Cairn Terriers are a hardy breed with a lifespan of 13 to 14 years, but they’re prone to several serious health conditions that can shorten that span. Cancer is the leading killer of dogs past middle age across all breeds, and Cairn Terriers are no exception. Beyond cancer, this breed faces a handful of genetic conditions that are unusually common in their line, including liver shunts, a blinding eye disease, and a fatal neurological disorder that strikes puppies.
Cancer
Roughly one in four dogs will be diagnosed with cancer during their lifetime, and it’s the number one cause of death in dogs beyond middle age. Cairn Terriers can develop the same cancers that affect other breeds: lymphoma (which accounts for up to 24% of all new canine cancers), mast cell tumors on the skin, and hemangiosarcoma, a fast-moving cancer of blood vessel cells that most often hits the spleen, liver, or heart. Because Cairn Terriers tend to live into their teens, they have a long window of exposure to age-related cancers.
Liver Shunts
Cairn Terriers have an inherited tendency toward congenital portosystemic shunts, an abnormal blood vessel that allows blood to bypass the liver. Normally, blood from the intestines flows through the liver to be filtered before returning to the rest of the body. A shunt reroutes that blood, so toxins that would normally be cleared by the liver build up in the bloodstream instead.
A large screening study of over 6,300 Cairn Terriers identified 58 dogs with the condition, and because it’s inherited, affected dogs can pass it to their offspring. Puppies with liver shunts may seem small for their age, act disoriented or lethargic after meals, or have seizures. A bile acid blood test can flag the problem as early as 12 to 16 weeks of age. Surgery to close the shunt is possible, and many dogs do well afterward, but not all cases are operable. Without treatment, the condition can be fatal.
Ocular Melanosis and Glaucoma
Ocular melanosis is a condition that affects Cairn Terriers more than any other breed. Pigmented cells gradually accumulate inside the eye, thickening the iris and forming dark spots on the white of the eye. On its own, this buildup isn’t immediately dangerous. The problem comes later: those pigmented cells eventually block the drainage pathway that keeps fluid pressure balanced inside the eye.
Once drainage is blocked, pressure rises, causing glaucoma. According to researchers at Michigan State University’s College of Veterinary Medicine, the glaucoma that develops in Cairn Terriers with ocular melanosis is difficult to treat and often leads to permanent blindness. The condition affects both eyes and can also be painful. It may not show up until a dog is older, which is why the Cairn Terrier Club of America recommends eye exams starting at age two, with periodic follow-ups throughout the dog’s life. While blindness alone isn’t a direct cause of death, the chronic pain from uncontrolled glaucoma is one of the more common reasons owners face difficult end-of-life decisions.
Globoid Cell Leukodystrophy
This is the most devastating genetic condition in the breed, and it strikes early. Globoid cell leukodystrophy (GCL), also known as Krabbe disease, destroys the protective coating around nerve fibers in the brain and spinal cord. Affected puppies begin showing symptoms between 6 and 20 weeks of age. The signs are neurological and progressive: tremors, weakness in the hind legs, loss of coordination, blindness, and eventually incontinence.
There is no treatment. Affected puppies rarely survive past their first year. In documented cases, one puppy was euthanized at four months, while a West Highland White Terrier (a closely related breed that carries the same mutation) was euthanized at 12 months when blindness, tremors, and severe hind leg weakness became unmanageable. A DNA test now exists that can identify carriers before breeding, and responsible breeders use it to avoid producing affected litters.
Craniomandibular Osteopathy
Craniomandibular osteopathy, or CMO, causes abnormal bone growth along the jaw and skull in young dogs. It typically appears between 3 and 12 months of age. The hallmark symptom is pain when opening the mouth: 95% of affected dogs in one study presented with difficulty eating or pain when their jaw was touched. Other signs include facial swelling, drooling, fever, loss of appetite, and swollen lymph nodes under the jaw.
The good news is that the abnormal bone growth usually stops on its own once the skeleton matures, around one year of age. The bad news is that severe cases can fuse the jaw joint, permanently limiting how far the dog can open its mouth. In rare cases, bone overgrowth on the skull can compress the brain or brainstem. CMO is not typically a direct cause of death, but severely affected dogs that can’t eat or that develop neurological complications may need to be euthanized. A DNA test is available for this condition as well.
Kidney Abnormalities
Cairn Terriers are also screened for missing or malformed kidneys. Some puppies are born with only one kidney (renal aplasia) or with a kidney that didn’t develop properly (renal dysplasia). A dog can live a normal life with one healthy kidney, but if neither kidney functions well, the result is progressive kidney failure. The Cairn Terrier Club of America recommends ultrasound screening for puppies at 12 to 15 weeks to catch these problems early, since kidney disease can be managed but not reversed once it advances.
What Responsible Screening Looks Like
The Cairn Terrier Club of America recommends a specific panel of tests before any dog is bred. DNA swab tests can identify carriers of both GCL and CMO. Bile acid blood tests screen for liver shunts. Dilated eye exams by a veterinary ophthalmologist check for ocular melanosis. Kidney ultrasounds and patella exams round out the list. If you’re buying a Cairn Terrier puppy, asking the breeder which of these tests have been completed on the parents is the single most useful thing you can do to reduce the risk of losing your dog to a preventable genetic condition.