What is Viral Infections of the Oral Mucosa?
The mouth can often show signs of viral illnesses. These illnesses might not always visibly show symptoms, but when there’s damage to mouth cells because of a virus, or if the immune system is responding to the virus, oral lesions – or sores – can appear.
Oral sores caused by viruses are a common sight for a number of healthcare providers like your family doctor, dentist, ear-nose-throat specialists, and skin specialists. However, it can be tricky to figure out exactly what’s causing the sores because the ways they appear and the types of germs causing them can vary a lot.
Viruses containing DNA, like the ones from the Herpes, Papilloma, and Pox virus families, are known to cause mouth sores. Similarly, RNA viruses, including enteroviruses and paramyxoviruses, can affect the mouth too.
Knowing exactly what is causing the sores can sometimes be tricky. Getting to know about these sores in due time reduces the risk of further complications. This prompt recognition is very important, especially in people living with HIV or AIDS, as these sores often increase as the disease advances.
What Causes Viral Infections of the Oral Mucosa?
Viruses from the Herpesviridae family are the most common source of mouth infections. These infections are capable of lying low and resurfacing later to cause a secondary infection. There are eight types of this virus that can cause human diseases: herpes simplex (HSV-1 and HSV-2), varicella-zoster (VZV or HHV-3), cytomegalovirus (CMV or HHV-5), human herpes viruses (HHV-6, HHV-7 or HHV-8), and the Epstein-Barr virus (HHV-4).
Primary Herpetic Gingivostomatitis (PHGS) is the first type of infection with herpes viruses (both HSV-1 and HSV-2), causing painful sores on the skin and mucous membranes. These types of viruses can be transmitted through bodily fluids or direct contact.
Cold sores (Herpes Labialis) appear in approximately 40% of infected individuals following the first infection with the herpes virus. It happens due to virus reactivation caused by stress, weak immune system, and exposure to sunlight.
Chickenpox is a well-known disease normally seen in children that’s also caused by a member of the Herpesviridae virus family. It can be spread through breathing the same air as an infected person or touching the spots.
Shingles is a disease that also comes from the varicella-zoster virus, presenting in people with weakened immune systems as painful, blistering skin rashes.
Mononucleosis, often called “mono” or the “kissing disease”, is caused by the Epstein-Barr virus, which infects specific white blood cells in the body. Most often seen in adolescents, it can be mainly spread through saliva.
Oral Hairy Leukoplakia refers to white, hairy patches in the mouth and is caused by Epstein-Barr virus, often marking the first sign of an HIV infection.
The Cytomegalovirus (HHV-5) is another member of the Herpesviridae family. It can lead to birth defects if a baby is infected during pregnancy but usually doesn’t cause any symptoms in a person with a healthy immune system.
Kaposi Sarcoma, a cancer type linked to human herpesvirus 8 (HHV-8) mostly seen in those with weak immune systems, is the main cause of cancer in untreated HIV patients.
The human papillomavirus (HPV) causes oral growths that can either be noncancerous, precancerous, or cancerous. It spreads primarily through direct contact. Common warts (Verruca Vulgaris) are often caused by HPV subtypes 2 and 57. Oral squamous papillomas are common growths in the mouth caused by HPV subtypes 6 and 11.
Meanwhile, conditions like genital warts and Heck Disease are caused by specific HPV subtypes. Molluscum contagiosum, a skin disease, is caused by the Poxvirus and is commonly found in individuals with weakened immune systems.
RNA viruses, including Enteroviruses like Coxsackievirus A and B, frequently cause throat infections, typically affecting children during summer. Herpangina and Hand, Foot, and Mouth Disease are caused by specific serotypes of the Coxsackievirus.
Acute lymphonodular pharyngitis, a throat infection featuring fever and mouth sores, is caused by a specific type of the Coxsackie virus. Measles, caused by a contagious virus that spreads through the air, has significantly decreased thanks to widespread vaccination.
Risk Factors and Frequency for Viral Infections of the Oral Mucosa
Herpes simplex viruses affect 60 to 90% of the global population. The infection typically spreads in childhood and is slightly more common in low-income social groups. Non-genital herpes, often caused by HSV-1, has decreased since the 1980s. Approximately 5 to 10% of people are estimated to shed the virus in their oral secretions.
Chickenpox cases and related complications have greatly reduced due to widespread vaccination. However, complications from the infection affected roughly 4.2 million people worldwide in 2014, leading to about 4,200 deaths per year. The disease predominantly affects children.
Shingles can affect anyone, but approximately 30% of the general population will get it at some point in their lifetime, possibly increasing for those aged 85 and above. Those over 50, people with weakened immune systems, and individuals under stress are more at risk.
The Epstein-Barr virus, which usually leads to latent infection and sometimes infectious mononucleosis, has infected over 90% of the world’s population. Mostly acquired in childhood, the virus typically arises during adolescence, and is the cause of about 90% of mononucleosis cases.
