OBJECTIVE: Dental materials and oral hygiene products may be responsible for oral contact allergic reactions. We aimed to determine the occurrence of allergies in patients with symptomatic oral lichen planus (OLP), oral lichenoid lesions (OLLs) and stomatitis and investigate if patch testing could identify contact allergies to dental materials and oral hygiene products in these patients. METHODS: Forty-nine patients (7 men, 42 women) aged 31 to 77 years (61 ± 10.3 years) with symptomatic OLP, OLL or stomatitis and 29 healthy age- and gender-matched control subjects were included. They underwent an interview, clinical examination, oral mucosal biopsy and epicutan testing to the European baseline series, a toothpaste and dental material series. RESULTS: Nineteen patients had OLP, 19 OLL and 11stomatitis. Oral burning/itching was the most common symptom (83.7%), and 65.3% patients had more than one symptom. Patients visited their dentist more often than the healthy subjects and had statistically higher DMF-T and DMF-S scores. Nineteen patients (38.8%) and 10 healthy control subjects (34.5%) had allergic contact reactions primarily to fragrance ingredients. No differences could be found between OLP, OLL, stomatitis and healthy controls with regard to allergic contact reactions. However, contact allergy to aroma substances differed significantly between the patients and the healthy control subjects (p = 0.02). This type of contact allergy was most common in patients with OLP and OLL (p = 0.01). Avoidance cleared symptoms in all cases. CONCLUSION/CLINICAL RELEVANCE: Allergic reactions to aroma substances in oral hygiene products are common in patients with symptomatic OLP, OLL and stomatitis.