Group A streptococcal infection
Organism: Streptococcus pyogenesThe group A streptococcus bacteriumresponsiblemost casesstreptococcal illness. Other types (B, C, D,G) may also cause infection. Group B streptococci cause most streptococcal infectionsnewbornsmaternal post-labor/delivery infections.
Some ofmajor syndromes associatedgroup A strep infection are:
- streptococcal pharyngitis or "strep throat"
- scarlet fever, most often preceded bysore throat
- skin infections (impetigo, cellulitis/erysipelas)
- focal infections, limited toparticular body site, e.g., pneumonia, septic arthritis
- bacteremia, sepsis, streptococcal toxic shock syndrome
- necrotizing fasciitis
- complicationsstreptococcal infections, acute rheumatic feverpoststreptococcal glomerulonephritis
Strep throat
SignsSymptoms
The signssymptomsstrep throatred, sore throatwhite patches on tonsils, swollen lymph nodesneck, fever,headache. Nausea, vomiting,abdominal pain more commonchildren.
Transmission
The illnesscaused bybacterium Streptococcus pyogenesis spread by direct, close contactpatients via respiratory droplets (coughing or sneezing). Casual contact rarely resultstransmission. Rarely, contaminated food, especially milkmilk products, can resultoutbreaks. Untreated patientsmost infectious2-3 weeks after onsetinfection. Incubation period,period after exposurebefore symptoms show up,2-4 days. Patientno longer infectious within 24 hrs. after treatment begins.
Diagnosis
Throatswabbedculture or forrapid strep test (10-20 minutes) which can be done indoctor's office. Ifrapid testnegative,follow-up culture (which takes 24-48 hrs.) may be performed. A negative culture suggestsviral infection,which case antibiotic treatment should be withheld or discontinued.
Treatment
Antibiotic treatment will reduce symptoms, minimize spread (transmission),reducelikelihoodcomplications. Treatment consistspenicillin (oral drug10 days; or single intramuscular injectionpenicillin G). Erythromycinrecommendedpenicillin-allergic patients. Second-line antibiotics include amoxicillin, clindamycin,oral cephalosporins. Although symptoms subside within 4 days even without treatment, itvery importantcompletefull courseantibioticsprevent complications.
Scarlet fever (Scarlatina)
Scarlet fever isstreptococcal infection that occurs most oftenassociation withsore throatrarelyimpetigo or other streptococcal infections. Itcharacterized by sore throat, fever andrash overupper body that may spreadcover almostentire body.
SignsSymptoms: Personsscarlet fever havecharacteristic rash thatfine, red, rough-texturedblanches upon pressure. Scarlet fever also producesbright red tongue"strawberry" appearance. The skin often "desquamates," or peels, after recovery, usually on tipsfingerstoes.
Transmission
The illnessspread bysame means as strep throat.
Treatment
Other thanoccurrence ofrash,treatmentcoursescarlet feverno different from thoseany strep throat.
Superficial streptococcal skin infections
Impetigo
Impetigo issuperficial skin infection most common among children age 2-6 years. Skin infectionsusually caused by different streptococci strains than those that cause strep throat.
SignsSymptoms
One or more pimple-like lesion surrounded by reddened skin. Lesions fillpus, then break down over 4-6 daysformthick crust. Impetigooften associatedinsect bites, cuts,other formstrauma toskin. Itchingcommon. Scratching may spreadlesions.
Transmission
The infectionspread by direct contactlesions ornasal carriers. The incubation period1-3 days. Dried streptococci inairnot infectiousintact skin.
Diagnosis''
The diagnosismade based ontypical appearance ofskin lesion.
Treatment
Topical or oral antibioticsusually prescribed.
Cellulitis/Erysipelas
This illness resultsinflammationskinunderlying tissues.
SignsSymptoms
The skinpainful, red,tender. Patients experience feverchills. Lymph nodes may be swollen. The skin may blisterthen scab over. Perianal cellulitis may also occuritchingpainful bowel movements. The erysipelas rash may occur on face, arms, or legshas raised borders. The infection may recur, causing chronic swellingextremities (lymphadenitis).
