Acute and chronic paraproctitis. Dermoid cyst (pilonidal cyst)
PERIANAL ABSCESS / ACUTE PARAPROCTITIS
Paraproctitis refers to infection and inflammation in the tissues around the anal canal and rectum. Most anorectal abscesses arise from infected anal glands at the dentate line (cryptoglandular origin). Infection spreads into perianal, intersphincteric, ischiorectal/ischioanal or supralevator spaces. Risk factors include Crohn disease, diabetes and immunosuppression.
CLINICAL FEATURES AND DIAGNOSIS
Typical symptoms are constant throbbing anal pain, swelling, tenderness, fever and malaise. Superficial abscess is visible as erythematous fluctuant swelling; deep abscess may cause severe pain with few external signs, urinary retention or systemic illness. Digital rectal examination may be very painful and should not delay treatment. MRI pelvis or endoanal ultrasound is useful for deep, recurrent or complex disease; CT may be used in emergencies.
TREATMENT OF ACUTE ABSCESS
Incision and drainage is the definitive treatment; antibiotics alone are inadequate. Drain promptly, with examination under anaesthesia for deep/complex collections. Antibiotics are added for sepsis, extensive cellulitis, immunosuppression, diabetes or selected cardiac-risk situations. Avoid probing aggressively for a fistula during acute inflammation if the tract is not clearly identified, as this can injure sphincter muscle.
CHRONIC PARAPROCTITIS AND RECURRENT ABSCESS
Persistent infection may form a chronic sinus or fistula-in-ano connecting anal canal/rectum to perianal skin. Recurrent pain, discharge and external openings suggest fistula. Evaluate for Crohn disease, tuberculosis or malignancy when presentation is atypical or recurrent. MRI maps complex tracts and relation to sphincters. Treatment is fistula-specific: fistulotomy for simple low fistula, seton or sphincter-preserving techniques for complex/high tracts.
PILONIDAL (DERMOID) DISEASE
Pilonidal disease is an acquired inflammatory condition of the natal cleft, usually involving hair penetration and a sinus tract; it is not a true congenital dermoid cyst in most cases. It commonly affects young adults with deep cleft, coarse hair, friction and prolonged sitting. Acute abscess causes painful swelling near the sacrococcygeal region; chronic disease causes midline pits and intermittent purulent/bloody discharge. Diagnosis is clinical; exclude anal fistula if the opening is close to the anus.
MANAGEMENT AND COMPLICATIONS
Acute pilonidal abscess requires incision and drainage. Chronic symptomatic sinus may be managed with hair control and hygiene, pit-picking or excision with off-midline closure/flap (e.g. Karydakis or Limberg) for extensive/recurrent disease; midline closure has higher recurrence/wound problems. Complications include recurrence, chronic discharge, wound infection and rarely malignant change in longstanding disease.