Pathology at the umbilicus can manifest as inflammation, drainage, a palpable mass, or herniation.
Omphalitis - A cellulitis of the umbilicus. Mild cases often respond to local application of alcohol to clean the area, but due to the possibility of rapid progression and abdominal wall necrotizing fasciitis, admission for observation and IV antibiotics is usually warranted. Cover staph, strep, and GNRs.
Umbilical granuloma - As the umbilical ring closes and the cord sloughs off, granulation tissue formation is a normal part of umbilical epithelialization. There is sometimes an overgrowth of granulation tissue which can be treated once or twice with silver nitrate. Should the tissue not regress after a 1-2 treatments, the patient should be referred to pediatric surgery for excision and evaluation of other pathology (urachal or vitelline remnants).
Umbilical fistula - This is a patent vitelline duct and is characterized by persistent drainage that is bilious or purulent. A fistulogram using a small catheter and radio opaque dye can sometimes be helpful in determining the source of drainage (dye should be seen in the small bowel).
Umbilical polyp - Often confused with an umbilical granuloma with its glistening cherry red appearance, this is actually a vitelline duct remnant and contains small bowel mucosa. It does not regress with silver nitrate.
Vesicoumbilical fistula/sinus - The urachal versions of the umbilical fistula. This are a failure of complete closure of the urachus, resulting in persistent drainage of urine from the umbilicus, and infection (including recurrent UTIs). A fistulogram can be helpful for diagnosis.