Transmission
Cellulitis beginsminor trauma, such asbruise, usuallyan extremity.
Diagnosis
The organism may be cultured from skin lesions or recovered from blood.
Treatment
Depending onseverity, treatment involves either oral or intravenous antibiotics.
Severe streptococcal infections
Some strainsgroup A streptococci (GAS) cause severe infection. Those at greatest risk include childrenchickenpox; personssuppressed immune systems; burn victims; elderly personscellulitis, diabetes, blood vessel disease, or cancer;persons taking steroid treatments or chemotherapy. Intravenous drug users alsoat high risk. Severe GAS disease may also occurhealthy personsno known risk factors. All severe GAS infections may leadshock, multisystem organ failure,death. Early recognitiontreatmentcritical. Diagnostic tests include blood countsurinalysis as well as culturesblood or fluid fromwound site. Antibioticschoice include penicillin, erythromycin,clindamycin.
Bacteremia
An invasionbacteria intobloodstream. Once inbloodstream,infection can spreadother partsbody, producing abscesses, peritonitis (inflammationabdominal cavity), endocarditis (inflammation ofheart), or meningitis. Bacteremia may leadsepsis or shock, causingsystemic illnesshigh fever, blood coagulation (thickening)eventually organ failure.Focal infectionsor without bacteremia
GAS can cause focal infections, whichlimited toparticular site. These include pneumonia, abscesstissues neartonsils, joint infections (septic arthritis), bone infections (osteomyelitis), peritonitis,meningitis. Bacteremia can be associatedthese infections, but itnot always present. Treatment depends onspecific clinical findings.Toxic shock syndrome
Streptococcal toxic shock syndrome beginsflu-like symptoms (fever, chills,muscle aches). Paincommon, usuallyan extremity, sometimes inabdomen or chest. The condition progressesconfusioncoma. Blood pressure drops, kidneys malfunction,soft tissues may be infected. The sourcestreptococcus, when identified,most oftensite ofminor wound or bruise. The syndrome occurs most oftenhealthy adults betweenages20-50.Necrotizing fasciitis
Complicationsgroup A streptococcal infections
Acute rheumatic fever (ARF) iscomplication ofstrep throat caused by particular strainsGAS. Although commondeveloping countries, ARFrare inUnited States,small isolated outbreaks reported only occasionally. Itmost common among children between 5-15 yearsage. A family historyARF may predispose an individual todisease. Symptoms typically occur 18 days after an untreated strep throat. An acute attack lasts approximately 3 months. The most common clinical finding ismigratory arthritis involving multiple joints. The most serious complicationcarditis, or heart inflammation (rheumatic heart disease), as this may leadchronic heart diseasedisability or death years after an attack. Less common findings include bumps or nodules underskin (usually overspine or other bony areas) andred expanding rash ontrunkextremities that recurs over weeksmonths. Because ofdifferent ways ARF presents itself,disease may be difficultdiagnose. A neurological disorder, chorea, can occur months after an initial attack, causing jerky involuntary movements, muscle weakness, slurred speech,personality changes. Initial episodesARF as well as recurrences can be prevented by treatmentappropriate antibiotics.
Post streptococcal glomerulonephritis (PSGN)an uncommon complicationeitherstrep throat orstreptococcal skin infection. SymptomsPSGN develop within 10 days followingstrep throat or 3 weeks followingGAS skin infection. PSGN involves inflammation ofkidney. Symptoms include pale skin, lethargy, lossappetite, headachedull back pain. Clinical findings may include dark-colored urine, swellingdifferent parts ofbody (edema),high blood pressure. TreatmentPSGN consistssupportive care.
The original textthis articletaken fromNIH Fact Sheet "Group A Streptococcal Infections", dated March 1999. Aswork ofU.S. Federal Government without any other copyright notice, thisassumedbepublic domain resource.
