When topical irritations indicate real problems


Who can resist a basset hound? Those outrageous floppy ears, plaintive eyes, and soft, droopy lips? Holden was just such a pup that I had seen recently for a routine physical and vaccinations. Other than an ear infection, he had been the picture of health, so I was surprised when his owner called, telling my secretary that Holden now had little bumps all over. “Book them this afternoon,” I suggested, knowing my morning was busy. A skin infection could wait a little while.

“I applied a topical flea and tick product this morning,” his mom said, when they arrived later. “The bumps came up right after that.” I hustled into the exam room the moment I laid eyes on him. This wasn’t a skin infection. Holden was covered with hives.

When the body is exposed to certain substances, like bug saliva from a mosquito bite, mast cells in the skin respond by releasing histamine, turning the bite into a red, itchy bump. This is normal. Annoying, but normal. But for some reason, when certain individuals are exposed to certain substances, the immune system freaks out. It overreacts, flooding the whole body with massive amounts of histamine and other chemicals that cause multiple, raised, itchy welts of varying size.

Technically called urticaria, hives can be provoked by many things including food, insect stings, medications, vaccines, environmental factors, and pollen, to name a few. Sometimes the initiating cause cannot be identified. Hives may resolve without treatment, but once in a while they progress to a deeper, more diffuse swelling, called angioedema, which typically affects the face and lips in dogs.

“Do his lips look swollen?” I asked his mom. Who can tell on a basset hound? But we all agreed: his lips were definitely puffier than usual.

Now dogs with swollen faces are common during the summer when curious pooches use their noses to sniff at those interesting bees or wasps, and get stung. Naturally, the face swells, because that’s where the sting occurred. But Holden’s swollen lips were not the result of a localized insect sting. This was a generalized, systemic allergic reaction including hives and angioedema.

If the swelling extended to the throat, it could occlude air flow and be fatal. That’s why people with serious peanut or bee sting allergies carry Epi-pens.

Holden’s angioedema seemed confined to his face and he was breathing easily, but we didn’t want to take any chances. I quickly gave him an injection of antihistamine and started him on oral corticosteroids. Within a few minutes, his lips were back to normal. Even the hives were getting smaller by the time we finished chatting about future precautions to take.

Jolly is another patient of mine, also part hound. Okay, he’s half beagle, half Corgi, but he’s still pretty darn cute. Jolly has never had hives. In fact, other than being overweight, he’s had few medical problems in his life — except one, a chronically irritated butt.

Now I’m always telling my staff, “Use correct medical terminology. Don’t write ‘butt’ on a record.” It’s not professional. It’s ambiguous. What exactly is irritated? The top of his rump where the tail attaches? Or underneath? Where exactly underneath?

Let’s eschew euphemisms. The technically correct term here is anus, and Jolly’s was chronically irritated. Being so pudgy, he had trouble keeping his bottom clean and would frequently scoot on the floor, like dogs with anal glands problems do.

I attributed his recurrent irritation to a combination of poor personal hygiene, anal gland issues, and self-trauma. I treated accordingly, expressing the glands, shaving the area, prescribing varying regimens of topical cleansers and ointments, and sometimes oral antibiotics and anti-inflammatories. Jolly did not take kindly to his mother’s ministrations, so home care was a challenge, but his condition would generally improve — and then recur.

So what does this have to do with Holden and hives, you ask? Good question. Jolly came in again recently. This time his anus was markedly red and inflamed, more than I would have expected since he had none of the usual feces caked to the fur, his glands were fine, and his mother reported no scooting.

If he wasn’t rubbing himself raw, then why was the area so red? In humans there is a condition called pruritus ani, where the area gets itchy and irritated, and it is usually simply treated symptomatically, as we had been doing for Jolly. But what if there was some other underlying cause I had neglected to consider?

Poor little guy, I thought, sitting down at my computer to research further possibilities.

“I found some interesting discussions about similar cases in a number of Corgis that turned out to be food allergies,” I told Jolly’s owner later on the phone.

In dogs, food allergies typically manifest as generalized skin problems, so I hadn’t really considered this diagnosis, but maybe this was an atypical presentation. I had learned that in people, pruritus ani can sometimes be related to certain foods, such as chocolate, tomatoes, or citrus fruits, either due to direct contact irritation or an allergic immune response. Maybe something in Jolly’s diet was causing the problem. We agreed to run basic blood tests, evaluate for food allergies, and start a hypoallergenic diet.

All the laboratory results aren’t in yet, but preliminary tests are supportive of a possible allergy. We have to give him some time to accept the new food, but I am hopeful that the change in diet may provide him with some long-term relief if the underlying cause does turn out to be allergic in nature.

The juxtaposition of the two cases has left me pondering the complexities of the immune system. How it protects us from so many dangers, and yet how a little glitch in normal functioning can cause such a wide range of problems. From a sweet-faced basset hound suddenly and completely covered in hives to a tubby little Corgi mix with a chronically inflamed….well, you know.