Dermatology Al Azhar University Gaza

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PAPULOSQUAMOUS DISEASES
CUTANEOUS AND ORAL
LICHEN PLANUS
Etiology and Pathogensis:
 The etiology of OLP is not known. During many years, it has become evident that the
immune system has a primary role in the development of this disease. The cell-mediated
arm of the immune system is involved in the pathogenesis of OLP through T-lymphocyte
cytotoxicity directed against antigens expressed by the basal cell layer.
 Other factors, such as stress, may also be of importance to establish this inflammatory
process. Altogether, this makes the etiology behind OLP a multifactorial process comprising
events that may take place at different time points and therefore difficult to investigate.
 Associated conditions:
 An association between OLP and hepatitis C virus (HCV) has been described.
 Other conditions: Diabetes mellitus especially in oral LP, underlying malignancy and
autoimmune diseases e.g ulcerative colitis [*].
Epidemiology:
In the literature, different prevalence figures for OLP have been reported and vary from 0.5%–
2.2%. The mean age at the time of diagnosis is approximately 55 years.
Clinical Findings:
 Oral lichen planus:
OLP may contain both red and white elements that can be a part of the following clinical types:
•• Reticular
•• Papular
•• Plaque-like
•• Bullous
•• Erythematous
•• Ulcerative
To establish a clinical diagnosis of OLP, reticular or papular textures have to be present. The
explanation of the different clinical manifestations of OLP is presumably related to the magnitude
of the subepithelial inflammation. An inflammatory gradient may be formed where the central
part comprises an intense inflammatory process, whereas the periphery is less affected.

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 The reticular form of OLP is characterized by fine white lines or striae that may form a network
[ lace like] but can also show annular (circular) patterns. The striae often display a peripheral
erythematous zone, which reflects a subepithelial inflammation. Site: Although reticular OLP
may be encountered in all regions of the oral mucosa, most frequently this form is observed
bilaterally in the buccal mucosa and rarely on the mucosal side of the lips. Reticular OLP can
sometimes be observed at the vermilion border.
 The papular type of OLP is usually present in the initial phase of the disease. It is clinically
characterized by small white dots, which in most occasions intermingle with the reticular
form. Sometimes the papular elements merge with striae as part of the natural course.
 Plaque-type OLP shows a homogeneous well-demarcated white plaque that occurs in
conjunction with striae. Plaque-type lesions may clinically be very similar to homogeneous oral
leukoplakias. The difference between these two mucosal disorders is the presence of reticular or
papular structures in the case of plaque-like OLP. The form is most often encountered in
smokers and following cessation, the plaque may disappear and convert into the reticular type
of OLP. Some scientific reports lend support to the premise that plaque- like OLP is
overrepresented among OLP lesions transforming into oral squamous cell carcinomas.
Typically, the reticular, papular, and plaque-like forms of OLP are asymptomatic, although the
patient may experience a feeling of roughness.
 The bullous form is very unusual but may appear as bullous structures surrounded by a
reticular network.
 Erythematous (atrophic) OLP is characterized by a homogeneous red area. When this type of
OLP is present in the buccal mucosa or in the palate, striae are frequently seen in the periphery
of the lesion.
Some patients may display erythematous OLP exclusively affecting attached gingiva. This
form of lesion may occur without any papules or striae and presents as desuamative gingivitis.
Therefore, erythematous OLP may require a histopathologic examination in order to arrive at a
correct diagnosis.
 Ulcerative lesions are the most disabling form of OLP. Clinically, the fibrin-coated ulcers are
surrounded by an erythematous zone with white striae in the periphery. This appearance may
reflect a gradient of the intensity of subepithelial inflammation that is most prominent at the
center of the lesion. As for the erythematous form of OLP, the affected patient complains of a
smarting sensation in conjunction with food intake.
 Extraoral LP:
1. Cutaneous lesions: may be encountered in approximately 15% of patients with OLP. The
classic appearance of skin lesions consists of [ 6 P’s: planer (flat topped), pruritic,
polygonal, purple, polished (shiny) papules *], pruritic erythematous to violaceous papules
that are flat topped and their surface shows fine white dots or lines [Wickham striae*]. The
predilection sites are the trunk and flexor surfaces of arms and legs. The papules may be
discrete or coalesce to form plaques. The patients report relief following intense scratching

