Stomatitis – Causes of Mouth Inflammation, Irritation

Stomatitis is a general term for inflammation of the oral cavity, its lining and structures. 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.

Generalized inflammation may present with pain, redness of the mouth lining and possibly some swelling. However, focal areas of severe inflammation may cause ulcers. Also commonly referred to as mouth sores or aphthous ulcers, it may present as one or more ulcers in the mouth.

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. Red spots and vesicles (water-fluid bumps/blisters) may be seen with certain herpes simplex infection and erythema multiforme.

Causes of Stomatitis


  • 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

Chemotherapy and radiation therapy for the treatment of cancer are the most common causes. There are various other substance that may cause drug-induced mouth ulcers.


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)

Related Articles

  1. Stomatodynia (Mouth Pain)
  2. Stomatorrhagia (Mouth Bleeding)
  3. Mouth Problems

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