Inflamed Mouth (Stomatitis) Causes, Symptoms, Treatment

The mouth, including the tongue, palate, inner cheek and lips, can become irritated and inflamed for various reasons. The mouth has to contend with exposure to various substances on a daily basis and this is not only food and beverages. It is also used for breathing and speech. It is therefore not uncommon for irritation to occur as well as a host of other causes of inflammation, including infections.

What is stomatitis?

Stomatitis is a medical term for inflammation of the oral cavity, its lining and structures. We commonly refer to it as the mouth. It may involve a few isolated areas or the entire mouth. The signs of inflammation – pain, swelling, redness, warmth – are present to varying degrees. Pain is almost always a feature of stomatitis and mouth pain is known as stomatodynia.

When the inflammation involves specific structures in the mouth it may be referred to accordingly but still broadly falls under stomatitis.

Most of the time mouth inflammation is not serious. It quickly resolves on its own without any complications. However, certain causes can lead to recurrent or persistent stomatitis. These chronic causes of mouth inflammation can sometimes be serious. Treatment may not always be directed at the mouth inflammation and symptoms. Palliative treatment may be helpful for the symptoms but attending to the underlying cause may be more effective in chronic cases.

Symptoms of Inflamed Mouth

Soreness and pain are some of the common symptoms of inflammation. It may be generalized throughout the mouth or isolated to specific parts of the mouth. Along with pain, other signs of inflammation are also present such as redness. In extensive inflammation, open sores known as mouth ulcers may form in the inner lining of the mouth, cheek or palate.

Other lesions are less common. This may include white patches, plaques of spots on the inner lining of the cheek, gum and/or tongue. This is often seen with lichen planus and oral candiasis (mouth thrush). Red spots and vesicles (water-fluid bumps/blisters) may be seen with certain herpes simplex infection (oral herpes) and erythema multiforme.

Causes of Stomatitis

There are a wide range of causes of stomatitis. In acute cases it is often due to trauma (injury) from everyday activities like brushing too vigorously or from consuming very hot food or beverages. Infections are another common cause. An inflamed mouth must be investigated by a doctor as some of the causes can be serious.


  • Bacterial infections usually follow injury of the oral mucosa. This is often related to poor dental care, as with acute necrotizing ulcerative gingivitis (ANUG) ore sexually transmitted diseases (STD’s) like syphilis and gonorrhea.
  • Viral stomatitis is more frequently seen in children and related to childhood infections like chickenpox. It adults it is often due to the herpes simplex virus type 1 (HSV-1) and is usually recurring (recurrent herpetic stomatitis). Other infections like Epstein-Barr virus (EBV), cytomegalovirus (CMV) and reactivation of varicella zoster (shingles) are also on the rise, especially in immunocompromised patients, like with HIV infection.
  • Fungal infections are rarely seen in patients who are not immunocompromised. Oral candidiasis (Candida spp) is the more common cause but other rare fungal species may be seen especially in HIV positive patients. In diabetics, mucormycosis may also cause fungal stomatitis (Mucorales mold).

Injury and Irritation

Non-infectious inflammation is often related to mechanical trauma. This may include:

  • Vigorous brushing and/or flossing.
  • Poorly fitting dental implants, bridges or dentures.
  • Mouth biting.
  • Excessively hot foods.
  • Sharp, rough objects inserted in the mouth.

Other factors may cause chemical irritation or even hypersensitivity reactions. This includes :

  • Acidic foods.
  • Vitamin chews (chewables, chewing).
  • Tobacco (chewing and smoking).
  • Areca (betel) nut and betel leaf chewing.
  • Excessive gum chewing.

Drugs and Therapies

Dryness of the mouth is a common side effect of many drugs. Sometimes this dryness can aggravate underlying mouth problems. Depending on the type of drug, the substance itself can irritate and inflamed the mouth. Chemotherapy and radiation therapy for the treatment of cancer are among the most common causes of mouth inflammation.


Stomatitis is primarily seen in deficiencies of :

  • Vitamin C (scurvy)
  • Vitamin B3/Niacin (pellagra)
  • Iron (iron-deficiency anemia)

Autoimmune and Allergies

A number of autoimmune and allergic causes may cause stomatitis. The most well known autoimmune cause is Sjogren’s syndrome where excessive dryness of the mouth increases the risk of injury and infection of the mouth lining. Other causes like Behcet’s syndrome, Kawasaki disease and Steven-Johnson’s syndrome are less frequently seen.

Other immune related causes includes :

  • Lichen planus
  • Pemphigus vulgaris
  • Hypersensitivity to dental care products like toothpaste, mouthwash.
  • Food intolerance as is seen with gluten intolerance (sprue).
  • Individual allergies may vary from person to person but stomatitis often follows exposure to these agents.


Primary malignant tumors within the mouth (oral cavity cancer) or metastatic spread from other sites, especially with lymphoma or leukemia, may result in stomatitis and large ulcers may develop over time. Stomatitis may be further aggravated during cancer treatment – chemotherapy and radiation therapy.

Blood Disorders

Stomatitis is a concomitant clinical feature in certain blood disorders like :

  • Thrombotic thrombocytopenic purpura
  • Platelet disorders
  • Leukemia
  • Neutropenia

Other Causes

  • Inflammatory bowel disease
  • Burning mouth syndrome
  • Xerostomia (dry mouth)

Treatment of Stomatitis

The choice of treatment for mouth inflammation depends on the underlying cause. Drug therapy is usually administered but sometimes surgery may be required. Some of the drugs that are used for the treatment of stomatitis includes:

  • Topical corticosteroids and sometimes oral corticosteroids may be prescribed depending on the cause.
  • Anesthetics like lidocaine may be applied topically for pain management particularly when there are mouth ulcers.
  • Antibiotics for bacterial infections or antifungal agents for fungal mouth infections. Antiviral drugs are rarely used for viral mouth infections.
  • Bio-adherents like sucralfate adhere to ulcers and seal the area until it heals. This is prescribed for deep ulcers that are not otherwise healing.
  • Immune-modulating agents may be prescribed for autoimmune diseases that led to the mouth inflammation and oral ulcers.

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