What Is Allergic Contact Stomatitis?
Allergic contact stomatitis (ACS) is a type 4 hypersensitivity reaction that is characterized clinically by oromucosal inflammation. This specifically is a contact allergy reaction of the oral mucosal membrane or the oral cavity in patients who have already been sensitized to the allergen (the cause). This is an allergic phenomenon in which the patient does not know they are suffering from this immunotoxicity until several hours or probably days after developing a response to the allergen that has caused the oral pathologic cascade.
It may, in medical terminology, be classified under a form of delayed hypersensitivity or type 4 hypersensitivity reaction to the allergen that usually occurs in 2 phases, namely the induction phase (that the immune system gets sensitized towards the allergen, which is the initiator of the immunologic response) and the second phase (or rather the triggering of immunotoxic reactions) called the effector phase.
Though ACS is a comparatively less common phenomenon than contact dermatitis (the most immunotoxic response observed usually), it affects only a small proportion of individuals. This may be the reason why this allergic phenomenon is not widespread across dental literature. However, the substances commonly used by the dental surgeons or the dental laboratories are used judiciously and with an in-depth knowledge of their action (by virtue of educational training) on the oral cavity by the dental community (the dental surgeons, technicians, and hygienists). Hence, ACS is more often dependent on the individual patient's sensitization and immune response towards a particular compound or substance rather than iatrogenic errors or medical negligence.
How Is Allergic Contact Stomatitis Manifested?
The allergens or irritant compounds or substances can potentially sensitize the oral mucosa causing local itching, burning, erythema, or fissuring only at a specific area of the oral mucous membranes or in a specific portion affected in the oral cavity. Ulcerations, erosions, small blisters at the affected site (mostly found on the sides of the tongue, the gingiva, the cheek mucosa, and the hard palate) may be other clinical presenting features of ACS. Pain, burning sensation, inflammation, or difficulty in chewing and swallowing may be a common chief complaint in patients who suffer from ACS.
What Causes Allergic Contact Stomatitis?
A wide range of substances can trigger a hypersensitivity reaction, which ranges from oral compounds or aromatic substances to everyday consumables like soft drinks, mouthwashes, flavored foods, or candies. The reason why these aromatic compounds trigger the reaction may be due to the higher or the varied concentration present in the consumable item, food, or drink.
The substances usually identified in causing contact stomatitis are mainly:
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Essential oils (Cinnamon oil, spearmint oil, menthol oil, carvone, etc.).
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Acrylates or denture acrylics (used for dental dentures).
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Mercury of dental amalgam.
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Metallic components like nickel, palladium, or gold (Palladium or nickel sensitivity is very commonly identified by dental personnel).
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Lichenoid contact allergy.
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Formaldehyde.
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Flavoring agents or compounds.
What Is the Differential Diagnosis of Allergic Contact Stomatitis?
Plasma Cell Gingivitis: Plasma cell gingivitis is a specific form of contact stomatitis that may be caused explicitly by cinnamon, cinnamon flavor, cinnamaldehyde, or even allergens from certain dentifrices, toothpaste, or mouthwashes. Though this condition is rare compared to the overall incidence of contact stomatitis or contact dermatitis, the massive and diffuse plasma cell infiltration into the connective tissues causes lip swelling and gingival swelling, specifically with glazed plaque-like erythematous surfaces.
The conditions for differential diagnosis of contact stomatitis that the dentist should consider are:
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Contact urticaria.
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Oral allergy syndrome or Pollen Food allergy syndrome.
Both these conditions are acute in nature and not a form of delayed hypersensitivity allergic reaction. These two conditions are examples of type 1 hypersensitivity reactions that occur usually in response to an allergen, in an acute period, say in about 15 to 30 minutes approximately.
How Is Allergic Contact Stomatitis Diagnosed?
The dental surgeon can advocate biopsy obtained from the oral mucous membrane to differentiate the ACS lesion from other oral white and red lesions like oral cancer, oral thrush or candidiasis, oral lichen planus (OLP), leukoplakia, or traumatic lesions of the oral cavity.
The distinguishing component of ACS is that clinical or histopathologic diagnosis is often difficult until the causative agent is removed or refrained after a known or suspected allergic reaction. Hence, an increased histologic view of infiltrated plasma cells indicates contact allergy or plasma cell gingivitis.
The patch testing of the individual for known or dental allergen compounds proves helpful in diagnosing ACS. Positive patch-tested individuals presenting with oral mucosal lesions, burning sensation, or inflammation can present a clinically relevant situation to the dental surgeon or the dental personnel. They have the expertise of identifying the allergen causing ACS. Removing the offensive allergen or the agent detected by patch test will help the dental surgeon use alternative material to finish their clinical or surgical work in the patient's oral cavity. Replacement materials may, in fact, be the simplest way to counteract ACS by the dentist, after a known or observed case of patient allergy.
How Is Allergic Contact Stomatitis Managed by a Dental Surgeon?
The dental surgeon and the personnel should be aware of the risk of hand dermatitis by certain materials (specific individuals allergic to polymers, latex, etc.). They should refrain from using it in the patient's oral cavity if they suffer from it. The dentist should first replace the previously used or outdated materials like gold and nickel restorations or amalgam restorations that has caused the allergy. In the case of acrylic monomers causing contact stomatitis by dentures, prolonged curing of acrylates and more boiling time for dentures can help the patient manage the dentures without other allergies.
As mentioned previously, more often, contact stomatitis is resolved on refraining from the material or substance which can be a dental material, flavoring agent or aromatic compound, food preservatives, hygiene products, or metallic components that has previously caused allergy to the patient. Though topical gel application of intralesional corticosteroid or antiseptic will often prove helpful, systemic administration of non-steroidal anti-inflammatory drugs (NSAIDs), immunosuppressive therapy, and corticosteroids may be needed in chronic or severe cases of ACS.
Conclusion
To conclude, awareness of both the dental surgeon and the patient in the timely identification and elimination of the allergen causing contact stomatitis is beneficial in preventing future relapse of this condition. Certain oils, metals, and even dental materials are capable of evoking such allergic forms of reaction in the oral mucosa. The treatment strategy is designed taking into account the patient's extend of manifestations and degree of involvement. NSAIDs often aids in tackling the inflammatory signs and associated discomfort.
