Hereditary Problems of the Chihuahua and Dachshund

Energetic and portable, small dogs can be great companions. The Chihuahua and the dachshund are among the shortest dogs; the Chihuahua and the miniature dachshund stand around 5 or 6 inches at the shoulder, compared to the standard dachshund's 8 or 9 inches. Though small in stature, both have big personalities, as well as potential inherited health problems.

Tiny and tenacious, the mighty Chihuahua embodies the phrase "dynamite comes in small packages." Despite his plucky personality, he has a variety of potential hereditary problems. It's easy for his kneecap to pop out of place, known as a luxating patella, a condition that may require surgical correction. In mild cases, the kneecap will slip back into place on its own. Limping or hopping when running are signals a Chihuahua needs to have his knees checked. It's not unusual to see a Chihuahua with an open fontanel -- the soft area under his forehead's skin -- referred to as molera. When the bony plates in his skull don't fully fuse and harden, the dog may develop hydrocephalus, the accumulation of fluid around the brain. Though molera can have serious consequences, including seizures and death, a Chihuahua with the condition can lead a healthy, happy life, though he needs to be careful he's not injured if he interacts with other dogs and children who may play too vigorously with him.

The Chihuahua's eyes are distinctive, protruding and alert, and vulnerable to a variety of conditions. Glaucoma, corneal dystrophy, lens luxation, iris atrophy and keratitis sicca -- known as dry eye -- are things to keep your eyes open for. As well, those prominent eyes can be injured more easily than a dog with eyes that are a bit more recessed. If born with a portosystemic shunt, a Chihuahua's blood isn't making it to his liver, causing an accumulation of toxins in his body and stunted growth. Surgery is a must for this condition. His tiny mouth often needs more attention than a larger dog, because it may not have room for all his teeth.

The standard and miniature dachshund share many of the same hereditary health problems. When you look at his long frame, it's not hard to guess that the most common problem for this tubular pup is with his back. His morning leap off the bed can easily injure a disk, affecting his ability to walk and his ability to eliminate waste. In addition to a long torso, he has a deep chest, making him prone to bloat. Bloat, when the stomach fills with air, can lead to gastric torsion, a dangerous condition when the stomach twists and cuts off the blood supply.

The dachshund has the dubious honor of being one of the few breeds affected by a skin condition called acanthosis nigricans, which is a blackening of the skin. The dog's armpits and groin will develop think, dark skin. Though there's no known cure, it is improved with vitamin E supplements. He's prone to other diseases including hypothyroidism, epilepsy, glaucoma, progressive retinal atrophy and von Willebrand's disease. It's especially important to monitor the dachshund's weight to help maintain his intervertebral health. Excess weight will put more stress on his back. Activities that stress his back and spine should be avoided, as spinal injury can lead to permanent paralysis. Access ramps to chairs, sofas and bed will minimize his risk of injury.

If you're trying to choose between a dachshund and Chihuahua, there's no guarantee one breed will be healthier than another. A healthy Chihuahua has a long life span -- between 12 and 20 years. It's important to note that the popular extra-small Chihuahuas, bred to be especially tiny -- around 2 or 3 pounds -- are prone to more medical problems, and often have a much shorter life expectancy. A healthy dachshund can expect to live around 12 to 15 years. If you're going through a breeder, search the Canine Health Information Center database to find a puppy's parents, as well as the Orthopedic Foundation for Animals database. If you can't find your potential pup's parents through their websites, the dogs haven't been tested and cleared for basic health tests to include evaluation for many congenital illnesses.