Attishooh! Pets often sneeze, just like people
LAST week, I discussed the topic of dogs sniffing, and their remarkable sense of smell. This week, the focus is on something closely related to this: sneezing.
Sneezing happens across all species, from humans, to dogs and cats, to rabbits and rats, to just about any creature you can think of. Mammals, birds and reptiles all sneeze.
Sneezing is a way of clearing the respiratory tract of dust, mucus and other obstructions.
It’s a reflex, largely beyond conscious control, triggered by nasal irritation. Animals like fish and insects, that have different breathing mechanisms (such as gills, spiracles or other ways of obtaining oxygen) may not sneeze, but they have an equivalent type of reaction. Oxygen is essential to the continuation of life, and every form of life needs to have a way of clearing the flow of oxygen if it becomes blocked in any way.
Animals (and humans) cannot sneeze when they are asleep. If there was enough sneeze-stimulating stuff in the air (e.g. a cloud of dust), the animal would be woken up by the irritation first, and only then would they sneeze.
The type of irritation that prompts a sneeze varies: small particles of dust or debris settling on the inner lining of the nose are a common cause, but there’s a long list of other possibilities, including irritant vapours, allergies, viruses, tiny nasal parasites called nasal mites, and strangely perhaps, a sudden drop in temperature, or exposure to bright light.
A sneeze starts with a slow, steady inhalation, filling the lungs with air. This is followed by a short, sharp exhalation through the nose and mouth.
This sudden burst of air out through the nose is an effective way of forcing out any loose material from the nasal passages. Most often, nothing visible is ejected, but if a substantial amount of mucus, or other material like blood, has gathered inside the nose then this will be expelled as visible droplets.
The burst of air is a powerful force. There was a recent report of a man who tried too hard to suppress his sneeze, by keeping his mouth shut and pinching his nose. He was just trying to be polite, but there was a nasty consequence: the explosion of air could not pass outwards, so it went inwards instead, rupturing an internal airway. He needed emergency surgery to stop the leak. Animals don’t know the meaning of being polite, so they’d never stifle a sneeze, but there is an important message for sneezing humans here: be discreet by all means, but don’t try to stop a sneeze completely.
Even if nothing visible is ejected by a sneeze, up to 100000 microscopic particles are generally sprayed into the atmosphere by a single sneeze, travelling at a speed of up to 100 mph. This makes sneezing a highly effective method of spreading infections. Infectious causes of sneezing are rare in dogs, but common in cats: cat flu, caused by two different viruses, spreads rapidly when cats are enclosed in a confined air space, largely because sneezing cats fill the room with floating viral particles that are then inhaled by other cats.
Sneezes in dogs are most often caused by allergies and sensitivities, and an occasional sneeze is nothing to be worried about. Rarely, sneezing starts to happen with increased frequency, and when this happens, an investigation by the vet is needed. Also, if copious discharges are produced, and in particular, if a bloody discharge is seen at either nostril, it’s important to accurately diagnose the cause of the sneeze.
The first task in such cases is to inspect the nasal passages as carefully as possible. This isn’t easy to do: the nostril is a small opening, and it’s difficult to see the inside of the nose. With a placid animal, the tip of a scope can sometimes be inserted through a nostril, but even then, you can only see so far back. For a detailed inspection, a general anaesthetic is needed, and a long, narrow, flexible endoscope has to be passed into each nostril, pushing it all the way to the back of the throat. If the sneeze is caused by something stuck inside the nose, it can sometimes be identified and removed in this way. A common example is a blade of grass: animals sometimes eat grass, then regurgitate it. It’s easy for a small piece of grass to go the wrong way when it’s brought up, getting snagged in the nasal chambers on the way out.
If a visual inspection cannot find an obvious cause of sneezing, more advanced diagnostic imaging is needed: this starts with x-ray pictures and these days extends to include CAT scans and MRI scans. To go further, biopsy samples may need to be collected from the lining of the nose to find out what’s going on. Rarely, a serious problem such as a tumour or a fungal infection may be diagnosed. More commonly, nothing specific is found, and the condition may be then described as “ideopathic rhinitis” (an irritated nose for a reason that cannot be pinpointed).
Dogs often have a variant of sneezing, called reverse sneezing, when they breathe out slowly through their nose, then inhale sharply, making an explosive snuffling noise. Owners worry about this, but it’s a common benign happening that’s rarely a cause of concern.
Occasional sneezing is a normal, healthy part of being alive. If a pet only sneezes with a similar frequency to yourself, don’t worry. A simple “Bless You” is all that’s required.