Abscess & Fistulas - Symptoms & Diagnosis
What causes fistulas?
Most anorectal fistulas arise from infected anal crypt glands, while those in Crohn’s disease result from penetrating inflammation rather than gland infection. Patients typically have nonhealing abscesses or chronic purulent drainage, along with pustule-like lesions in the buttock or perianal area. Anorectal fistulas are classified based on their relationship to the anal sphincter, including superficial, intersphincteric, transsphincteric, suprasphincteric, and extrasphincteric types as shown in the diagram. Simple or complex fistulas can occur.