Dermoid Sinus in Dogs

Dermoid sinus is an inherited trait found in certain breeds of dogs. It consists of a cyst beneath the skin, usually along the spine. Dermoid sinus typically forms while the puppy is still in its mother's womb. Learn more about this inherited condition.

Causes and Risk Factors for Dermoid Sinus in Dogs

Dermoid sinus is a genetic disorder that is passed from down from a puppy's parents. Because it is carried by a recessive gene, both parents must have the gene in order to pass the condition to their puppies. Dermoid sinus may not affect all puppies in the litter; some of the puppies may be carriers, showing no signs of the disease. 

Rhodesian ridgebacks, and mixed breed dogs who have Rhodesian ridgeback heritage, are most likely to develop this condition. Dermoid sinus also sometimes appears in Shih Tzus and boxers. Most dogs with this condition develop symptoms when they are still quite young. 

Symptoms of Dermoid Sinus in Dogs

If your dog has dermoid sinus, he will have a cyst beneath his skin, most likely on his back, near his spine. There may be holes in the skin of your dog's back, and hair may poke out of them. Your dog may have weeping tracts or lesions on his back, and there may be swelling in some areas. 

Dermoid sinus leaves your dog vulnerable to inflammation of the spinal cord and the covering surrounding the brain, a condition known as meningitis. He may also develop myelitis, or inflammation of the spinal cord. Symptoms of myelitis and meningitis include stiffness and rigidity, pain, and fever.

Diagnosing and Treating Dermoid Sinus in Dogs

Your vet will need a complete physical exam and medical history in order to diagnose dermoid sinus. Blood tests and urinalysis can check for signs of infection. X-rays can help your vet determine how deep the dermoid sinus cavities in your dog's skin are. MRIs or CAT scans may be necessary if your dog is showing symptoms of nervous system damage or infection.

Dermoid sinus may not require treatment if the lesions are not weeping, and not deep enough to connect to the spinal canal. If your dog's lesions are deep enough to connect to the spinal canal, or are draining, your vet can perform surgery to remove the abnormal tissue. If the condition has already affected your dog's nervous system, than he may never return to normal, even with treatment.

If your dog has an infection, especially myelitis or meningitis, then he may need antibiotic therapy. If your dog develops an infection of the spinal cord, spinal cord covering or brain covering, then his prognosis will be significantly worsened. It's for this reason that it's important to seek treatment for dermoid sinus right away. 

If your dog has dermoid sinus, he should be neutered. Dogs with this hereditary condition should never be bred, since they can pass the defective gene, and possibly the condition, onto their puppies.