantity that expresses hot and cold. It is the manifestation of thermal energy Thermal radiation in visible light can be seen on th ...

fever
of greater than , tonsillar exudates (
pus Pus is an exudate An exudate is a fluid emitted by an organism through pores or a wound, a process known as exuding or exudation. ''Exudate'' is derived from ''exude'', "to ooze", from the Latin Latin (, or , ) is a classical language ...

pus
on the
tonsils The tonsils are a set of lymphoid organs facing into the aerodigestive tract, which is known as Waldeyer's tonsillar ring and consists of the adenoid tonsil, two tubal tonsils, two palatine tonsil Palatine tonsils, commonly called the tonsils ...

tonsils
), and large
cervical lymph nodes Cervical lymph nodes are lymph nodes found in the neck. Of the 800 lymph nodes in the human body, 300 are in the neck. Cervical lymph nodes are subject to a number of different pathological conditions including neoplasm, tumours, infection and i ...
. Other symptoms include:
headache Headache is the symptom of pain Pain is a distressing feeling often caused by intense or damaging stimuli. The defines pain as "an unpleasant sensory and emotional experience associated with, or resembling that associated with, actual or ...

headache
,
nausea Nausea is a diffuse sensation of unease and discomfort, often perceived as an urge to vomiting, vomit. While not painful, it can be a debilitating symptom if prolonged and has been described as placing discomfort on the chest, upper abdomen, or ...

nausea
and
vomiting Vomiting (also known as emesis and throwing up) is the involuntary, forceful expulsion of the contents of one's stomach The stomach is a muscular, in the of humans and many other animals, including several s. The stomach has a dilat ...

vomiting
,
abdominal pain Abdominal pain, also known as a stomach ache, is a symptom Signs and symptoms are the observed or detectable signs, and experienced symptoms of an illness, injury, or condition. A sign for example may be a higher or lower temperature than ...
,
muscle pain Myalgia (also called muscle pain and muscle ache) is the medical term for muscle Muscle is a soft tissue found in most animals. Muscle cells contain protein Proteins are large biomolecules or macromolecules that are comprised of one or ...
, or a
scarlatiniform rash Scarlet fever is a disease resulting from a group A streptococcal infection, group A streptococcus (group A strep) infection, also known as ''Streptococcus pyogenes''. The signs and symptoms include a sore throat, fever, headaches, lymphadenopa ...
or
palatal petechiae A petechia (pl. petechiae) is a small (1–2 mm) red or purple spot on the skin or conjunctiva, caused by a minor bleed from broken capillary blood vessels. The word is derived from Latin 'petigo', meaning ‘scab' or 'eruption’. ''Petechia ...
, the latter being an uncommon but highly finding. Symptoms typically begin one to three days after exposure and last seven to ten days. Strep throat is unlikely when any of the symptoms of , hoarseness, runny nose, or mouth ulcers are present. It is also unlikely when there is no fever. File:StrepAug2010.JPG, Mouth wide open showing the throat
A throat infection which on culture tested positive for group A streptococcus. Note the large tonsils with white
exudate An exudate is a fluid emitted by an organism through pores or a wound, a process known as exuding or exudation. ''Exudate'' is derived from ''exude'', "to ooze", from the Latin Latin (, or , ) is a classical language A classical lang ...
. File:Streptococcal pharyngitis.jpg, Mouth wide open showing the throat
Note the
petechiae A petechia (pl. petechiae) is a small (1–2 mm) red or purple spot on the skin or conjunctiva The conjunctiva is a tissue Tissue may refer to: Biology * Tissue (biology), an ensemble of similar cells that together carry out a specific f ...
, or small red spots, on the
soft palate The soft palate (also known as the velum, palatal velum, or muscular palate) is, in mammal Mammals (from Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was origin ...
. This is an uncommon but highly finding in streptococcal pharyngitis. File:Strep throat2010.JPG, A set of large tonsils in the back of the throat, covered in white exudate.
A culture positive case of streptococcal pharyngitis with typical tonsillar exudate in an 8-year-old.


Cause

Strep throat is caused by group A β-hemolytic ''Streptococcus'' (GAS or ''S. pyogenes''). Humans are the only known natural reservoir for group A streptococcus. Other bacteria such as non–group A β-hemolytic ''streptococci'' and ''
fusobacterium ''Fusobacterium'' is a genus of Anaerobic organism, anaerobic, Gram-negative, non-sporeforming bacteria, similar to ''Bacteroides''. Individual Cell (biology), cells are slender, rod-shaped Bacillus (shape), bacilli with pointed ends. Strains of ' ...
'' may also cause
pharyngitis Pharyngitis is inflammation Inflammation (from la, inflammatio) is part of the complex biological response of body tissues to harmful stimuli, such as pathogen In biology Biology is the natural science that studies life and living o ...

pharyngitis
. It is spread by direct, close contact with an infected person; thus crowding, as may be found in the military and schools, increases the rate of transmission. Dried bacteria in dust are not infectious, although moist bacteria on toothbrushes or similar items can persist for up to fifteen days. Contaminated food can result in outbreaks, but this is rare. Of children with no signs or symptoms, 12% carry GAS in their pharynx, and, after treatment, approximately 15% of those remain positive, and are true "carriers".


