QUESTION: My dog started scooting his rear and licking under his tail ever since he went to the groomer for a bath last week. He was only doing it a little before that and was very stinky.

My friend said the groomer could empty his anal sacs when she bathed him and it would stop that. Now I am seeing bloodstains everywhere he lays down. Could the groomer have ruptured something?

ANSWER: Dogs have two little glands on each side of the anal opening just under the skin. They hold a very smelly fluid that is similar to the fluid in a skunk’s scent glands, but not nearly as strong. Dogs sometimes express this fluid when they are nervous or excited. Thankfully most dogs never express this fluid in the house, and tiny amounts trickle out when they have a bowel movement.

The gland can become infected, and an abscess can form. The gland starts to fill with pus and gets swollen. If left untreated, the infection progresses and the area gets painful, hot and very uncomfortable for your dog.

He will lick at the area and rub his rear on the floor, trying to get relief. Emptying the gland can help relieve it temporarily by taking some of the pressure away, but if a bacterial infection is present the gland will just fill with pus again. The gland eventually bursts open like a giant boil.

This can be a serious infection and should be treated by a veterinarian as soon as possible. He will need to have an examination including a rectal exam to check for lumps or cancerous tumors, hernias, fistulas, cysts, or other problems that could be causing the irritation.

He might need the anal glands to be professionally evacuated. Sterile irrigation and infusion of local antibiotics can give much-needed relief and healing. He might also need oral antibiotics, and anti-inflammatory and pain medication.

If left untreated, the gland can continue to form more abscesses and rupture repeatedly, resulting in severe scar tissue and possible fecal incontinence or stricture. The duct for the gland can become scarred and blocked. This could need surgery to repair the damage. Some dogs with severe anal gland problems might need to have the glands surgically removed.

Your groomer did not cause this problem. A gland will abscess and rupture only if it is infected or impacted, or has a tumor growing in it. Most groomers do a great job in preventive emptying out the anal gland externally. This helps to keep dogs clean and make sure that the fluid in the gland doesn’t get dried up and impacted.

If your groomer is unable to express any fluid externally, or notices pain, blood, pus, or lumps, you need to bring him to your veterinarian for a professional internal anal gland expression and examination.

Dr. Susan M. Baker practices veterinary medicine in Palm Beach County, Fla.