What is Oral Cutaneous Fistula?
An oral cutaneous fistula (OCF) is a rare condition where an infection creates a path between the mouth and the skin. In non-medical terms, think of this as an unexpected tunnel from your mouth to your skin caused by an infection. “Fistulas” and “sinus tracts” are the technical terms you might come across, and they usually mean the same thing.
Common reasons for these oral-skin connections include lasting dental infections, injury, complications from dental implants, salivary gland issues, and tumors. People with this condition usually consult skin doctors (dermatologists) or surgeons, rather than dentists.
Recognizing a fistula isn’t simple. Its symptoms are few and often not distinctive, so it needs a careful examination to identify the condition. Gradual infections caused by dental problems, called odontogenic fistulas, have a good outlook if treated quickly. In contrast, fistulas associated with cancer can lead to serious problems and can even be life-threatening.
What Causes Oral Cutaneous Fistula?
Odontogenic cutaneous fistulas, which are connections between the mouth and skin, are mostly caused by bacteria invading the dental pulp, the central part of the tooth. This can happen due to tooth decay, injury, or other causes. If the affected tooth isn’t treated, the pulp dies and the infection spreads around the area. While most of these fistulas open in the mouth, chronic dental infections can progress and create an abscess in the jawbone. If this inflammation breaks down the bone and surrounding tissue, the infection can spread to nearby muscles in the jaw and upper jaw.
Appearances of facial skin fistulas and sinuses due to bone inflammation, or osteomyelitis, are not common. They are more likely in patients with uncontrolled diabetes, patients who have received radiation treatment to the jaw, are suffering from bone disorders such as Paget’s disease or osteopetrosis.
Other factors causing oral skin fistulas include certain medications that can lead to bone death in the jaw. These include bisphosphonates and anti-resorptive medicines, as well as intravenous therapies that hinder blood vessel growth. Patients typically use these medications to treat diseases that affect the bones, like bone metastases (spread of cancer), malignant hypercalcemia (high calcium levels in blood), multiple myeloma (cancer of plasma cells), and osteoporosis (bone loss).
Injury or surgical repair can also lead to traumatic fistulas. One research study found that patients who had undergone chemotherapy and radiotherapy had a higher risk of developing a fistula.
Complications can also occur from dental implants due to a mix of infections, reactions from the body, or lack of reactions. In one case, a patient developed an oral skin fistula connected to a dental implant after three months.
Fistulas can even mimic a harmless cyst caused by an ectopic salivary gland, a gland that’s not located where it should be. In one interesting case, a 24-year-old man had irregular clear drainage on both sides of the middle of his neck. The doctors removed the lesion surgically and found out that it was tissue from a misplaced salivary gland.
Periapical actinomycosis, a specific type of bacterial infection in the jaw area, is very uncommon but can result in an oral skin fistula.
In very rare cases, fistulas are a result of a tumor. The most common oral cavity tumor is the squamous cell carcinoma. If a fistula forms due to this, it usually indicates a poor prognosis as by the time of diagnosis, the disease has most likely spread through the lymphatic system.
Risk Factors and Frequency for Oral Cutaneous Fistula
A comprehensive study that analyzed 75 cases of skin infections related to dental problems (odontogenic cutaneous fistulas) over an eleven-year period found that the average patient’s age was 45. The most affected group were people aged 51 and over. There were a slightly greater number of women affected as compared to men, with a ratio of 1.14 to 1. Factors that were suspected to cause these dental infections and the formation of sinus tracts (channels from the source of infection to the skin) include inadequate dental hygiene, dry mouth (xerostomia), and unsatisfactory surgical procedures. In the majority of cases (87%), these infection channels originated from mandibular teeth (teeth in the lower jaw).
- The average age of the patients was 45.
- People aged 51 and over were the most affected (28%).
- The ratio of women to men affected was 1.14 to 1.
- Poor oral hygiene, dry mouth, and poor surgical procedures were suspected causes of these dental infections.
- In 87% of cases, these infection channels came from teeth in the lower jaw.
Furthermore, in a study by Lee et al., out of 33 patients, two had fistulas connected to a specific type of bacteria (actinomycosis), while one patient’s fistula was believed to have resulted from bone damage (osteoradionecrosis) following radiation treatment for cancer in the lower jaw (mandible cancer).
Signs and Symptoms of Oral Cutaneous Fistula
Most commonly, dental infections can cause skin openings or “fistulas” on the face. While acute infections cause severe pain, chronic dental infections might not have any symptoms, complicating their diagnosis. These infections often fail to get identified correctly, especially when they don’t cause pain. Individuals with such conditions typically recount periods where their skin problems seem to get better on their own, and they often visit numerous doctors without getting a clear diagnosis. In fact, a study showed that over 80% of cases with these dental-related skin fistulas were initially misdiagnosed, resulting in recurring conditions.
Face fistulas related to dental problems usually appear near the jaw’s angle, the chin, and the cheeks. In nearly all cases, these fistulas are found next to the tooth causing the problem. However, less common locations have been reported and must be considered when examining a facial skin lesion. These include the inner corner of the eye due to an infection in an upper molar tooth, the side of the nose due to an infection in an upper canine tooth, and the neck due to an infection in a lower molar tooth.