Diagnosis

A number of scoring systems exist to help with diagnosis; however, their use is controversial due to insufficient accuracy. The modified
Centor criteria The Centor criteria are a set of criteria which may be used to identify the likelihood of a bacterial infection in adult patients complaining of a sore throat. They were developed as a method to quickly diagnose the presence of Group A streptococc ...
are a set of five criteria; the total score indicates the probability of a streptococcal infection. One point is given for each of the criteria: *Absence of a cough *Swollen and tender cervical lymph nodes *Temperature > *Tonsillar exudate or swelling *Age less than 15 (a point is subtracted if age >44) A score of one may indicate no treatment or culture is needed or it may indicate the need to perform further testing if other high risk factors exist, such as a family member having the disease. The
Infectious Disease Society of America The Infectious Diseases Society of America (IDSA) is a medical association representing physicians, scientists and other health care professionals who specialize in infectious diseases. It was founded in 1963 and is based in Arlington, Virginia. A ...
recommends against routine antibiotic treatment and considers antibiotics only appropriate when given after a positive test. Testing is not needed in children under three as both group A strep and
rheumatic fever Rheumatic fever (RF) is an inflammatory disease that can involve the heart The heart is a muscle, muscular Organ (anatomy), organ in most animals, which pumps blood through the blood vessels of the circulatory system. The pumped blood ca ...
are rare, unless a child has a sibling with the disease.


Laboratory testing

A is the
gold standard A gold standard is a monetary system A monetary system is a system by which a government provides money in a country's economy. Modern monetary systems usually consist of the national treasury, the mint (facility), mint, central bank, the cen ...
for the diagnosis of streptococcal pharyngitis, with a sensitivity of 90–95%. A
rapid strep test The rapid strep test (RST) is a rapid antigen detection test (RADT) that is widely used in clinics to assist in the diagnosis of bacterial pharyngitis Pharyngitis is inflammation Inflammation (from la, inflammatio) is part of the complex ...
(also called rapid antigen detection testing or RADT) may also be used. While the rapid strep test is quicker, it has a lower sensitivity (70%) and statistically equal specificity (98%) as a throat culture. In areas of the world where
rheumatic fever Rheumatic fever (RF) is an inflammatory disease that can involve the heart The heart is a muscle, muscular Organ (anatomy), organ in most animals, which pumps blood through the blood vessels of the circulatory system. The pumped blood ca ...
is uncommon, a negative rapid strep test is sufficient to rule out the disease. A positive throat culture or RADT in association with symptoms establishes a positive diagnosis in those in which the diagnosis is in doubt. In adults, a negative RADT is sufficient to rule out the diagnosis. However, in children a throat culture is recommended to confirm the result. Asymptomatic individuals should not be routinely tested with a throat culture or RADT because a certain percentage of the population persistently "carries" the streptococcal bacteria in their throat without any harmful results.


Differential diagnosis

As the symptoms of streptococcal pharyngitis overlap with other conditions, it can be difficult to make the diagnosis clinically. Coughing, nasal discharge,
diarrhea Diarrhea, also spelled diarrhoea, is the condition of having at least three loose, liquid, or watery defecation, bowel movements each day. It often lasts for a few days and can result in dehydration due to fluid loss. Signs of dehydration of ...
, and in addition to fever and sore throat are more indicative of a viral sore throat than of strep throat. The presence of marked lymph node enlargement along with sore throat, fever, and tonsillar enlargement may also occur in
infectious mononucleosis Infectious mononucleosis (IM, mono), also known as glandular fever, is an infection usually caused by the Epstein–Barr virus The Epstein–Barr virus (EBV), formally called ''Human gammaherpesvirus 4'', is one of the nine known human herpe ...
. Other conditions that may present similarly include
epiglottitis Epiglottitis is the inflammation Inflammation (from la, inflammatio) is part of the complex biological response of body tissues to harmful stimuli, such as pathogen In biology Biology is the natural science that studies life and liv ...

