Most common cause of anorectal abscess is –
**Core Concept**
Anorectal abscesses are a type of anal fistula or perianal infection caused by a bacterial overgrowth. The most common cause is a blocked gland in the anal canal, specifically the apocrine gland, which leads to a localized infection.
**Why the Correct Answer is Right**
The correct answer is an infection of the apocrine gland in the anal canal, which results in an anorectal abscess. This is often due to a blockage of the gland's duct, allowing bacteria to accumulate and cause an infection. The apocrine gland is a type of sweat gland found in the anal canal, and its blockage can lead to a range of symptoms, including pain, swelling, and discharge.
**Why Each Wrong Option is Incorrect**
* **Option A:** While _E. coli_ is a common cause of bacterial infections, it is not the primary cause of anorectal abscesses.
* **Option B:** _Staphylococcus aureus_ can cause skin infections, but it is not the most common cause of anorectal abscesses.
* **Option C:** While anal fissures can cause pain and discomfort, they are not a direct cause of anorectal abscesses.
**Clinical Pearl / High-Yield Fact**
Anorectal abscesses often present with a painful, swollen area in the perianal region, and may be accompanied by discharge or bleeding. It is essential to diagnose and treat anorectal abscesses promptly to prevent complications, such as anal fistulas or perianal infections.
**Correct Answer:** D.