- Oral hairy leukoplakia, result of EBV, is mainly observed in individuals with immune deficiencies like HIV.
- About 50% of the US population is estimated to have positive serology for Cytomegalovirus (CMV). The disease is often acquired in childhood and may also be vertically transmitted. The prevalence increases with age, reaching almost 100% in developing countries.
- There are four types of Kaposi Sarcoma, each with different prevalence among different groups of people. It is often seen in males with Mediterranean or Eastern European descent and can be more aggressive in African patients, specifically those from sub-Saharan Africa. This version can occur frequently among HIV-negative individuals from this region.
- Those with chronic immune suppression like solid-organ transplant recipients can also develop Kaposi Sarcoma, as can HIV-infected men. However, due to the introduction of antiretroviral therapy, the occurrence of the disease in HIV-patients has reduced.
Human Papilloma Virus (HPV) has an estimated global prevalence of about 10%. It is the most common sexually transmitted disease, with women in their twenties at the highest risk. Thankfully, the prevalence declines as individuals age. The majority of oral cavity HPV infections result in benign growths. There are also certain syndromes like Down syndrome and Cowden syndrome, which have been linked to multiple oral papillomas. Similarly, Focal epithelial hyperplasia also has a genetic link and often manifests in Native American populations.
Molluscum contagiosum, yet another viral infection, is prevalent among pediatric patients, especially those aged 1 to 4 years old in the United States. Adults can also contract the infection, usually in the genital region, implying sexual transmission. It is particularly common among people with a compromised immune system, with about 20% of HIV patients contracting the infection.
Enteroviruses, another class of viruses, can lead to conditions like Hand, Foot, and Mouth Disease (HFMD), herpangina, and acute lymphonodular pharyngitis. The severity and complications of the infection can vary based on the patient’s age, and are mostly seen in children. Although enterovirus infections usually occur in summer and fall, sporadic occurrences happen year-round, especially in tropical regions.
The prevalence of measles has significantly reduced due to routine childhood vaccinations with the MMR (measles, mumps, and rubella) shot. This led to the disease’s eradication in the year 2000. However, opposing views on vaccination have led to a resurgence of the disease, with hundreds of cases reported in 2019, primarily among unvaccinated individuals.
Signs and Symptoms of Viral Infections of the Oral Mucosa
DNA and RNA viruses can cause many illnesses that come with differing symptoms. These viruses typically lead to symptoms occurring in different body areas, including the mouth. Let’s explore each virus and its symptom manifestations.
DNA Viruses
Herpesviridae Family
When someone first gets infected with the herpes simplex virus, either type 1 or 2, they may develop a condition called Primary Herpetic Gingivostomatitis. This condition generally shows up as painful redness and inflammation in the mouth and gums, along with tiny, sore ulcers.
Herpes labialis, commonly known as cold sores, is a recurrent infection involving the herpes simplex virus. These sores typically occur around the lips and sometimes inside the mouth. Patients often experience a burning sensation before the sores begin to form.
Chickenpox is an illness caused by the varicella-zoster virus. It typically leads to a skin rash and blisters which appear to have a ‘dew drop on a rose petal’ look. In some instances, painless blisters may appear in the mouth before the skin rash.
Shingles is also caused by the varicella-zoster virus. Early signs include pain or tingling in a certain area followed by a linear spread of blistering lesions. If the virus affects specific facial nerves, oral pain and blisters in the mouth and ear may occur. This is referred to as Ramsay Hunt Syndrome.
Infectious Mononucleosis may cause symptoms of fever and a sore throat, alongside various oral lesions, in some people who are affected.
Oral Hairy Leukoplakia, which occurs due to the Epstein-Barr virus, appears as a white, rough patch normally found on the side of the tongue.
Most individuals infected with the cytomegalovirus don’t show any signs. However, some may develop ailments such as enlarged liver and spleen, low platelet count, and jaundice. In some cases, non-specific mouth ulcers may arise.
Kaposi Sarcoma, caused by the HHV-8 virus, presents as red, blue, or purple lesions, or patches on the gums, hard palate, or top surface of the tongue. These may sometimes ulcerate and bleed.
HPV, or human papillomavirus, can cause a variety of oral conditions including common warts (Verruca Vulcanis), Oral Squamous Papilloma, sexually transmitted oral lesions (Condyloma Acuminatum), and painless raised patches or plaques (Heck’s disease).
Molluscum Contagiosum often affects those with compromised immune systems. Associated oral lesions appear as small lumps with a dimple in the middle.
RNA Viruses
Enteroviruses
Herpeangina is usually manifested as vesicles or small ulcers in the back part of the throat and pain.