epiglottitis
,
Kawasaki disease Kawasaki disease is a syndrome A syndrome is a set of medical signs and symptoms Signs and symptoms are the observed or detectable signs, and experienced symptoms of an illness, injury, or condition. A sign for example may be a higher or l ...
, acute retroviral syndrome,
Lemierre's syndrome Lemierre's syndrome refers to infectious thrombophlebitis of the internal jugular vein. It most often develops as a complication of a bacterial pharyngitis, sore throat infection in young, otherwise healthy adults. The thrombophlebitis is a serious ...
,
Ludwig's angina Ludwig's angina (lat.: Angina ludovici) is a type of severe cellulitis involving the floor of the mouth. Early on the floor of the mouth is raised and there is difficulty swallowing saliva, which may run from the person's mouth. As the condition w ...
,
peritonsillar abscess Peritonsillar abscess (PTA), also known as quinsy, is an accumulation of pus due to an infection behind the tonsil. Symptoms include fever, throat pain, trismus, trouble opening the mouth, and a change to the voice. Pain is usually worse on one si ...
, and retropharyngeal abscess.


Prevention

Tonsillectomy Tonsillectomy is a list of surgical procedures, surgical procedure in which both palatine tonsils are fully removed from the back of the throat. The procedure is mainly performed for recurrent tonsillitis, throat infections and obstructive sleep ...
may be a reasonable preventive measure in those with frequent throat infections (more than three a year). However, the benefits are small and episodes typically lessen in time regardless of measures taken. Recurrent episodes of pharyngitis which test positive for GAS may also represent a person who is a chronic carrier of GAS who is getting recurrent viral infections. Treating people who have been exposed but who are without symptoms is not recommended. Treating people who are carriers of GAS is not recommended as the risk of spread and complications is low.


Treatment

Untreated streptococcal pharyngitis usually resolves within a few days. Treatment with antibiotics shortens the duration of the acute illness by about 16 hours. The primary reason for treatment with antibiotics is to reduce the risk of complications such as
rheumatic fever Rheumatic fever (RF) is an inflammatory disease that can involve the heart The heart is a muscle, muscular Organ (anatomy), organ in most animals, which pumps blood through the blood vessels of the circulatory system. The pumped blood ca ...
and retropharyngeal abscesses. Antibiotics prevent acute rheumatic fever if given within 9 days of the onset of symptoms.


Pain medication

Pain medication such as NSAIDs and
paracetamol Paracetamol, also known as acetaminophen, is a medication used to treat fever and mild to moderate pain. At a standard dose, paracetamol only slightly decreases body temperature; it is inferior to ibuprofen in that respect, and the benefits of ...
(acetaminophen) helps in the management of pain associated with strep throat. Viscous
lidocaine Lidocaine, also known as lignocaine and sold under the brand name Xylocaine among others, is a local anesthetic A local anesthetic (LA) is a medication A medication (also called medicament, medicine, pharmaceutical drug, medicinal drug o ...

lidocaine
may also be useful. While
steroids A steroid is a biologically active organic compound with four rings arranged in a specific molecular configuration. Steroids have two principal biological functions: as important components of cell membranes which alter membrane fluidity; and ...
may help with the pain, they are not routinely recommended. Aspirin may be used in adults but is not recommended in children due to the risk of
Reye syndrome Reye syndrome is a rapidly worsening brain disease Central nervous system diseases, also known as central nervous system disorders, are a group of neurological disorder A neurological disorder is any disorder of the nervous system In B ...
.


Antibiotics

The antibiotic of choice in the United States for streptococcal pharyngitis is
penicillin V Phenoxymethylpenicillin, also known as penicillin V (PcV) and penicillin VK, is an antibiotic useful for the treatment of a number of bacterial infections. Specifically it is used for the treatment of strep throat, otitis media, and cellulitis. It ...
, due to safety, cost, and effectiveness.
Amoxicillin Amoxicillin is an antibiotic An antibiotic is a type of antimicrobial An antimicrobial is an agent that kills microorganism A microorganism, or microbe,, ''mikros'', "small") and ''organism In biology, an organism () is ...

