About Contact stomatitis

Stomatitis means a sore mouth.  Contact stomatitis a different allergic response occurring in the mouth and sometimes the face area.

What causes contact stomatitis

Contact stomatitis is an uncommon allergic reaction affecting the inside of the mouth caused by contact with an allergen. usually flavorings, metals or other components in oral hygiene products, foods, dental restorations and medications.  It may also be called allergic contact stomatitis to distinguish this form from intraoral irritant reactions.

Contact stomatitis a different allergic response. Often seen as a redness on the tongue or ulcers on the gums

Who gets contact stomatitis and why?

Contact stomatitis is a delayed hypersensitivity (Type IV) reaction to a chemical in contact with the lining of the mouth.  It occurs in people already sensitized to the allergen.  However, it is quite uncommon compared to contact allergic dermatitis or contact cheilitis, probably because:

  1. Saliva constantly flushes the mouth quickly. Thus, allergen chemicals are diluted and do not stay in contact with the mucosa for very long
  2. There is a good blood supply to the lining of the mouth. Therefore any allergen chemicals absorbed through the mucosa are removed from the mouth area
  3. The lining of the mouth is not well keratinised.  Allergen chemicals are less likely to bind to keratin protein to form other allergens.

Rarely, contact urticaria may present as stomatitis.

Which products cause contact stomatitis?

Oral hygiene products


  • Chewing gum
  • Sweets/candies/lollies
  • Foods especially flavored with cinnamon

Dental restorations

  • Orthodontic wires – brackets, bands
  • Dental prostheses – dentures, plates
  • Dental cement
  • Dental restorations
    • Dental amalgam
    • Composite resin
    • Gold

Medications — topical

Major sources of allergens causing contact stomatitis

The following  lists possible chemicals responsible for contact stomatitis.

What are the clinical features of contact stomatitis?

The symptoms and signs of acute contact stomatitis usually develop within hours of contact with the allergen. The chronic form occurs when the allergen is always in the mouth such as with a dental restoration.

All parts of the mouth can be affected. However, the most common sites involved in contact stomatitis are:

  • Sides of the tongue
  • Gums
  • Inside of the cheeks
  • Hard palate.

Contact stomatitis has a number of possible clinical features that may occur in various combinations. These include:

  • Burning
  • Swelling – may mimic contact urticaria or angioedema
  • Redness
  • Cracking
  • Ulcers, erosions – erosive stomatitis
  • Small blisters
  • Peeling
  • White patches or lines
  • Pain.

A lichenoid amalgam reaction is also a form of contact stomatitis and is a type of oral lichen planus.

Plasma cell gingivitis is another specific form of contact stomatitis.

Contact urticaria and oral allergy syndrome are type 1 hypersensitivity reactions and occur and recover more quickly than contact stomatitis.

Diagnosing contact stomatitis

The diagnosis of contact stomatitis is clinical.  Therefore diagnosis are based on history and examination.  Further investigations to exclude other possible diagnoses and to identify the responsible allergen.

A mucosal biopsy may be required to exclude other conditions such as various forms of oral leukoplakia, trauma, oral candidiasis (thrush), oral lichen planus and oral lichenoid drug eruption, lupus erythematosus or discoid lupus, or oral cancer. The histology of contact stomatitis itself is nonspecific. However, the presence of many plasma cells may be suggestive of a contact allergy.

Identification of the allergens

The likely source of the allergen will often be identified on the history and examination with improvement when the source is avoided. Recurrence of the stomatitis following rechallenge with the allergen confirms the cause. Patch testing, including using the patient’s own products, will be helpful in identifying the responsible allergen but false negatives are common. The relevance of a positive patch test reaction must be assessed in the clinical setting.

Treating contact stomatitis

The pattern will depend on what form the allergen is in. For example, if the allergen is in a removable dental prosthesis, the pattern will reflect the shape and area of contact between the prosthesis and the oral mucosa. The reaction may be generalized when due to toothpaste or mouthwash. Stomatitis due to dental restoration or orthodontic devices will be adjacent to the restored tooth or wires.

All parts of the mouth can be affected. However, the most common sites involved in contact stomatitis are:

Meanwhile the source of the allergen will often be identified on the history and examination.  Afterwards improvement will happen when the source antigen is avoided. Recurrence of the stomatitis following rechallenge with the allergen confirms the cause. Patch testing, including with the patient’s own products, may be helpful in identifying the responsible allergen. Although false negatives are common. A positive patch test reaction in the clinical setting, indicates an allergen to remove from your environment.

Treating contact stomatitis

The most important treatment for contact stomatitis is the avoidance of the allergen. If it is due to a flavoring or preservative in food or dental hygiene products. Concurrently, advising the patient to stop using the product is wise.  It may take up to 2 weeks for complete resolution. Additionally, a topical steroid  can treat persistent, severe or chronic reactions.

In one case due to an acrylic monomer in a new denture, prolonged boiling of the denture resulted in full curing of the acrylate and the stomatitis resolved.

Furthermore, examitation of contact stomatitis due to a dental restoration (particularly gold) or orthodontic devices made of (nickel) are a cause. Thus, dental device replacement or correction is a fix.  A contact stomatitis reaction related to site to the restoration/device, along with a positive patch test to the metals (nickel sulphate hexahydrate or gold sodium thiosulphate) indicates an allergic reaction.


  • De Rossi SS, Greenberg MS. Intraoral contact allergy: A literature review and case reports. JADA 1998; 129: 1435–41. PubMed
  • Kind F, Scherer K, Bircher AJ. Allergic contact stomatitis to cinnamon in chewing gum mistaken as facial angioedema. Allergy 2010; 65: 276–7. PubMed
  • Koutis D, Freeman S. Allergic contact stomatitis caused by acrylic monomer in a denture. Australas J Dermatol 2001; 42: 203–6. PubMed
  • Möller H. Dental gold alloys and contact allergy. Contact Dermatitis 2002; 47: 63–6. PubMed
  • Torgerson RR, Davis MDP, Bruce AJ, Farmer SA, Rogers RS III. Contact allergy in oral disease. J Am Acad Dermatol 2007; 57: 315–21. PubMed
  • Tremblay S, Avon SL. Contact allergy to cinnamon: Case report. JCDA 2008; 74: 445–8. PubMed
  • Liviu Feller, Neil Hamilton Wood, Razia Abdool Gafaar Khammissa, Johan Lemmer. Review: allergic contact stomatitis. Pubmed

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