Hand, foot, and mouth disease often cause a rash and flu-like symptoms, including a low-grade fever and generalized feeling of being unwell. Vesicles or small blisters may appear inside the mouth which can subsequently turn into ulcers.
Acute Lymphonodular Pharyngitis is usually associated with a sore throat and small yellow or pink nodules in the back part of the throat.
Paramyxoviruses
Measles, or Rubeola, is an illness characterized by three stages. The first stage typically includes symptoms such as a cough, redness of the eyes and small red spots with blue or white centers appearing in the mouth. These spots are known as Koplik spots. The second stage is characterized by a skin rash, which spreads out from the center of the body. The final stage represents the resolution of the disease.
Testing for Viral Infections of the Oral Mucosa
Let’s talk about a few different types of DNA and RNA viruses and how doctors diagnose them:
Herpes Viruses:
The first type of herpes, Primary Herpetic Gingivostomatitis, can usually be identified by the visible sores in the mouth. If they don’t heal within ten days, other health conditions may be considered. In rare cases, this can come back in people with strong immune systems, and a more serious conditions like leukemia may be investigated. Sometimes, testing like Polymerase Chain Reaction (PCR) or a Tzanck test is needed. A Tzanck test looks for changes in the cells that might mean a virus is present.
The second type, Herpes Labialis, also known as cold sores, is typically diagnosed by where the sores are located. If it’s not clear, doctors may use various tests such as a viral culture, PCR or Histologic examination which is the examination of cells under a microscope.
Chicken Pox and Shingles:
Chicken pox is usually diagnosed by looking at the obvious symptoms and examining the patient physically. Shingles, a reactivation of the chickenpox virus, is diagnosed the same way. The distribution of the shingles rash is generally limited to one side of the body which aids in its diagnosis.
Other Viruses:
Infectious Mononucleosis, or “Mono,” is diagnosed by testing for specific antibodies in the blood related to the Epstein Barr Virus (EBV). Cytomegalovirus is more common in patients with HIV/AIDS and can be diagnosed by PCR or blood tests. Oral Hairy Leukoplakia, Kaposi Sarcoma, and Human Papilloma Virus, are often identified by a biopsy which is a procedure that involves taking a small sample of tissue for examination under a microscope.
Poxviridae and RNA Viruses:
Molluscum Contagiosum, a skin disease caused by the Molluscum Contagiosum Virus (MCV), is diagnosed by a skin biopsy. Several diseases caused by RNA viruses like Herpangina, Hand, Foot, and Mouth Disease, are diagnosed based on physical examination and sometimes the virus may be cultured from samples of intact blisters for further testing. Measles or Rubeola is usually diagnosed based on visible signs and symptoms, such as the characteristic Measles rash, but sometimes a blood test may be done for confirmation.
Treatment Options for Viral Infections of the Oral Mucosa
Herpesviridae:
Primary herpetic gingivostomatitis (PHGS) typically resolves itself in a little under two weeks. Treatment for this condition aims to soothe symptoms. Patients should rest, eat soft foods, and drink plenty of fluids. Oral discomfort can be managed with pain relievers. Chlorhexidine mouthwash is used to prevent the sores from becoming infected. If patients have a weakened immune system or are severely ill, antiviral medication can be prescribed.
Herpes labialis, or cold sores, usually heal within two weeks without leaving scars. Applying antiviral cream early in the outbreak can help to shorten its duration. In patients with weakened immune systems, an antiviral medication known as acyclovir is usually the preferred treatment.
Chickenpox is managed through supportive measures such as over-the-counter pain relief, increased fluid consumption, and maintaining a healthy lifestyle. Once the characteristic rash has formed crusts, usually within five to ten days of appearing, the person is no longer contagious.
Shingles is managed with similar supportive care, with the sores typically healing in around three weeks. Those with severely weakened immune systems might need to be treated with oral acyclovir.
In most cases, infectious mononucleosis resolves by itself and treatment is customized to the specific symptoms of the patient. Antibiotics such as amoxicillin or ampicillin should be avoided due to the risk of causing a skin rash.
Oral hairy leukoplakia, a type of oral lesion, is treated with topical agents such as vitamin A and podophyllum. In HIV patients, antiretroviral therapy, which helps improve immune function, is crucial.
Cytomegalovirus is typically treated with medication like ganciclovir. As with oral hairy leukoplakia, antiretroviral therapy is important in improving the immune function.
The treatment for Kaposi Sarcoma, a type of skin cancer, largely depends on the individual characteristics of the lesions, with potential methods ranging from surgery, laser treatment, and sclerosing agents, to localized chemotherapy and radiation.
Human papillomavirus causes various types of oral lesions, such as verruca vulgaris, oral papilloma, and condylomas, which generally require surgical removal. If the lesions are not completely removed, they are likely to recur. Similarly, lesions resulting from a condition known as Heck’s disease may recur particularly in patients with weakened immune systems. Topical treatments are typically recommended.
