David was surprised when three weeks ago, his two dogs started to itch. Their coats have always been in optimal condition, and they’ve never suffered from any skin issues.
They both started scratching their undersides, and when David got them to roll on their backs, their bellies had a reddish, pink colour, like somebody with mild sunburn. They also had sore areas on the lower parts of their legs. David wondered if they had walked over some sort of irritating vegetation, such as nettles or a toxic plant of some kind, but there was nothing obvious around.
The itchiness didn’t go away, so tried keeping them off grass, and put them on a “low allergy” diet. He couldn’t see any fleas, but he put a “spot on” herbal product from the pet shop on the back of their necks. The dogs continued to itch, so he brought him to see me.
My job was simple: find out the cause of the itch. When two dogs, living together, start to itch at the same time, a physical cause in the environment is likely. Common causes that make individual dogs itch, like allergies, are less likely.
I asked David if he’d been using a new type of floor cleaner, or if they had new bedding, or a new detergent for their bedding, but there was nothing obvious.
The distribution of the itchy areas – their undersides and lower legs – was a clue to the cause. I used a scalpel blade to collect some skin scrapings from the affected patches, and looked at them under the microscope. The first skin scrapes were negative, but then I found what I was looking for: a tiny mite, called Sarcoptes Scabei, the cause of Sarcoptic Mange. This is so small that it can only be seen under the microscope, and it causes intense itchiness by burrowing into the skin, feeding on skin cells. It isn’t easy to find: it’s only seen in 20% of skin scrapes from affected dogs.
Sarcoptic Mange is infectious, spreading from dog to dog, and also being passed on in bedding from one dog to another. One of David’s dogs must have had contact with a dog with mange, and the mites had then easily passed on to his other pet.
Now that we know what the cause was, treatment was simple. I applied a vial of a potent anti-mite drug to the back of each dog’s neck, to be repeated in a month. I asked David to put all their bedding through an ultra-hot wash, and to thoroughly clean their living area. I also gave the dogs anti-inflammatory tablets to ease the itchiness for the first few days, until the mites had all gone.
Two days later, the dogs had stopped itching: when that mite is killed, mange gets better.