Perianal and Perirectal Abscess
Perianal abscesses (pus collection) and fistulas (tunnels that connect the inside of the anus to the skin outside) are seen commonly in male infants younger than 1 year of age with a peak incidence at 4 months of age. Histologic examination of removed fistula specimens shows a lining that suggests that there is tissue leading from the anus that is present at birth that causes this problem. The problem is limited to the region just near the anus, in contrast to the perirectal abscesses seen in older children which are deeper. Drainage of the abscess can be performed in the clinic and often relieves pain and accompanying fever. Antibiotic treatment is usually not necessary. Approximately one third of abscesses come back, and approximately one third develop into a fistula. A recurrent abscess or fistula can be treated effectively and simply by placing a probe through the fistula to the anus, where the probe passes through or creates an opening. The overlying skin down to the probe is opened, and the open fistula is cauterized or burned.
Perianal and perirectal abscesses in older children frequently are the first signs of Crohn’s disease, leukemia, or immune disorders, although most are not associated with these diseases. Perianal and perirectal abscesses are associated with fever and pain. Although perianal abscesses are evident on physical inspection, perirectal infections may be evident only on rectal examination. Perianal abscesses should be drained as soon as they are identified. Antibiotics may or may not be required for localized perianal abscesses, but they are always indicated in patients with perirectal disease.
Article and graphics adapted from O'Neill: Principles of Pediatric Surgery. © 2003, Elsevier.