Molluscum contagiosum, a viral skin infection, is usually treated by removing the lesions with surgery, cold therapy, or a chemical blistering solution.
Most coxsackie virus A infections, which cause herpangina, hand-foot-mouth- disease, and acute lymphonodular pharyngitis, are self-limiting and resolve naturally within seven to ten days.
Measles, also known as rubeola, has become less common due to widespread vaccination. However, if an infection does occur, the management is mainly supportive. In high-risk groups such as pregnant women, young children, and individuals with a weakened immunity, treatment with immune serum globulin might be necessary. It is most effective if given within six days of exposure to the virus.
What else can Viral Infections of the Oral Mucosa be?
Here are some conditions that may be present with similar symptoms:
- Squamous cell carcinoma
- Candidiasis (yeast infection)
- Primary or secondary syphilis
- Gonorrhea
- Tuberculosis
- Bacterial pharyngitis (sore throat)
- Pemphigus vulgaris (a rare skin condition)
- Geographic tongue (a condition that causes a map-like pattern on the tongue)
What to expect with Viral Infections of the Oral Mucosa
Most viral infections in the mouth usually get better on their own and are managed with supportive care that helps relieve symptoms. Nevertheless, severe cases that are left untreated could result in significant health complications. Therefore, it is crucial to identify specific viruses that can pose a high risk to patients’ health progress. For example, HPV (Human Papillomavirus) and herpes viruses can work together to cause oral cancer.
Particularly, EBV (Epstein-Barr Virus), HHV-8 (Human Herpesvirus 8), and CMV (Cytomegalovirus) are linked with the development of malignant tumors, including lymphomas (a kind of blood cancer), nasopharyngeal or gastric carcinomas (cancer that starts in the nose or stomach), Kaposi’s sarcoma (a rare kind of skin cancer), and Castleman’s disease (a rare condition that affects the lymph nodes).
Possible Complications When Diagnosed with Viral Infections of the Oral Mucosa
Herpesviridae viruses, like Primary Herpetic Gingivostomatitis (PHGS) and herpes labialis, often reoccur, especially in people with weak immune systems. If left untreated, the infection can spread. Sometimes, reactivation of HSV-1, especially in the geniculate ganglion, may lead to Bell palsy, which causes facial nerve damage. However, the exact reason for this is not clear.
Severe chickenpox can cause serious complications, such as Reye’s syndrome, encephalitis, and Guillan Barre. After recovering from a shingles infection, some patients can experience severe lingering pain due to nerve scarring. Some affected areas may also develop hyperpigmentation and scarring.
The Epstein-Barr virus (EBV) causes infectious mononucleosis and can lead to more severe health issues, such as hepatitis, aplastic anemia, or splenic rupture. This virus has also been linked to African-endemic Burkitt’s lymphoma, non-Hodgkins lymphoma, and nasopharyngeal in patients with weakened immune systems.
Although oral hairy leukoplakia is often benign, patients may experience minor complications like oral pain. Cytomegalovirus can complicate things in at-risk groups, such as pregnant women, who may transmit the virus to their unborn baby. In patients with weak immune systems, this virus can lead to retinitis and blindness.
Kaposi sarcoma patients can experience complications like ulceration and bleeding. Human papillomavirus (HPV) can cause discomfort, cosmetic issues, and accidental bite injuries. However, a high-risk subtype, HPV-16, poses a risk of oral cancer, mainly when found in smokers. The full implications of HPV infection are not yet fully understood.
Molluscum Contagiosum patients may experience minor complications such as redness and swelling of the lesions. Patients with weak immune systems may develop more severe lesions and extensive oral involvement. Some patients may also develop eczematous plaques around the lesions.
Infections from coxsackie virus, such as Herpangina, Hand, Foot, and Mouth Disease, and Acute Lymphonodular Pharyngitis, can cause oral lesions and pain, potentially leading to dehydration. In severe cases, it can cause neurological issues like encephalitis or aseptic meningitis.
While complications from primary measles infection are rare nowadays due to the measles vaccine, it used to cause serious health problems including pneumonia, keratoconjunctivitis leading to blindness, and brain infections. These cases were commonly found in patients with weakened immune systems or vitamin A deficiency.
Preventing Viral Infections of the Oral Mucosa
As explained in this article, most viral infections in the mouth are harmless and usually heal on their own. However, some may get worse over time and lead to potentially dangerous complications. Additionally, developing certain types of mouth sores caused by viruses might indicate an undiagnosed problem with the immune system and can increase the chances of developing cancer.
Because of this, it’s not a good idea to ignore sores in the mouth that seemingly appear harmless or mild symptoms. This will ensure that treatment can start when needed, the right specialist can be consulted, and measures can be taken to prevent the disease from getting worse if necessary.
