Lift the lip on a six-pound Chihuahua and the problem is visible before the dog opens its mouth. Forty-two adult teeth are crowded into a jaw that, on a deer-head Chihuahua, measures only a couple of inches of usable bone. There is not enough room. Plenty of Chihuahuas hit their second birthday already missing teeth, and a fair number develop a small hole between the mouth and the nasal cavity where an infected upper canine root has dissolved the bone above it. That one detail explains more about this breed than any temperament list, because everything else about Chihuahua care — the shivering, the picky eating, the way a simple cough turns serious — runs through a body built at the extreme small end of the canine scale.
What follows is not a list of worst-case scenarios to worry about. It is a map of the handful of problems that show up over and over in Chihuahuas, what they look like in an ordinary living room, and the point at which you stop watching and call the vet.
The mouth is where trouble usually starts
Periodontal disease is the most common diagnosis in small-breed dogs, and the Chihuahua is close to the top of that list. It begins the way it does in people: plaque mineralizes into tartar within two to three days, the gumline reddens, and the tissue pulls away from the tooth. In a mouth this crowded, food packs between teeth that are touching on three sides, and the progression is faster than in a Labrador whose teeth have room to breathe. Owners often notice breath that smells like metal before they notice anything else, then bleeding on a chew toy, then a tooth that has quietly gone loose.
The complication that catches people off guard is what happens at the root rather than the crown. An abscessed upper canine in a small dog can track upward into the nasal passage and leave an oronasal fistula — a direct opening between mouth and nose. You will see one-sided nasal discharge, sneezing that gets worse after the dog eats, or a dog that suddenly dislikes dry food. Fixing it means extracting the tooth and surgically closing the flap, which is a much bigger procedure than the cleaning that would have prevented it.
Two practical things follow from this. First, start home care early and make it boring: a soft-bristled brush and an enzymatic pet toothpaste every day, or at worst every other day, on the outer surfaces where the cheek meets the teeth. Dental chews carrying the Veterinary Oral Health Council seal and chlorhexidine water additives help, but neither reaches below the gumline. Second, budget for cleanings. A routine prophylaxis with pre-anesthetic bloodwork and a couple of extractions typically lands somewhere between $300 and $800 depending on where you live, and a Chihuahua with an established problem may need one annually after age five. Ask your vet to include dental X-rays, because in this breed the damage you can see is usually the smaller half of what is there.
There is also a puppy version of this story. Chihuahuas frequently retain their deciduous canine teeth — the baby tooth stays put while the adult tooth erupts beside it, and the two teeth jam against each other and trap debris. If the baby tooth is still present at six months, it needs to come out, usually during the spay or neuter so the dog only goes under anesthesia once.
That honking cough is not a hairball
If you have ever heard a Chihuahua make the sound owners describe as a goose honk, you know why so many people end up in the exam room convinced their dog is choking. This is tracheal collapse, and it is common enough in the breed that it deserves to be on every owner’s radar. The trachea is held open by C-shaped rings of cartilage; in some small dogs those rings lose rigidity, the membrane across the top of the ring sags, and the tube flattens on inhalation. Vets grade it from one to four, and the cough typically gets louder as the grade climbs.
The triggers are predictable: a collar that pulls against the throat, excitement, cold air, dry indoor heat, dusty rooms, and extra weight pressing on the chest. A dog that coughs when you hook the leash, or when the doorbell rings, or at three in the morning, is telling you something specific. Management is unglamorous but works — switch to a harness, lose the extra pounds, use a humidifier in winter, and keep the dog out of smoky air. When that is not enough, your vet may reach for cough suppressants, bronchodilators, or a short course of steroids, and in advanced cases a veterinary specialist can place a stent inside the trachea to hold it open.
