This breed requires expert veterinary attention in areas such as birthing and dental care. Dental care is a must for these small dogs, whose jaw size makes for weaker teeth. Although daily brushing provides the best preventative measure, feeding a dental diet or using dental chews for dogs is an effective approach pet owners can take to help prevent and control accumulation of plaque and tartar to avoid consequences of severe periodontal disease. The best physical characteristics of dog food to contribute to cleaning a dog's teeth would be food that is large and dense, that way there is more time spent chewing which leads to the surface of the teeth being cleaned.
Chihuahuas, and other toy breeds, can be affected by hydrocephalus. Chihuahua puppies with hydrocephalus have an abnormally large head, are lethargic and do not grow at the same pace as their siblings. A true case of hydrocephalus can be diagnosed by a veterinarian, though the prognosis is grim. Apple head Chihuahuas can have moleras, or a soft spot in their skulls, and they are the only breed of dog to be born with an incomplete skull. This is not a defect; it is a normal adaptation facilitating the passage through the birth canal and growth and development of the domed type of forehead. The molera is predominant in the apple heads and is present in nearly all Chihuahua puppies. The molera fills in with age, but great care needs to be taken during the first six months until the skull is fully formed. Some moleras do not close completely and require extra care to prevent injury.
Chihuahua puppies can be at risk for hypoglycemia, or low blood sugar. Signs of hypoglycemia include lethargy, sleepiness, uncoordinated walking, unfocused eyes and spasms of the neck muscles or head pulling back or to the side, fainting and seizures. Hypoglycemia can be avoided with adequate nutrition and frequent feedings, especially for Chihuahuas who are younger, smaller or leaner. Chihuahua owners should have a simple sugar supplement on hand to use in emergencies, such as Nutri-Cal or original formula Karo syrup. These supplements can be rubbed on the gums and roof of the mouth to rapidly raise the blood sugar level.
On the other hand, as with any dog, owners should take care not to overfeed their Chihuahua, since obesity can result in increased rates of joint injuries, tracheal collapse, chronic bronchitis, and shortened life span. As in other breeds with large protruding eyes, Chihuahuas are prone to eye infections or eye injury. The eyes may water in response to dry air, dust or air-borne allergens. Collapsed trachea is a health concern that is characteristic of the Chihuahua breed. Chihuahuas may tremble or shiver when stressed, excited or cold. Chihuahuas, especially the short coat variety, are less tolerant of cold than larger breeds, and require a sweater and/or boots in cold weather. They will seek warmth in sunshine, under blankets, or on furniture, or human laps.
Chihuahuas are also known for luxating patella, a genetic condition that can occur in all dogs. In some dogs, the ridges forming the patellar groove are not shaped correctly and a shallow groove is created, causing the patella to luxate or slip out of place, sideways. The knee cap sliding across the bony ridges of the femur can cause some pain. The affected chihuahua will hold its leg flexed, and foot off the ground until the quadriceps muscle relaxes and lengthens, after which the animal feels no discomfort and continues with activity.
Chihuahuas are also prone to some heart-related disorders, such as heart murmurs and pulmonic stenosis, a condition in which the blood outflow from the heart's right ventricle is obstructed at the pulmonic valve. Some Chihuahuas may present separation anxiety as a result of being so close and loyal to their owner. This is a fairly common cause behind any pacing, excessive salivating, destructive chewing, or barking, howling or whining in dogs. There are many treatments and tips to help prevent separation anxiety in dogs.