Amoxicillin
is preferred in Europe. In India, where the risk of rheumatic fever is higher, intramuscular G is the first choice for treatment. Appropriate antibiotics decrease the average 3–5 day duration of symptoms by about one day, and also reduce contagiousness. They are primarily prescribed to reduce rare complications such as
rheumatic fever Rheumatic fever (RF) is an inflammatory disease that can involve the heart The heart is a muscle, muscular Organ (anatomy), organ in most animals, which pumps blood through the blood vessels of the circulatory system. The pumped blood ca ...
and
peritonsillar abscess Peritonsillar abscess (PTA), also known as quinsy, is an accumulation of pus due to an infection behind the tonsil. Symptoms include fever, throat pain, trismus, trouble opening the mouth, and a change to the voice. Pain is usually worse on one si ...
. The arguments in favor of antibiotic treatment should be balanced by the consideration of possible side effects, and it is reasonable to suggest that no antimicrobial treatment be given to healthy adults who have adverse reactions to medication or those at low risk of complications. Antibiotics are prescribed for strep throat at a higher rate than would be expected from how common it is.
Erythromycin Erythromycin is an antibiotic An antibiotic is a type of antimicrobial An antimicrobial is an agent that kills microorganism A microorganism, or microbe,, ''mikros'', "small") and ''organism In biology, an organism () i ...

Erythromycin
and other
macrolides The macrolides are a class of natural product A natural product is a chemical compound A chemical compound is a chemical substance composed of many identical molecules (or molecular entity, molecular entities) composed of atoms from more ...
or
clindamycin Clindamycin is an antibiotic An antibiotic is a type of antimicrobial An antimicrobial is an agent that kills microorganism A microorganism, or microbe,, ''mikros'', "small") and ''organism In biology, an organism () is ...

clindamycin
are recommended for people with severe penicillin allergies. First-generation
cephalosporins The cephalosporins (sg. ) are a class of β-lactam antibiotics originally derived from the fungus A fungus (plural: fungi or funguses) is any member of the group of Eukaryote, eukaryotic organisms that includes microorganisms such as yeast ...
may be used in those with less severe allergies and some low certainty evidence suggest cephalosporins are superior to penicillin. These late-generation antibiotics show a similar effect when prescribed for 3–7 days in comparison to the standard 10-days of penicillin when used in areas of low rheumatic heart disease. Streptococcal infections may also lead to acute glomerulonephritis; however, the incidence of this side effect is not reduced by the use of antibiotics.


Prognosis

The symptoms of strep throat usually improve within three to five days, irrespective of treatment. Treatment with antibiotics reduces the risk of complications and transmission; children may return to school 24 hours after antibiotics are administered. The risk of complications in adults is low. In children, acute rheumatic fever is rare in most of the developed world. It is, however, the leading cause of acquired heart disease in India, sub-Saharan Africa, and some parts of Australia.


Complications

Complications arising from streptococcal throat infections include: *
Acute rheumatic fever Rheumatic fever (RF) is an inflammation#Inflammatory disorders, inflammatory disease that can involve the heart, joints, skin, and brain. The disease typically develops two to four weeks after a Streptococcal pharyngitis, streptococcal throat inf ...
*
Scarlet fever Scarlet fever is a disease resulting from a group A streptococcus (group A strep) infection, also known as ''Streptococcus pyogenes''. The signs and symptoms include a sore throat Sore throat, also known as throat pain, is pain or irritation ...

Scarlet fever
* Streptococcal toxic shock syndrome *
Glomerulonephritis Glomerulonephritis (GN) is a term used to refer to several kidney The kidneys are two reddish-brown bean-shaped organs An organ is a group of tissues with similar functions. Plant life and animal life rely on many organs that co-exist ...
* PANDAS syndrome *
Peritonsillar abscess Peritonsillar abscess (PTA), also known as quinsy, is an accumulation of pus Pus is an exudate An exudate is a fluid emitted by an organism through pores or a wound, a process known as exuding or exudation. ''Exudate'' is derived from ' ...
*
Cervical lymphadenitis Cervical lymphadenopathy refers to lymphadenopathy of the cervical lymph nodes (the glands in the neck). The term ''lymphadenopathy'' strictly speaking refers to disease of the lymph nodes, though it is often used to describe the enlargement of the ...
*
Mastoiditis Mastoiditis is the result of an infection that extends to the air cells of the skull The skull is a bone A bone is a Stiffness, rigid tissue (anatomy), tissue that constitutes part of the vertebrate skeleton in animals. Bones protect the ...
The economic cost of the disease in the United States in children is approximately $350 million annually.


Epidemiology

Pharyngitis Pharyngitis is inflammation Inflammation (from la, inflammatio) is part of the complex biological response of body tissues to harmful stimuli, such as pathogen In biology Biology is the natural science that studies life and living o ...

Pharyngitis
, the broader category into which Streptococcal pharyngitis falls, is diagnosed in 11 million people annually in the United States. It is the cause of 15–40% of sore throats among children and 5–15% in adults. Cases usually occur in late winter and early spring.


References


External links

{{DEFAULTSORT:Streptococcal Pharyngitis Acute upper respiratory infections Human throat Wikipedia medicine articles ready to translate (full) Wikipedia emergency medicine articles ready to translate Streptococcal infections