Possible link between Hashimoto's thyroiditis and oral lichen planus: a novel association found

Abstract

Objectives Hashimoto's thyroiditis as well as lichen planus has been associated to a number of disorders, generally of auto-immune origin. A novel possible association between oral lichen planus (OLP) and Hashimoto's thyroiditis (HT) is here proposed on the basis of a cross-sectional survey. Materials and methods One hundred and five unrelated OLP patients were considered. Diagnosis of HT was based on positive serum anti-TPO, anti-Tg, TSH levels and the typical ultrasound pattern of the thyroid gland. Results In the present survey, the prevalence of HT in the OLP group was 14.3 % whereas the prevalence of HTrelated hypothyroidism in the general population was reported to be equal to 1 %. By Fisher's exact test, it was revealed that the difference between our data and historical prevalence of HT was found statistically significant. Conclusion Actually, there is no definitive hypothesis that could explain the coexistence of OLP and HT. However, considering the onset timing of HT followed by OLP in 93.3 % of our series, we suspected a causal or predisposing role for HT. Specifically, we believe that in HT patients, circulating thyroid antibodies could contribute to trigger an organ-specific auto-immune response also in the oral mucosa or skin, leading to the development of LP lesions. Clinical relevance Because of the large number of cases of asymptomatic chronic auto-immune thyroiditis, it would be useful that women over 40 years of age affected by OLP were screened for thyroid dysfunction, particularly HT.

Association of Oral Lichen Planus with Autoimmune Diseases in A Northern Serbia Population: Matched Case-Control Study and Literature Review

“…A novel possible association between OLP and thyroid gland diseases (Hashimoto's thyroiditis) has been proposed recently on the basis of cross-sectional, case-control studies similar to our [11,12]. A very similar odd ratio estimates were found by Siponen et al [11] for the associacion of any thyroid diseases and OLP, particularly with hypothyroidism.…”

“…All of the OLP patients in the present study with the coexistence of Hashimoto thyroiditis and all but one in recently reported [12] were female gender. Most autoimmune diseases occurs significantly more frequently in women than men, especially Hashimoto's thyroiditis and Grave's disease, with a female to male ratio of 50:1 and 7:1 respectively [42,43].…”

“…However, an interesting fact is that few other recent studies from different parts of the world have reported similar results that highlight connection between lichen planus and thyroid gland disorders [9][10][11][12][13]. Since many autoimmune diseases showed primary signs in the mouth detailed clinical examination of oral mucosa in asymptomatic patient could be the best opportunity for early diagnosis of autoimmune disease.…”

“…In contrast, some authors based on a crosssectional study performed in Sicily (West Mediterranean area) have denied an association between OLP and hypothyroidism [26]. Lo Muzio et al [12] pointed out that there is no definitive hypothesis that could explain the coexistence of OLP and Hashimoto's thyroiditis. However, considering the onset timing of Hashimoto's thyroiditis followed by OLP in 93.3 % of them and in all of our series, Hashimoto's thyroiditis may have trigger or predisposing role.…”

“…A positive connection between OLP and certain systemic diseases have been reported in the past, such as diabetes [4,5], arterial hypertension [6], infection with hepatitis C (HCV) [7], and malignant diseases [8].The association between OLP and other autoimmune diseases has been a subject of ongoing research, although studies qualify these associations with scarce. Furthermore, over the last 5 years in various populations a novel possible association between OLP and thyroid diseases has been described [9][10][11][12][13]. Previous research has also produced some evidence of a higher frequency of some diseases, generally of autoimmune origin among OLP patients than among the general population (myasthenia gravis, vitiligo, alopecia areata, thymoma, ulcerative colitis, psoriasis, celiac disease, Sjögren's syndrome and rheumatoid arthritis).…”