Thyroid Autoimmunity and Lichen.

Area of Science:

• Dermatology and Immunology
• Autoimmune Diseases Research

Background:

• Lichen planus (LP) and lichen sclerosus (LS) are autoimmune-mediated cutaneous-mucous diseases with uncertain prevalence.
• Existing data likely underestimate the true prevalence of LP (0.1-4% cutaneous, 1.27-2.0% oral) and LS (0.1-3.3%).
• The association between lichen diseases and autoimmune thyroid disease (AITD) is noted, especially in females, but requires further clarification.

Purpose of the Study:

• To review the literature on the correlation between lichen planus, lichen sclerosus, and autoimmune thyroid disease.
• To investigate shared genetic risk factors between lichen diseases and AITD.
• To explore potential common pathogenic mechanisms, including molecular mimicry, underlying the co-occurrence of these conditions.

Main Methods:

• Comprehensive literature review of studies examining the association between LP/LS and AITD.
• Analysis of existing research on shared genetic risk factors.
• Synthesis of findings to propose potential common etiological pathways.

Main Results:

• The association between lichen sclerosus and AITD is more established than that for lichen planus.
• In both LP and LS, the co-occurrence with AITD is more frequent in females.
• Evidence suggests shared genetic predispositions and potential common pathogenic mechanisms between lichen diseases and AITD.

Conclusions:

• A common pathogenic mechanism may underlie the co-occurrence of lichen diseases and AITD in certain patient populations.
• Molecular mimicry is proposed as a potential trigger for both lichen diseases and AITD, explaining their simultaneous occurrence.
• Further research is warranted to elucidate the precise interplay between genetic factors and immune responses in these associated autoimmune conditions.