From the Guidelines
Perianal abscesses in a 30-year-old male are typically caused by infection of the anal glands, which can become blocked and subsequently infected, with the most common causative organisms being gut flora, particularly Escherichia coli, Bacteroides species, and other anaerobic bacteria 1.
Causes and Risk Factors
The causes of perianal abscesses include:
- Infection of the anal glands
- Local trauma to the anal area
- Poor hygiene
- Anal intercourse
- Inflammatory bowel disease (especially Crohn's disease)
- Diabetes mellitus
- Obesity
- Immunocompromised state
- Constipation or diarrhea, which can cause small tears in the anal lining
- Foreign bodies, ingested objects like fish bones, or sexually transmitted infections
Diagnosis and Treatment
Diagnosis is typically made through a focused medical history and complete physical examination, including a digital rectal examination 1. Treatment typically involves surgical incision and drainage under local or general anesthesia, followed by antibiotics if there are signs of surrounding cellulitis or the patient is immunocompromised 1. Common antibiotic regimens include amoxicillin-clavulanate 875/125 mg twice daily for 7-10 days or ciprofloxacin 500 mg twice daily plus metronidazole 500 mg three times daily for 7-10 days 1. Sitz baths 2-3 times daily and regular cleaning of the area are important for healing.
Recurrence and Underlying Conditions
Recurrent perianal abscesses may indicate an underlying fistula or chronic condition requiring further investigation 1. It is essential to exclude the presence of undiagnosed underlying Crohn's disease in every patient presenting with an anorectal abscess, especially if recurrent 1.
Management Approach
The management of perianal abscesses should prioritize source control, which may involve surgical incision and drainage, and antibiotic therapy if necessary 1. The goal of surgical therapy is to drain the abscess expeditiously, identify a fistula tract, and either proceed with primary fistulotomy to prevent recurrence or place a draining seton for future consideration 1.
From the Research
Causes of Perianal Abscess
- A perianal abscess can be caused by a variety of factors, including bacterial infections, with studies indicating that drug-resistant bacteria are frequently found in perianal abscesses 2.
- The bacteriology of perianal abscesses is complex, with species such as Escherichia coli, Bacteroides, Streptococcus, and Staphylococcus being commonly detected, often with acquired drug resistances 2.
- Comorbidities, such as inflammatory bowel disease (IBD), diabetes, or malignancy, can increase the risk of developing a perianal abscess or fistula 3.
- Other factors, such as smoking, may also contribute to the development of fistula in-ano after incision and drainage of a perianal abscess 4.
Role of Antibiotics
- The use of antibiotics, such as ciprofloxacin and metronidazole, may play a role in preventing fistula in-ano formation after incision and drainage of a perianal abscess 4.
- A randomized single-blind clinical trial found that postoperative antibiotic therapy, including ciprofloxacin and metronidazole, significantly reduced the rate of fistula formation compared to standard care without antibiotics 4.
- However, the effectiveness of antibiotics in treating perianal fistulas in patients with Crohn's disease is less clear, with a pilot study finding no significant difference in remission rates between ciprofloxacin, metronidazole, and placebo 5.
Patient Characteristics
- Perianal abscesses can occur in patients of any age, but the mean age of patients in one study was 43 years old, with 73% being male 3.
- Patients with certain comorbidities, such as IBD, diabetes, or malignancy, may be at increased risk of developing a perianal abscess or fistula 3.
- Male sex has been identified as a risk factor for developing fistula in-ano after incision and drainage of a perianal abscess 4.