Perianal strep is a bacterial skin infection affecting the area around the anus. This condition is caused by Streptococcus pyogenes, the same Group A Streptococcus (GAS) bacteria responsible for strep throat. While it is most frequently diagnosed in children between six months and ten years old, adults can also develop this infection. Understanding the specific signs and necessary treatment is important for managing this localized infection.
Symptoms and Clinical Presentation
The most recognizable sign of perianal strep is the appearance of a bright, intensely red rash around the anus. This redness is typically described as sharply demarcated, meaning it has a distinct border separating the infected skin from the healthy surrounding tissue. The affected area may also appear moist, shiny, or peeling, and often extends approximately two centimeters outward from the anal opening.
Patients frequently experience pain when having a bowel movement, which can sometimes lead to stool-holding behavior or constipation, especially in young children. Intense itching is also a common complaint, along with a burning sensation in the area. The inflammation can sometimes cause small breaks in the skin, called anal fissures, which may result in streaks of blood appearing on the stool or toilet paper.
This distinct presentation helps distinguish perianal strep from other common skin issues like candidiasis, diaper rash, or simple anal fissures. Since the infection affects the skin’s deeper layers, it can be characterized as a localized cellulitis. The infection may also spread to the genitals, causing vulvovaginitis in girls or affecting the penis in boys.
Causes and Methods of Transmission
Group A Streptococcus pyogenes is a bacterium that commonly resides in the human throat and on the skin. The primary mechanism of infection is often self-inoculation, which involves the transfer of bacteria from the nose or throat to the perianal region. This typically occurs when a person, especially a child, touches their mouth or nose and then touches or scratches the anal area with unwashed hands.
The infection is highly contagious and can spread among close contacts within a household. Transmission can happen through the fecal-oral route, where microscopic amounts of the bacteria are transferred. Spread also occurs through shared items like bath towels, washcloths, or contaminated bathwater.
The presence of perianal strep is frequently linked to a recent or concurrent strep throat infection in the patient or a family member. Approximately six percent of children with streptococcal pharyngitis are found to have perianal strep as well. Treating all carriers in a family unit is important to stop the cycle of reinfection, as asymptomatic carriers can unknowingly spread the bacteria.
Diagnostic Confirmation and Treatment Protocols
Diagnosis of perianal strep begins with a physical examination of the distinct perianal rash and a review of the patient’s symptoms. To confirm the presence of Group A Streptococcus, a definitive test is required, involving collecting a sample from the affected area. This is typically done using a perianal swab for bacterial culture.
A rapid strep test can also be used on the perianal area, but a negative result should be followed up with a culture to avoid missing an infection. Once the diagnosis is confirmed, treatment requires systemic antibiotics, as topical creams alone are not effective due to the infection’s depth. The most common first-line treatments are oral antibiotics, such as penicillin or amoxicillin.
The standard duration for the antibiotic course is usually 10 to 14 days to ensure complete bacterial eradication. It is important to complete the entire course of medication, even if the symptoms resolve quickly, to prevent recurrence and reduce the risk of complications. For patients with penicillin allergies, alternative antibiotics like cephalosporins or clindamycin may be prescribed.
Adjunctive care can be used primarily for comfort. This may include warm sitz baths to soothe the inflamed tissue or the application of barrier creams, but these measures do not cure the underlying bacterial infection. Topical antibiotics, such as mupirocin, may be used in combination with oral treatment to enhance effectiveness.
Strategies for Preventing Recurrence
Recurrence of perianal strep is common, affecting up to 39 percent of patients, often due to poor hygiene or incomplete initial treatment. Implementing strict hand hygiene is the most effective preventative measure, requiring thorough washing with soap and water after using the bathroom and before eating. Parents should counsel children on avoiding scratching the anal area, which can transfer bacteria and reinfect the skin.
To prevent spread within the family, contaminated household items should not be shared. This includes avoiding the sharing of bath towels and washcloths, and not allowing the infected person to use communal bathwater. Promptly treating all identified infections in the household, including strep throat in siblings or parents, is also important.
If symptoms return after the initial treatment, a prompt medical evaluation is necessary, which often requires another course of antibiotics. In cases of multiple recurrences, healthcare providers may consider culturing family members, even those without symptoms, to identify environmental reservoirs of the bacteria. This comprehensive approach helps interrupt the cycle of infection and maintain long-term resolution.