Allergic contact stomatitis associated with toothpaste use in Brazil: a multicenter retrospective case series

Objective: This study describes the clinical features and outcomes of Brazilian patients diagnosed with suspected allergic contact stomatitis (ACS) after using a newly introduced commercial toothpaste formulation. Methods: This multicenter retrospective case series included six patients evaluated between January and May 2025 by Oral Medicine services at four universities. Inclusion criteria comprised clinical signs and/or symptoms compatible with ACS, recent use of a new Colgate-Palmolive toothpaste formulation containing stannous fluoride, and no reported exposure to other allergens. Clinical data retrieved from patient records underwent descriptive analysis. Results: All patients presented acute oral symptoms including burning, pain, dysphagia, and dyslalia. Clinical signs included erythematous macules, white plaques, desquamation, vesicles, erosions and ulcers affecting different oral sites. Lesions resolved within 4 to 29 days after toothpaste discontinuation, with or without pharmacologic intervention. No cases required biopsy or patch testing. In all cases, the temporal relationship and remission following toothpaste withdrawal supported the diagnosis of ACS. Conclusions: This study highlights a potential association between toothpaste formulations and ACS. Given the complexity of toothpaste formulations and the absence of allergological testing, the causative substance remains uncertain. Clinicians should consider ACS in patients presenting with unexplained oral lesions and recent changes in oral hygiene products.