You should seek the advice of your veterinarian if your pet is ill as only he or she can correctly advise on the diagnosis and recommend the treatment that is most appropriate for your pet.

Umbilical hernias are very common in puppies, kittens and other young animals

It is quite common to find a small swelling in the midline on the underside of the abdomen where the umbilicus joined an animal when it was a fetus. In humans this site is often called the "bellybutton".  A swelling at this site is usually noticed soon after birth and it can be firm or soft. 

A small, hard, painless swelling is usually of no consequence and may be composed of fibrous tissue or a small amount of fat. Occasionally a hard swelling can be due to a local reaction to infection ...in which case it is usually hot to the touch, painful and the surrounding skin may be reddened. Sometimes pus may be discharging from a sinus if it is infected. Rarely, a hard swelling can be due to trapped abdominal contents.

A soft swelling that can be pushed back into the abdomen, but which pops back out later is due to a hernia. This type of  hernia is the commonest form and it is caused by a hole in the abdominal wall through which abdominal contents fall. Usually it is just a small amount of fat, but if the hole is large enough other structures such as loops of intestine can pass through and this can be very serious if the loop of intestine gets stuck. If abdominal contents get trapped in a hernia the lump cannot be pushed back, so it feels hard not soft, and it can be painful.

Sometimes what starts as a small defect in the abdominal wall can stretch and become larger. This may occur during pregnancy when the abdominal wall muscles are greatly stretched, or if the animal has to strain strongly (as in constipation or blockage of the urinary tract)  So, a small hernia can become bigger.

Fortunately, most small hernias do not need to be treated, but infections requre antibiotic therapy, and middle to large size hernias usually have to be operated on to close off the hole to prevent the likelihood of an abdominal organ getting trapped. Surgical repair is usually successful first time, but occasionally the hernia may recur, particularly if the abdominal muscles are very weak or if the defect is very large. For such cases special implants are sometimes used to close off the hernia.

When abdominal organs get trapped in a hernia the animal is seriously ill and requires emergency treatment because the blood supply can be cut off causing death of the tissues. 

If you notice an umbilical  swelling on your pet get it looked at by your veterinarian who will be able to advise you about whether it needs to be surgically repaired or not. If you pet has a small hernia, check it regularly to make sure that it doesn't get bigger.

Updated October 2013