Dermoid Sinus
Learn what the condition is, how it may be detected early, how it is treated or managed, and which breeds or species are linked to it.
Condition snapshot
A concise guide to the condition’s pattern, detection, management and urgency.
Breeding advice appliesUse the condition’s screening guidance and veterinary or genetics advice before breeding an affected or at-risk animal.
This snapshot is a general guide, not a diagnosis or treatment plan. New, severe or worsening signs require veterinary assessment.
About the condition
Dermoid sinus is a congenital developmental defect in which the tissues that form the skin and the tissues associated with the spinal column fail to separate completely during embryonic development. This leaves a narrow tube or tract extending inward from the skin. The condition is best known in Rhodesian Ridgebacks, where it is closely associated with the genetic background that produces the dorsal ridge, although it has also been reported in other breeds.
The sinus may end within the tissue under the skin or extend more deeply toward the spinal structures. Externally, there can be a small opening, dimple or tuft of hair along the midline, often near the front or rear end of the ridge. In some puppies the tract can be felt as a cord-like structure when the skin is gently lifted. Because the sinus is lined by skin-like tissue, hair, keratin and debris can collect inside it.
The major risk is infection. Bacteria can travel down the tract and create a painful abscess. If the sinus communicates with tissues close to the spinal canal, infection can progress to meningitis or other serious neurological disease. A previously well dog may then develop fever, neck or back pain, weakness or neurological deficits.
The condition does not resolve naturally with growth. Its significance depends on the depth and anatomical relationship of the sinus, which is why accurate classification is important before treatment. Early recognition allows planned surgery before infection complicates the area and makes the procedure more difficult.
The depth of the tract is clinically important because a superficial sinus may cause recurrent local infection, while a deeper tract can extend toward spinal structures and create more serious neurological risk.
The skin can be gently lifted to feel for a thin cord or tract beneath it. Visible clues include a small opening, dimple, tuft of hair or recurrent discharge.
Screening & Early Detection
Screening is based on careful examination of puppies because there is no widely available test that identifies carrier status or guarantees that a clinically normal dog cannot pass on risk. In Rhodesian Ridgeback litters, each puppy should be palpated along the dorsal midline from the head to the tail, paying particular attention to the areas immediately in front of and behind the ridge.
Examination is ideally performed by someone experienced with the condition because a subtle sinus can be missed. A puppy considered clear at the first check may be re-examined before leaving the breeder, particularly if the first assessment was uncertain.
When a sinus is suspected, imaging may be recommended to define its depth and relationship to the spinal canal. Ultrasound can help with superficial tracts, while CT or MRI provides more detailed information for complex cases. Signs of swelling, pain, discharge, fever or neurological change require prompt assessment for infection.
Breeding records should document affected puppies. Because the trait is associated with inherited ridge development in Rhodesian Ridgebacks, an affected dog should not be regarded as suitable breeding stock simply because the sinus is later removed successfully.
Diagnosis is usually made by careful physical examination of a puppy. Imaging such as ultrasound, CT or MRI may be used to determine how deeply the tract extends before surgery.
Treatment & Management
Definitive treatment is surgical removal of the entire sinus tract. Surgery is ideally performed before infection occurs, when tissue planes are clearer and the puppy is otherwise well. The complexity of the procedure depends on how deeply the tract extends. A superficial sinus may be removed relatively easily, whereas one approaching or entering spinal tissues requires a more specialised operation and careful pre-operative imaging.
The surgeon follows the tract from the skin opening to its deepest endpoint and removes it completely. Leaving a segment behind can allow recurrent cyst formation, infection or discharge. If an abscess or infection is already present, antibiotics and pain relief may be needed, and the timing of surgery is planned according to the severity and anatomical involvement.
Post-operative management includes wound care, restricted activity and monitoring for swelling, discharge, pain or neurological abnormalities. Dogs with a sinus that extended close to the spinal canal may need closer neurological observation during recovery.
After surgery, the incision is monitored for infection, fluid accumulation and neurological change. Complete removal usually gives a good result, but dogs with tracts attached to deeper tissues may need more intensive postoperative care and longer follow-up because residual or recurrent infection is more difficult to manage.
Breeds or species affected
Boxer
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Chow chow
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Kerry blue terrier
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Rhodesian ridgeback
Open dog breed description, care requirements and conditions
Shih tzu
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Siberian husky
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Yorkshire terrier
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