Perianal abscess is the medical term of the swelling, which occurs secondary to collection of pus (inflammatory material) in and around anus. The condition develops between muscle planes and soft tissues surrounding the anus.
Normally, anal glands ensures lubrication during defecation and humidifies skin, and those glands are located between circular muscle fibers, which avoid involuntary gas and feces discharge. This region is rich in bacterial colonies and such organisms invade glands, resulting with abscess formations. This condition is usually misunderstood as hemorrhoid.
Underlying cause of perianal abscess is not clear in 90% of cases. In other words, a foreign body or solid feces injures glands and facilitates invasion of bacteria, resulting with abscess formation. This mechanism is referred as abscess formation secondary to non-specific factors. The second mechanism is referred as abscess formation secondary to specific factors. This group accounts for only 10 % of perianal abscesses. Specific factors include but not limited to Crohn's disease, ulcerative colitis, lymphoma, radiotherapy and cancers. Most patients consider if the condition is related with hygiene. There is no direct link with hygiene.
Symptoms can be divided into two groups. Common abscess or findings of infection: fever, fatigue, malaise, tiredness and weakness. As shown in Figure 1, this two groups of symptoms may lead to extra findings and symptoms depending on localization. If abscess is superficial, one may experience swelling, redness, warmth and pain. If it has deeper localization, one may feel sensation of pressure, stasis or discharge during defecation. Inflammation (collection of purulent material) is almost always manifested as rapidly progressing pain, which leads to discomfort when patient sits. It is a cause of admittance to emergency room at night. Throbbing, severe pain, perianal warmth, fever, shivering and fainting can be also seen. Perianal redness and swelling will be remarkable when it fistulizes to skin.+
Anorectal abscess should be considered if patient is complaining about anal pain, swelling, fever and tiredness. Anamnesis, or medical history of the patient, should be primarily questioned, when any diagnosis is made. Second approach should be physical examination. Non-complicated and superficial abscess can be diagnosed with inspection. Rectal digital examination is of diagnostic value, if it is localized at deeper layers. However, rectal ultrasonography, computerized tomography or MRI may be sometimes required. particularly if abscess is frequently relapsing or new abscess formations develop at various zones of perianal region.
Obesity, long-term (chronic) constipation, presence of hemorrhoid and fistula and some inflammatory intestinal diseases (ulcerative colitis, Crohn's disease) and conditions suppressing immune system increase risk of perianal abscess
Treatment of abscess is surgery and pus (inflammatory material) should be immediately drained or emptied and if necessary, patient is started on antibiotherapy. The principle of surgery is to make incision on the skin covering the abscess formation. Purulent material can be easily drained using this incision. Significant complications of perianal abscess include recurrence and perianal fistula formation or development.