What kind of health problems do Chihuahuas have?

Chihuahuas are affected by far fewer genetic defects than other pedigree dog breeds. Below is a list of some of the health problems that you might encounter with your Chihuahua.

Patella Subluxation or “loose kneecaps”

Patellar subluxation is a somewhat common problem in small and large breeds. This condition is also known as “slipped stifles” or “loose kneecaps.” Patellar subluxation is a partial dislocation of the kneecap (the patella). What happens is that the kneecap, on the dog’s rear legs, slips out of its groove, called the trochlea. If your Chihuahua has a mild case of this, then he or she can live a normal life, much like a human being with a “dodgy” knee. However, if your Chihuahua’s kneecaps slip constantly, the only solution may be surgery.

Hypoglycemia or “low blood sugar”

Hypoglycemia is often called “low blood sugar.” If your dog’s body is deprived of sugar (glucose), its primary source of energy, his ability to function declines. It is a common problem in young Chihuahua puppies. The majority of puppies grow out of what’s known as toy breed juvenile hypoglycemia, but, for some, it is something that may affect them their whole lives.

What are the symptoms of hypoglycemia?

  • Extreme lethargy (i.e. sleepiness or unresponsiveness and inactivity)
  • Muscle twitching
  • Loss of appetite
  • Increased hunger
  • Trembling/shivering
  • Incoordination
  • Abnormal behaviour
  • Blindness
  • Unconsciousness

If your Chihuahua does not receive immediate aid, it may lead to seizures, and ultimately, death. Should you suspect your dog is suffering from hypoglycemia, call your vet and go to the clinic as soon as possible.

Low blood sugar is a symptom of an underlying disease or problem, not a disease in itself. 

Why does your Chihuahua suffer from hypoglycemia?

There are many reasons dogs may be suffering from hypoglycemia. For example, puppies, particularly those under three months of age, are still not able to regulate their blood sugar levels. The condition can also occur when other stress factors are introduced into puppies’ lives such as poor diet, the cold, and intestinal parasites. Toy breeds, like the Chihuahua, are particularly susceptible to this condition. Low blood sugar can also be brought on by fasting coupled with hard exercise, as well as Addison’s disease. Dogs diagnosed with diabetes mellitus are at risk, along with dogs that suffer from severe liver disease or pancreatic cancer.

Tracheal collapse

Tracheal collapse also called collapsing trachea, is a genetic disorder and a common problem affecting the windpipes of Chihuahuas and many other toy breeds. The trachea, or windpipe, is a tube made up of rings of cartilage which carries air through the neck to and from the lungs. Occasionally these rings collapse and squeeze the air through the resulting smaller gap in the windpipe, causing the dog to produce a characteristic cough. 

What are the symptoms of Tracheal collapse? 

Signs of Tracheal collapse include coughing, as mentioned above, difficulty in breathing and blueish coloured gums. The coughing and other symptoms may be provoked by irritants such as smoke or dust, hot, humid weather and obesity. 

How is Tracheal collapse treated?

In most cases, tracheal collapse is treated with medicine to suppress the cough and control inflammation. In severe cases, surgery may be the only option.

Congenital Heart Disease

Chihuahuas are known to be susceptible to a condition called Patent Ductus Arteriosis. This condition occurs when the vessel that moves blood between two parts of the heart does not close properly after birth. As a result, too much blood gets carried to the lungs causing fluid build-up, and strain on the heart. The symptoms of this condition are coughing, tiredness during exercise, weight loss, breathlessness and weakness in the back legs. Vets can diagnose this problem by listening for a specific kind of heart murmur with a stethoscope. Your vet may recommend surgery to fix this problem.


A molera is a “hole” or soft spot on top of a Chihuahua’s head. It is called a fontanelle in human infants. In Chihuahuas, the molera is considered to be a characteristic of the breed, and not considered to be a condition or defect. Eighty to ninety per cent of Chihuahuas have a molera. Unlike human babies, however, the molera does not close and the bones knit together. Normally the “hole” narrows as the dog gets older. Your Chihuahua’s molera will not usually be a problem provided that as you are aware of its existence when petting or holding his head.

In rare cases, the molera remains very large and could be a sign of hydrocephalus. 


Chihuahuas are predisposed to congenital hydrocephalus, which is also known as “water on the brain”. In this condition, the fluid normally found in the brain, and spinal cord builds up and causes pressure on the brain. The skull may swell abnormally, and the pressure can cause chronic pain and brain damage. 

What are the signs of hydrocephalus? 

  • Enlarged dome-shaped skull
  • Inability to be housebroken
  • Inability to learn
  • Erratic behaviour
  • Disorientation
  • Lethargy
  • Loss of coordination
  • Compulsive circling
  • Head pressing
  • Blindness
  • Seizures
  • Crossed eyes
  • Unusual gait

Treating hydrocephalus

Unfortunately treating the disease is complicated and expensive, and in the later stages will require the services of a specialised brain surgeon. A dog with this condition will probably be enduring a great deal of pain. As a result, most pets suffering from the disease are euthanised.