Oral Lichen Planus and Lichenoid Lesions: Etiopathogenesis, Diagnosis and Treatment

Foreword
Contents
1: Introduction
	References
2: Epidemiology
	References
3: Aetiology
	3.1	 Factors of Exogenous Origin
		3.1.1	 Infectious Agents
		3.1.2	 Factors Causing Lichenoid Reactions
		3.1.3	 Habits and Trauma Factors
	3.2	 Factors of Endogenous Origin
		3.2.1	 Genetic Factors
		3.2.2	 Autoimmunity
		3.2.3	 Heat Shock Proteins (HSPs)
		3.2.4	 Psychological Disorders’ Correlation with OLP
		3.2.5	 Correlation with Other Systemic Diseases
	References
4: Pathogenesis
	4.1	 Cells Involved in the Pathogenesis of OLP
		4.1.1	 Oral Keratinocytes
		4.1.2	 Antigen-Presenting Cells (APCs) and Humoral Immunity
		4.1.3	 T lymphocytes and Apoptosis
		4.1.4	 Natural Killer (NK) Lymphocytes
		4.1.5	 Mast Cells (MCs)
	4.2	 Pathogenic Hypotheses of the OLP
		4.2.1	 Sugerman’s Unifying Hypothesis
		4.2.2	 Modificate Hypothesis of Carrozzo
	4.3	 Soluble Factors Involved in the OLP Pathogenesis
		4.3.1	 Cytokine
		4.3.2	 Chemokine
		4.3.3	 Matrix Metalloprotease (MMP)
		4.3.4	 Role of OLP Immunopathogenesis in Response to Therapy
	4.4	 Other Factors Involved in the Pathogenesis of OLP
		4.4.1	 Micro-RNA (mi-RNA or miR)
		4.4.2	 Vitamin D (VIT.D)
		4.4.3	 Beta-Defensin
		4.4.4	 Histamine
		4.4.5	 Other Factors
	4.5	 Pathogenesis Related to the Malignant Transformation OF OLP, Prognosis, and Follow-Up
		4.5.1	 Epidemiology of Neoplastic Risk in OLP
		4.5.2	 Characteristics of Carcinoma Arising from the OLP Lesion
		4.5.3	 Pathogenetic Mechanisms of the Transformation Neoplastic OLP
		4.5.4	 Genetic Alterations Related to the Malignant Transformation of OLP
		4.5.5	 Prognosis and Follow-Up of OLP
	References
5: Diagnosis
	5.1	 Clinical Classification of OLP Lesions
		5.1.1	 Papular OLP
		5.1.2	 Reticular OLP
		5.1.3	 Plaque OLP
		5.1.4	 Atrophic-Erythematous OLP
		5.1.5	 Erosive and Ulcer-Erosive OLP
		5.1.6	 Bullous OLP
		5.1.7	 Mixed and Atypical OLP
	5.2	 Histopathology of OLP Lesions
	5.3	 Diagnostic Criteria and Definitive OLP Diagnosis
		5.3.1	 WHO Criteria (1978)
		5.3.2	 van der Meij and van der Waal Modified Criteria (2003)
		5.3.3	 American Academy of Oral and Maxillofacial Pathology Criteria (2016)
		5.3.4	 Updated WHO Criteria (2020)
	5.4	 Additional Investigations in the Diagnosis of OLP
		5.4.1	 Direct Immunofluorescence (DIF)
		5.4.2	 Indirect Immunofluorescence (IIF)
		5.4.3	 Other Investigations and Biomarkers
	5.5	 Differential Diagnosis
		5.5.1	 Specific and Non-specific OLP Characteristics
		5.5.2	 Oral Lichenoid Contact Lesions (OLCLs or OLCHR)
		5.5.3	 Oral Lichenoid Drug Reactions (OLDRs)
		5.5.4	 OLL Related to Graft-Versus-Host Disease (OLL-GvHD)
		5.5.5	 Dental and Pharmacological Management of OLL/OLP
		5.5.6	 Pemphigus Vulgaris
		5.5.7	 Bullous Pemphigoid (BP)
		5.5.8	 Lichen Planus Pemphigoides (LPP)
		5.5.9	 Mucous Membrane Pemphigoid (MMP)
		5.5.10	 Lichen Planus-Like Variant of Paraneoplastic Pemphigus (PNP)
		5.5.11	 Chronic Ulcerative Stomatitis (CUS)
		5.5.12	 Erythema Multiforme (EM)
		5.5.13	 Discoid Lupus Erythematosus (DLE)
		5.5.14	 Systemic Lupus Erythematosus (SLE)
		5.5.15	 Leukoplakia and Erythroplakia (LK, ELK, EK, PVL)
		5.5.16	 Proliferative Verrucous Leukoplakia (PVL)
			5.5.16.1 Lichenoid Dysplasia (LD)
			5.5.16.2 Other Oral Lichenoid Lesions
			5.5.16.3 Summary and Final Considerations
	References
6: Therapy
	6.1	 Glucocorticoids
		6.1.1	 Systemic Glucocorticoids
		6.1.2	 Topical Glucocorticoids
	6.2	 Immunomodulating Agents
		6.2.1	 Calcineurin Inhibitors
		6.2.2	 Analogues of the Synthesis of Purine and Pyrimidine Bases
		6.2.3	 mTOR Inhibitors
		6.2.4	 NF-κB Inhibitors
		6.2.5	 Antibiotics
		6.2.6	 Antimicotics
		6.2.7	 Antiprotozoals
		6.2.8	 Anti-Welmintics
		6.2.9	 Other Immunomodulating Agents
	6.3	 Vitamin Complexes
		6.3.1	 Retinoids (Vitamin A)
		6.3.2	 Group B Vitamins
		6.3.3	 Vitamin D
		6.3.4	 Tocopherol (Vitamin E)
		6.3.5	 Flavonoids (Vitamin P)
	6.4	 Nutraceuticals
		6.4.1	 Oral Curcuminoids
		6.4.2	 Aloe Vera (AV)
		6.4.3	 Hyaluronic Acid (HA)
		6.4.4	 Green Tea
		6.4.5	 Propolis
		6.4.6	 Chamomile
		6.4.7	 Glycyrrhizin
		6.4.8	 Eiconol
		6.4.9	 Selenium
		6.4.10	 Ignatia
		6.4.11	 Portulaca Extract
		6.4.12	 Total Glucosides of Paeony (TGP)
		6.4.13	 Piperine
	6.5	 Monoclonal Antibodies
		6.5.1	 Anti-TNF-α
		6.5.2	 Anti-IL-2R
		6.5.3	 Anti-CD11a
		6.5.4	 Anti-CD2
		6.5.5	 Anti-CD20
		6.5.6	 Anti-VEGF
		6.5.7	 Other Monoclonal Antibodies
	6.6	 Non-pharmacological Therapy
		6.6.1	 Psychiatric Therapy
		6.6.2	 Bacillus Calmette-Guerin Polysaccharide Nucleic Acid (BCG-PSN)
		6.6.3	 Platelet-Rich Plasma (PRP)
		6.6.4	 Conventional Surgery
		6.6.5	 Cryotherapy
		6.6.6	 Phototherapy
		6.6.7	 Final Considerations
	References