Not every cough is a collapsing trachea, and it is worth learning the difference. A reverse sneeze is a short, snorting fit where the dog stands still with its elbows out and pulls air in through the nose for ten to thirty seconds, then stops as abruptly as it started. It looks terrifying and is almost always harmless. A collapsing trachea cough is dry, harsh, and triggered by pressure or activity. A soft, moist cough that lingers after boarding or a dog-park visit could be infectious. Keep a fifteen-second phone video; that clip is often worth more to your vet than a verbal description.
Blood sugar, body heat, and why size changes the rules
Small bodies have small reserves, and nowhere does that matter more than blood glucose. A Chihuahua puppy who skips a meal, or an adult toy dog under about five pounds who goes twelve hours without eating, can drop into true hypoglycemia. The signs escalate quickly: dullness, glassy stare, a wobbly walk, trembling, then seizures. If your Chihuahua is staring into space and staggering, rub a small amount of corn syrup, maple syrup, or honey on the gums — where it absorbs without needing to be swallowed — and get to a clinic. Most owners who have been through it once keep a tube of glucose gel in the kitchen drawer afterward.
Puppies between roughly eight and sixteen weeks are the highest-risk group, which is why breeders and vets push three or four small meals a day rather than free-feeding a bowl. Many Chihuahuas outgrow the sensitivity as adults, but tiny dogs in the three-to-four-pound range can stay vulnerable, particularly if they are ill or stressed.
Temperature works the same way. A dog with a high surface-area-to-mass ratio loses heat fast, and Chihuahuas start shivering well before a big dog feels anything. Below about 45°F, most of them want a sweater, and the coat should cover the chest and belly rather than just the back. If a Chihuahua gets truly chilled — shivering hard, lethargic, cool ears and paws — that is a slow warm-up with blankets rather than a hot bath, and a call to the vet if the dog does not perk up.
One more item belongs in this section, and it is a breeding issue rather than a daily-care one. Chihuahua puppies have relatively large heads for the birth canal, and planned or emergency Cesarean sections are common in the breed. If you are breeding intentionally, have a plan and the money set aside; a scheduled C-section runs several hundred to well over two thousand dollars depending on timing and whether it happens at two in the morning.
What tends to show up in the middle years
Around middle age, three different problems start competing for attention, and they look nothing alike. The first is luxating patella — a kneecap that slips out of its groove. You will notice it as an intermittent skip: the dog takes two or three three-legged hops on the back leg and then walks normally again. Vets grade it from one to four; low grades are managed with weight control and muscle conditioning, while higher grades usually need surgery, and bilateral repairs can run into the thousands per knee.
The second is heart disease, specifically myxomatous mitral valve disease, where the valve between the left atrium and left ventricle thickens and leaks. Your vet hears it as a murmur, graded one through six, years before the dog shows any sign. This is one more reason to take dental disease seriously, because bacteria from an infected mouth can seed the heart valves.
The third is the one owners misread most often. Chiari-like malformation and syringomyelia are well documented in small breeds including the Chihuahua. The skull is slightly too small for the brain, cerebrospinal fluid flow is disrupted, and fluid pockets can form in the spinal cord. The classic sign is phantom scratching — the dog scratches at the air near its neck or shoulder without making contact, often while walking, and then flinches when you touch that area. Some dogs yelp when picked up under the ribs. Diagnosis requires an MRI, which is a referral-level expense, and treatment ranges from anti-inflammatory medication to surgery.
Underneath all of it sits body weight. Two extra pounds on a six-pound dog is a thirty percent increase, and it loads the knees, the trachea, and the heart at once. Forget the number on the scale for a moment and use your hands: you should be able to feel ribs without pressing hard, and there should be a visible waist when you look down from above.
None of this means your Chihuahua is destined for trouble. It means this breed rewards the owner who looks inside the mouth once a week, uses a harness instead of a collar, keeps meals small and regular, and treats a new cough or a new skip in the step as worth a phone call. Those four habits catch most Chihuahua problems at the stage where they are cheap and easy to fix.