**8. Clinical manifestations of OLP**

The diagnosis of OLP is usually made on clinical features alone. However, careful attention to the clinical history is essential, to ensure assessment, and if warranted, the appropriate management, of the extra-oral manifestations of lichen planus. [1, 32, 33]

OLP is classified morphological into seven different clinical presentations: Predominantly white, usually slightly raised lesions consisting of a (1) reticular form (2) papular, and (3) plaque-form seen in about 23% of patients, [34, 35] the predominantly erythematous presen‐ tations, with (4) atrophic mucosa, which is seen in some 40% of patients, (5) ulcerative (erosive) lichen planus, seen in some 37% of presenting patients and the rare (6) vesiculo-bullous form (Figures 2a – 4b). [2] In some 10% of patients have their OLP confined to the gingivae, termed (7) "desquamative gingivitis". This term is a clinical descriptor, used to describe inflammation, with a mix of erythema, erosion and/or ulceration of the gingival tissues and the immediately adjacent alveolar mucosa, not incited by the presence of dental bacterial plaque (Figures 5a and 5b). These latter predominantly erythematous forms of OLP can be associated with significant discomfort requiring either topical and/or systemic immunosuppressive therapy. [33] When patients do present with pain, it usually is not spontaneous, but they tend to complain of mild, but noticeable intolerance to particularly salty, spicy or acidic foods (such as any form of curry) brushing of their teeth, which can be made worse and is generalised, on the use of flavoured toothpastes. Rarely, patients will present with widespread oral mucosal ulceration that is spontaneously very painful and so elicit their presentation. The asympto‐ matic, predominantly white appearing, striated, papular and plaque forms of OLP tend to be found incidentally during the course of an oral examination. They commonly take the form of minute white papules that gradually enlarge and coalesce to form either a reticular, annular, or plaque-like pattern. A characteristic feature is the presence of slender white lines (Wick‐ ham's striae) radiating from the papules. In the reticular form, there is a lace-like network of slightly raised white lines, often interspersed with papules or rings. The plaque-like form may be difficult to distinguish from leukoplakia. Oral lesions of lichen planus may also include bullae, but this is rare. These different forms can merge or coexist in the same patient. [1, 34, 35] The commonest sites are inevitably bilateral and include the buccal mucosa (seen in some 90% of patients), gingiva, dorsal tongue, lateral tongue, labial mucosa and the lower lip. Uncommon sites include the palate (Figure 6), upper lip, and floor of the mouth. [34] The gingivae are commonly the site of erythematous/erosive OLP. Involvement of the gingivae is described clinically as desquamative gingivitis, but is not unique to OLP and may feature in the presentation of other oral dermatoses, especially pemphigoid and pemphigus. [34]

**Figure 2.** a) Reticular OLP (tongue); b) Reticular OLP (buccal mucosa)

**Figure 3.** Paupular OLP

DR6. in those patients who also have HCV. [31] To date no specific HLA antigen profile has

In summary, despite the oral mucosa only being capable of a limited immunological response, the immuno-pathogenesis of OLP is complex. OLP appears to be predominantly a delayedtype IV hypersensitivity reaction, due in large measure to cytotoxic CD8+ T-lymphocyte induced apoptosis of the basal keratinocytes of the oral epithelium. There are also a number of aspects, best characterised as immune-deregulation that leads to a self -inducing, selfperpetuating cycle that may explain the chronicity of OLP. However, despite a limited comprehension of the pathogenesis of OLP, therapeutic stratagems are being pursued, based on this understanding, including the trialling of TNF-α inhibitors, interleukin-1 inhibitors, mast cells stabiliser agents, to prevent their degranulation, and the use of agents that can induce the up-regulation of key immune-suppressive cytokines such as TGF-β and interleukin-8, or

The diagnosis of OLP is usually made on clinical features alone. However, careful attention to the clinical history is essential, to ensure assessment, and if warranted, the appropriate

