Group A Streptococcus (GAS) is a common bacterium responsible for strep throat, an infection typically associated with school-aged children and teenagers. While classic strep throat (pharyngitis) is rare in infants under one year old, the bacteria can still cause illness. Caregivers should understand that GAS infection is possible in babies, but it often manifests differently than the familiar sore throat. Recognizing the subtle signs of GAS infection in infants is important for ensuring prompt treatment and preventing potential complications.
Understanding Strep in the Youngest Patients
Classic strep throat is uncommon in infants due to factors like maternal antibodies, which offer protection in the first few months of life. Infants also have limited exposure to contagious respiratory droplets from older children, who are the primary carriers. Strep throat is especially rare in children under the age of three.
When Group A Streptococcus affects infants, it frequently presents as an infection of the skin or other areas rather than the throat. Manifestations include impetigo (Streptococcal Pyoderma), which causes itchy, red, sometimes oozing sores that develop a yellowish crust. Another form is perianal streptococcal dermatitis, an infection around the anus and rectum causing a bright red rash. This localized infection may lead to symptoms like pain, itching, or blood-streaked stools.
These non-pharyngeal infections are often caused by the same bacteria and require antibiotic treatment. GAS can also cause streptococcal rhinitis, a persistent, thick nasal discharge. Systemic infections are possible but extremely rare, meaning the typical adult presentation of strep is not the main concern.
Observable Signs and Symptoms in Infants
Since infants cannot verbalize a painful throat, signs of a GAS infection are often behavioral and physical. Caregivers should watch for increased irritability and inconsolable fussiness. A consistent fever lasting longer than 24 hours is also a symptom warranting attention.
Feeding issues are another strong indicator, presenting as a refusal to feed or poor intake, which can quickly lead to dehydration. Physical signs include thick, persistent nasal discharge or a fine, red, sandpaper-like rash on the torso and extremities, suggesting scarlet fever caused by a bacterial toxin.
If the infection is perianal, the bright red rash around the anus might be accompanied by pain during bowel movements. Any significant change in alertness, such as lethargy, or signs of dehydration (e.g., lack of wet diapers for six or more hours) should prompt an immediate call to a pediatrician.
Diagnosis, Treatment, and Serious Risks
Diagnosing GAS infection in an infant involves a medical evaluation and testing, which may differ depending on the suspected site of infection. For suspected throat infection, a throat swab (rapid test or culture) is performed, though experts often do not routinely test children under three due to low complication risk. If skin or perianal infection is suspected, the affected area is swabbed for a culture to identify GAS.
If the test confirms a GAS infection, the standard course of treatment involves oral antibiotics. The entire course of antibiotics (e.g., amoxicillin or penicillin) must be completed as prescribed, even if symptoms improve quickly, to ensure the bacteria is fully eradicated. Treatment typically lasts about 10 days and leads to rapid recovery.
While rare, untreated GAS infections carry the risk of serious complications, known as post-streptococcal sequelae. Concerns include the formation of local abscesses, particularly with skin infections. Acute rheumatic fever, which can damage the heart and joints, is a historical concern but is extremely rare in children under three. Early diagnosis and the full course of antibiotics are highly effective at preventing these severe outcomes.