Etiology and Pathogenesis of Oral Adverse Drug Reactions^1-3

Although the skin is more commonly involved in adverse reactions to drugs, the oral mucosa is also frequently affected.  Virtually any drug has the potential to cause an untoward reaction, but some have a greater ability to do so than others.  Pathogenesis of drug reactions may be related to either immunologic or nonimmunologic mechanisms.  Most adverse reactions to drugs are mediated by the immune system and are drug allergies.  Three mechanisms have been proposed for drug allergies.  Firstly, IgE-mediated reactions occur when the drug reacts with IgE antibodies bound to mast cells.  Secondly, drug allergies can involve a cytotoxic reaction in which an antibody binds to a drug that is already attached to a cell surface.  The third mechanism in a drug allergy involves circulation of the antigen for extended periods allowing sensitization of the patient’s immune system and production of a new antibody.  Nonimmunologic drug reactions are not antibody dependent and may directly affect mast cells causing the release of chemical mediators.  Also some nonimmunologic drug-induced reactions result from a drug overdose or toxicity.

Clinical Features of Oral Adverse Drug Reactions^1,2

Manifestations of drug reactions are dependent on the type of drug, drug dose, and individual patient differences.  These reactions can be seen either rapidly or several days after drug use.  Acquired angioedema is an IgE-mediated drug allergy that is commonly observed as drug and food reactions.  Other cutaneous manifestations of drug reactions include urticaria, maculopapular rash, erythema, vesicles, ulcers, and target lesions.  An unusual form of drug reaction is known as fixed drug reaction during which an erythematous lesion appears in the same location with each antigenic challenge.  Oral manifestations of drug reactions may be erythematous, vesicular, or ulcerative in nature.  They may also mimic erosive lichen planus known as lichenoid drug reactions.

Histopathology of Oral Adverse Drug Reactions^1,2

Histologic features or findings of drug reactions include nonspecific features as spongiosis, apoptotic keratinocytes, lymphoid infiltrates, eosinophils, and ulceration.  Also, mononuclear or polymorphonuclear infiltrations in a subepithelial or perivascular distribution, basal cell destruction, edema, and keratinocyte necrosis are seen.

Diagnosis of Adverse Drug Reactions^1,2

The diagnosis of drug reactions requires a high index of suspicion and careful history taking.  Recent use of a drug is important.  Withdrawal of the suspected drug should result in improvement, and reinstitution of the drug should exacerbate the patient’s condition.  The clinical expression of lesions in drug reactions is generally allergic in nature that can help with the diagnosis.

Click Here To Navigate Within Article >> Abstract Etiology and Pathogenesis of Oral Adverse Drug Reactions Effects of Drugs on Oral Mucosa and Tongue Aphthous Stomatitis Glossitis Oral Ulceration Lichenoid Eruptions Color Changes of Oral Mucosa and Teeth Black Hairy Tongue (Lingua villosa nigra) Drug Induced Gingival Hyperplasia Salivary Glands Effects on Dental Structure Taste Disturbance Halitosis Alveolar Osteitis (Dry Socket) Stomatodynia Conclusion References About the Authors
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Citation Number: Vol. 4, No. 1, Page 011