Anal Fissure
Bleeding from underneath a sentinel pile is called an anal fissure. The sentinel pile (sentinel skin tag) is a characteristic physical finding located just distal to the fissure itself, marking the site of this painful condition 1.
Anatomical Relationship
A sentinel skin tag is an associated physical finding that sits just distal to an anal fissure, with the fissure being a split in the squamous epithelium at or just inside the anal verge 1.
The sentinel tag represents a sign of chronicity in anal fissures, along with hypertrophied anal papilla at the proximal margin, fibrosis, and visualization of bare internal sphincter muscle at the fissure base 1.
The bleeding originates from the fissure itself (the split in the epithelium), not from the sentinel pile, though the pile marks the location of the underlying pathology 1.
Clinical Presentation
Bleeding from anal fissures is characteristically bright red and scanty, typically occurring during and after defecation 1.
The main symptoms include severe anal pain that occurs during and after defecation, with chronic fissure patients experiencing pain lasting many hours after bowel movements 1.
The diagnosis should be suspected based on history alone, with patients offering a standard presentation pattern 1.
Diagnostic Confirmation
Fissures are best visualized by effacing the anal canal with opposing traction on the buttocks, allowing direct visualization of the split in the squamous epithelium 1.
The great majority of anal fissures occur in the midline, usually posteriorly 1.
If fissures occur off the midline, they mandate evaluation for underlying diagnoses such as Crohn's disease, HIV/AIDS, ulcerative colitis, tuberculosis, syphilis, leukemia, or cancer 1.
Clinical Significance of Sentinel Piles
The presence of a sentinel pile adversely affects treatment outcomes, with fissures being significantly less likely to heal initially, more likely to recur, and more likely to remain unhealed long-term when a sentinel pile is present 2.
Sentinel piles are observed in approximately 30% of patients with chronic anal fissures 2.
Up to 20% of patients with hemorrhoids have concomitant anal fissures, which can complicate the clinical picture 3, 4.
Common Pitfall
- Do not confuse the sentinel pile itself as the source of bleeding—the bleeding originates from the fissure (the epithelial split) that lies just proximal to the sentinel tag 1.