Usually, dental-related skin fistulas look like a small lump on the skin. Others have described the typical skin fistula related to dental problems as a red, smooth, symmetrical lump, up to 2 centimeters in diameter, which may or may not drain fluid, and might cause the skin to retract as it heals. However, this condition can appear in several ways, including:
- “Dimpling” or small indents
- Abscesses
- Small, filled nodules on the skin
- Skin tracts or narrow, elongated spaces
- Cysts
- Scars
- Ulcers
Given the variety of skin manifestations, it’s critical to examine oral tissues when a skin lesion appears on the face and neck.
Rarely, the cause of facial fistulas is not related to dental problems. For instance, in long-term bone infections with drainage, pain might not be a symptom. Signs of a sinus tract inside the mouth might be a raised or a red-to-yellow ulcer that bleeds easily and releases pus. In certain actinomycosis cases, yellow granules can be observed upon examination. Infections of the saliva-producing glands show signs like swelling, pain, and difficulty in opening the mouth fully if the condition affects the parotid gland, the major salivary gland.
Testing for Oral Cutaneous Fistula
If you’re suspected to have an odontogenic cutaneous fistula, which is a type of skin infection that originates from a tooth, your doctor may use several techniques to identify the problematic tooth. These can include pulp sensitivity tests, percussion (tapping on the tooth), and palpation (feeling the affected area).
Imaging tests are crucial for diagnosing this condition. Your doctor might perform a periapical x-ray (which focuses on a specific tooth), a panoramic radiograph (an x-ray that shows all the teeth, jaws, and sinuses), or a cone beam CT scan (a special type of x-ray that provides more detailed images).
These images can show bone loss around the tooth in question, pointing to the problematic tooth. To further visualize the path and source of the skin infection, your doctor might place a gutta-percha point (a small, rubber-like material) into the opening of the fistula prior to taking the x-ray.
Treatment Options for Oral Cutaneous Fistula
The complete healing of the fistula (which is an abnormal connection between two parts of the body) is achieved through proper dental treatment. This can be done via root canal treatment or tooth extraction if the affected tooth is causing the issue. Generally, fistulas self-heal within two weeks without needing further assistance.
However, it’s not uncommon for a small mark or darker patch of skin to remain where the fistula was. These residual signs usually get better over time, but they can persist for several months. If the remaining scar is bothersome for cosmetic reasons, surgical treatment can be considered to improve its appearance.
In one study conducted by Andrews and his colleagues, they found a helpful method to close a type of fistula known as an oral cutaneous fistula, which connects the mouth and the skin. They used a technique called negative-pressure vacuum-assisted closure (VAC). This procedure uses a medical device that helps promote wound healing by applying negative pressure (a vacuum) to the wound.
What else can Oral Cutaneous Fistula be?
Orocutaneous fistulas (OCF) are rare and are often wrongly diagnosed. This is because they can originate from dental issues, but are often mistaken for other conditions. In a study by Lee and colleagues, most patients were initially misdiagnosed. These oral skin passages were misread as:
- Epidermal cyst (24.2% of cases)
- Furuncle, which is a boil (21.2% of cases)
- Subcutaneous mycosis, a type of fungal infection under the skin (15.2% of cases)
- Squamous cell carcinoma, a type of skin cancer (9.1% of cases)
- Basal cell carcinoma, another type of skin cancer (6.1% of cases)
- Foreign body granuloma, which is an inflammation caused by a foreign substance (6.1% of cases)
Other conditions that should be considered for differential diagnosis can include:
- Tuberculosis infection
- Pyogenic granuloma, a vascular lesion
- Suppurative lymphadenitis, a condition characterized by swollen lymph nodes
- Salivary gland fistula, an abnormal passage within the salivary gland
- Carcinoma, a type of cancer
What to expect with Oral Cutaneous Fistula
Odontogenic cutaneous fistulas, which are abnormal connections between the inside of the mouth and the skin, usually get better once the problem tooth is treated. Often, they heal on their own without requiring additional procedures. However, they may leave a scar that requires surgical treatment to improve its appearance.
Possible Complications When Diagnosed with Oral Cutaneous Fistula
About half of the people who have dental-related skin sores on their face and neck are misdiagnosed at first. This could lead to unnecessary procedures like biopsies, skin surgeries and long-term use of antibiotics. In some cases, they might even receive radiotherapy before the dental cause is found. If not diagnosed and treated promptly, these sores can leave unwelcome scars.
Common Mistakes in Diagnosis:
- Biopsies
- Skin surgeries
- Chronic antibiotic therapy
- Unwanted radiotherapy
- Not finding the dental cause in time
Potential Consequences:
- Delayed diagnosis
- Unpleasant scars
Preventing Oral Cutaneous Fistula
Having good oral hygiene is the best way to prevent a condition known as oral cutaneous fistula (OCF), which is an abnormal connection between the mouth and the skin. This can be done by protecting against cavities – which can lead to an infected tooth or gums – through regular tooth brushing, flossing, and drinking fluoridated water, which is often found in community water supplies. It’s also important to get regular dental check-ups. If you ever experience a toothache or find an abscess (a pocket of pus) in your mouth, you should immediately see a dentist.
