A hemorrhoid is a swollen vein structure in the anal canal or under the skin around the anus, similar to a varicose vein. They are classified as either internal, forming inside the rectum, or external, developing under the perianal skin. While hemorrhoids are not infections themselves, they can become infected in rare circumstances. This usually happens only after a complication compromises the tissue’s integrity, allowing bacteria from the gut to invade the damaged site.
Specific Conditions That Increase Infection Risk
The most common ways a hemorrhoid leads to infection involve a disruption of blood flow or a breach of the skin barrier. A complicated hemorrhoid creates an environment where the body’s natural defenses cannot function effectively. When blood flow is restricted, the delivery of white blood cells and other immune components is severely reduced, making the tissue vulnerable to the dense bacterial population of the anal region.
A thrombosed hemorrhoid contains a blood clot (thrombus) and can sometimes lead to infection. The clot causes swelling and severe pain. If the overlying skin breaks down, it creates an open wound that provides a direct entry point for bacteria into the compromised tissue. If an infection takes hold, it can quickly develop into a painful perianal abscess, which is a collection of pus.
A strangulated hemorrhoid substantially increases infection risk. This occurs when prolapsed internal hemorrhoids slip outside the anus and the sphincter muscles trap the tissue, cutting off its blood supply (ischemia). Without oxygen, the tissue begins to die (necrosis), greatly increasing the risk of bacterial invasion and systemic infection. This loss of healthy tissue is a medical emergency as it provides a large, compromised surface for infection to spread.
In addition to mechanical complications, certain factors increase the general risk once the tissue is compromised. Poor local hygiene introduces more bacteria to the wound site. Underlying health conditions, such as diabetes or a weakened immune system, also reduce the body’s ability to fight off infection. Although rare, infections can sometimes develop following procedures like rubber band ligation, where the sloughing tissue is exposed to bacteria before the wound heals.
Identifying Signs of a Hemorrhoidal Infection
Differentiating a simple hemorrhoid flare-up from a genuine infection requires recognizing specific changes in symptoms. An uncomplicated thrombosed hemorrhoid causes severe pain that peaks within 48 to 72 hours and then gradually improves, usually without systemic symptoms. Conversely, an infection often presents with signs that the issue is affecting the entire body.
Systemic symptoms are a major indicator that an infection is spreading beyond the local area. These include the sudden onset of fever and chills, along with generalized malaise. These signs are rarely associated with a non-infected hemorrhoid and suggest the body is mounting a larger immune response to a bacterial invasion.
Localized symptoms also become much more severe and distinct when an infection is present. The pain changes from a severe ache to a throbbing, constant pain that steadily worsens over several days, rather than improving. The area around the hemorrhoid will show intense redness and warmth, and the swelling may continue to grow.
The appearance of pus or foul-smelling discharge is a definitive sign of infection and potential abscess formation. While hemorrhoids can bleed (typically bright red blood), pus is a thick, cloudy, or yellowish fluid that indicates a collection of white blood cells fighting a localized bacterial infection. An anorectal abscess, often a complication of an infected hemorrhoid, presents as a painful, tender, warm lump near the anus. This lump may feel softer or fluid-filled than a typical, firm thrombosed hemorrhoid.
Necessary Steps for Severe Symptoms
When symptoms suggest a complicated or infected hemorrhoid, self-treatment should stop immediately, and professional medical attention is necessary. Any sign of systemic illness, such as a high fever, severe chills, or confusion, requires an immediate visit to an emergency room. These symptoms can indicate a serious, widespread infection like sepsis, which is a life-threatening condition.
Even without fever, severe, unrelenting pain lasting longer than three days suggests a complication. A hemorrhoid turning black, purple, or gray suggests strangulated or necrotic tissue. These conditions require urgent assessment to prevent tissue death and subsequent infection. An inability to pass urine or uncontrollable bleeding also constitutes an immediate medical emergency.
A suspected anorectal abscess, characterized by throbbing pain and a visible, tender lump, requires prompt care. The standard medical treatment is surgical drainage, where a small incision releases the pus and relieves pressure. Antibiotics may be prescribed if the infection is extensive or if the patient has compromised immunity. Ignoring an abscess significantly increases the risk of it developing into an anal fistula, an abnormal tunnel requiring complex surgical repair.