Tobogganing with a smile on their face, whipping around like they’ve been bitten, chewing the tail, licking incessantly – we've all seen the tasteful things they get up to.

Traditionally assumed to mean the dog needed worming, in reality there is often a different explanation.

Several ailments can trigger intense activity around the tail base/ bottom/ back legs.

The two most common are anal gland problems and flea issues.

Dogs (and cats) have two anal glands – one each side of the anus. Their job is to empty onto the faeces, as a scenting mechanism. They are a modification of the skunk and hyaena organs – the skunk fires them at will, and the hyaena deposits deliberately on plants. Giving a dog a massive fright may stimulate mimicry of the skunk... generally, though, the action of defaecation is the usual mechanisim for emptying them out. If they fail to empty properly, inevitably they start to fill up. Once uncomfortably full, the dog attempts to fix the problem by dragging his (or her) bottom across the floor (especially with guests, on a cream carpet). The leaving behind of a fishy streak confirms relief has been achieved... The next stop is usually the vet, to get them emptied.

Reasons for filling include the dog having soft poo that doesn’t squeeze the glands enough, infection in the gland, the opening (duct) of the gland getting blocked, or (rarely, and associated particularly with cocker spaniels and labradors) an anal gland tumour developing.

Some dogs never have a problem, others need human assistance every few weeks. Adding fibre to the diet (or even, for some dogs, bones - caution) can be helpful for a good proportion. Infections can be straightforward to shift, or a total nightmare. Sometimes, infection progresses to abscesses – these can be excruciatingly painful. The more that infections and abscesses occur, the more scarring and reduction of normal function there is. The ultimate tool is to surgically remove the gland. I performed removal, three weeks ago, of a gland that had suffered haemorrhagic (bloody) infections for two years. Incredibly, I found a grass seed inside the gland. The dog is reportedly brighter than she has been in years. Believe it or not, that 1.5cm long seed was not palpable.

Those who chew around their bums or down their back legs/feet may have full anal glands, but it can also be a sign of flea infestation or allergy. With an allergy, the dog only needs a couple of bites from a hitch hiker flea to set off a reaction. At the moment, I am frequently seeing itchy-rump dogs. Many owners do not know that 95 percent of any flea problem is in the house, in the form of eggs and babies. A lady flea can lay 40 eggs per day, and the larvae can survive for a year in the nooks and crannies of a house...

If fleas, anal glands, and worms have been ruled out, and your dog is still beside itself, it is worth considering anitis. An uncommon condition, the name literally means inflamed anus, and this can be observed by a keen-eyed vet peering inside the anus. It can be caused by food allergy – I have seen two of these in 18 years. One was cured by removal of chicken from the diet, and the other by feeding a highly specialised hydrolysed diet.

I promise that the next article will be less gross!

For further advice or information, please contact 124 Vet by calling 282 338 407, or email 124vet@algarvevet.com