OLP is classified morphological into seven different clinical presentations: Predominantly white, usually slightly raised lesions consisting of a (1) reticular form (2) papular, and (3) plaque-form seen in about 23% of patients, [34, 35] the predominantly erythematous presen‐ tations, with (4) atrophic mucosa, which is seen in some 40% of patients, (5) ulcerative (erosive) lichen planus, seen in some 37% of presenting patients and the rare (6) vesiculo-bullous form (Figures 2a – 4b). [2] In some 10% of patients have their OLP confined to the gingivae, termed (7) "desquamative gingivitis". This term is a clinical descriptor, used to describe inflammation, with a mix of erythema, erosion and/or ulceration of the gingival tissues and the immediately adjacent alveolar mucosa, not incited by the presence of dental bacterial plaque (Figures 5a and 5b). These latter predominantly erythematous forms of OLP can be associated with significant discomfort requiring either topical and/or systemic immunosuppressive therapy. [33] When patients do present with pain, it usually is not spontaneous, but they tend to complain of mild, but noticeable intolerance to particularly salty, spicy or acidic foods (such as any form of curry) brushing of their teeth, which can be made worse and is generalised, on the use of flavoured toothpastes. Rarely, patients will present with widespread oral mucosal ulceration that is spontaneously very painful and so elicit their presentation. The asympto‐ matic, predominantly white appearing, striated, papular and plaque forms of OLP tend to be found incidentally during the course of an oral examination. They commonly take the form of minute white papules that gradually enlarge and coalesce to form either a reticular, annular, or plaque-like pattern. A characteristic feature is the presence of slender white lines (Wick‐ ham's striae) radiating from the papules. In the reticular form, there is a lace-like network of slightly raised white lines, often interspersed with papules or rings. The plaque-like form may

the *in-vitro* production of these cytokines for use as therapeutic agents.

management, of the extra-oral manifestations of lichen planus. [1, 32, 33]

been found associated with idiopathic OLP.

156 Skin Biopsy - Diagnosis and Treatment

**8. Clinical manifestations of OLP**

OLP not only tends to develop in sites of trauma (Koebner phenomenon) but tends to be exacerbated by mechanical factors including biting/chewing habits, dental procedures and

Oral Lichen Planus

159

http://dx.doi.org/10.5772/56482

**Oral Lichen Planus (OLP):** in which patients present with oral lichenoid lesions not readily attributable to any defined cause, that is to say "idiopathic" OLP. OLP represents one aspect of the spectrum of mucocutaneous lichen planus, which can affect potentially any mucosal

**Oral Lichenoid Contact Lesions (OLCL):** due to allergic contact stomatitis (delayed immune mediated hypersensitivity) and seen in direct topographic relationship to dental restorative

**Oral Lichenoid Drug Reactions (OLDR:** in which oral and/or cutaneous lesions occur, temporally associated with the taking of certain medications, such as oral hypoglycaemic drugs, angiotensin converting enzyme (ACE) inhibitors, and non-steroidal anti-inflammatory agents (NSAIDS), but historically has been seen with the previous more wide-spread use of

**Oral Lichenoid Lesions of Graft versus Host Disease (OLL-GVHD):** in the setting of patients

gold salts and penicillamine for the management of rheumatoid arthritis. [38]

with acute, but predominantly, chronic graft versus host disease (cGVHD). [33]

rubbing of malpositioned or ill-fitting dentures, teeth and fillings.

Oral lichenoid reactions encompass several clinical entities. [33-36]

**9. Clinical subtypes of oral lichenoid reactions**

surface, and/or the skin and its appendages.

materials, most commonly amalgam (Figure 7). [36, 37]

**Figure 7.** Oral Lichen Contact Lesion (OCLC) – left buccal mucosa

**Figure 4.** a) Ulcerative (erosive) OLP (dorsal tongue); b) Ulcerative (erosive) OLP (buccal mucosa)

**Figure 5.** a) Desquamative gingivitis; b) Desquamative gingivitis with plaque form of OLP of central lower lip

**Figure 6.** OLP of the hard palate

OLP not only tends to develop in sites of trauma (Koebner phenomenon) but tends to be exacerbated by mechanical factors including biting/chewing habits, dental procedures and rubbing of malpositioned or ill-fitting dentures, teeth and fillings.
