Systemic associations of oral lichen planus and oral lichenoid lesions, a retrospective case-control study of 301 patients

Objective

The objective of this study was to evaluate the association between oral lichen planus (OLP)/oral lichenoid lesions (OLL) and other comorbidities, especially thyroid gland diseases and in addition, the risk of oral squamous cell carcinoma (OSCC).

Material and methods

We performed a retrospective case-control study by using medical data of 301 OLP/OLL patients and 301 age- and sex-matched controls who had visited Kuopio University Hospital (KUH), Finland between years 1996 and 2017. The medical history, the use of regular medications, allergies, presence of LP elsewhere in the body and clinical features of OLP/OLL lesions were registered. In addition, we studied how many of OLP/OLL patients developed a OSCC after at least a 6-year follow up time.

Results

The prevalence of autoimmune hypothyroidism (HT) was 12.2% in OLP group, 18.8.% in OLL group and 9% (n=27) in the control group; the estimated odds ratios being 1.425 [95% CI 0.793 to 2.562] for OLP and 2.292 [95%CI 1.175 to 4.47] for OLL. Patients with HT had more often erosive mucosal lesions compared to patients without HT. Allergies were seen in 32.9% (n=99) of OLP/OLL cases and in 22.9% (69) of controls; the estimated odd ratio being 1.726 (1.184 to 2.516) for OLP/OLL. 6 of 205 OLP patients (3%) and 5 of 96 OLL patients (5.2%) developed OSCC. Most of the OSCCs (4/6) were located in the tongue in OLP group and in OLL group the cancers were randomly distributed.

Conclusions

This study confirms the previously seen association of OLP/OLL and thyroid diseases, especially hypothyroidism. In this study OLL was more strongly associated with HT than OLP. In addition, an association was seen between OLP/OLL and allergies. OLP and especially OLL increase the risk of OSCC.