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(rubbing rather than actual scratching) of the lesions, but trauma may aggravate the
disease, which is referred to as a Koebner phenomenon (Koebner phenomenon : is
appearance of pathological isomorphic lesion in traumatized uninvolved skin). This
phenomenon may also be of relevance for OLP, which is continuously exposed to physical
trauma during mastication and tooth brushing.
2. The most frequent extra-oral mucosal site involved is the genital mucosa. Close to 20% of
women presenting with OLP also have genital involvement. Symptoms including burning,
pain, vaginal discharge, and dyspareunia are frequently noted in patients with the
erythematous or ulcerative forms of the disease [and is called vulvovaginal–gingival (VVG)
syndrome*]. No relationship seems to exist between the degree of severity in the oral and
genital sites. Genital lichen planus has been reported in males, but the association with OLP
is not as frequent as for women. Esophageal lichen planus has been described to occur
simultaneously with OLP in some patients, the main complaint being dysphagia.
3. Hair: cicatricial alopecia (scar area with permanent destruction of hair follicles)[*].
4. Nail: Nail changes are present in approximately 5–10% of patients. It can occur as an initial
manifestation, especially in children. Longitudinal ridging, splitting and Onycholysis.
Involvement of the entire matrix may lead to obliteration of the whole nail plate
(anonychia). Pterygium formation is very characteristic of LP of the nails in which the nail
matrix is destroyed by the inflammation and replaced by fibrosis. The proximal nailfold
fuses with the proximal portion of the nailbed. LP may be a cause of some cases of twenty-
nail dystrophy of childhood [*]
Diagnosis of OLP:
Papules or reticular components have to be present in order to establish a correct clinical
diagnosis. These pathognomonic components may exist together with plaque-like, erythematous,
bullous, or ulcerative lesions. In patients with gingival erythematous lesions, it may be difficult to
find striae or papules. A biopsy is usually required for an accurate diagnosis of this type of OLP.
Differential diagnosis:
1. Lupus erythematosus (LE) shows white radiating striae sometimes. It is differentiated
from LP by histopathology and lupus band test.
2. Plaque-like OLP is discriminated from homogeneous oral leukoplakia as the
latter is not featured with papular or reticular elements.
3. Ulcerating conditions such as erythema multiforme and adverse reactions to
nonsteroidal anti-inflammatory drugs (NSAIDs) may be difficult to distinguish from
ulcerative OLP. The former lesions, however, do not typically appear with reticular or
papular elements in the periphery of the ulcerations.
4. If erythematous and/ or ulcerative lesions are the only presenting lesions, specially on
the gingiva, the differential diagnosis must include all the conditions that lead to
ulcerative gingivitis (desquamative gingivitis) as : (mucous membrane pemphigoid ,

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OLP, vesiculobullous disorders including pemphigus vulgaris and linear IgA disease),
biopsy for both histology and DIF is needed
5. Graft versus host disease.
Pathology:
The histopathologic features of lichen planus are:
1. Areas of hyperparakeratosis, often with focal thickening of the granular cell layer
[focal hypergranulosis (Wickham’s striae)].
2. Irregular acanthosis with a saw-toothed appearance of the rete ridges.
3. Interface dermatitis that includes:
a. Basal cell damage (due to hydropic degeneration or liguifactive degeneration)
forming civate or colloid bodies
b. Bandlike lymphocytic (primarily T-cell) infiltrate in the connective tissue just below
the basement membrane.
c. Melanophages in upper dermis due to pigmentary incontinence
Management:
Since the etiology behind OLP is unknown, basic conditions for development of preventive
therapies are lacking. Thus, all current treatment strategies are aiming at reducing or eliminating
symptoms.
 Several topical drugs have been suggested, including:
 Steroids: primary treatment of choice for symptomatic OLP. Topical steroids used as a
mouth rinse (swish and spit out) or a gel or paste.
 Calcineurin inhibitors (cyclosporine, tacrolimus and pimecrolimus) and retinoids: second-
line therapy for OLP. However, this drug has been labeled with the US Food and Drug
Administration’s Black Box Warning: “Possibility of increased risk of malignancy
(squamous cell carcinoma and lymphoma) in patients using topical tacrolimus/pimecrolimus
for cutaneous psoriasis. These agents should be used in limited circumstances, and patients
made aware of these concerns.
 Ultraviolet phototherapy.
Relapses are common, and the general approach should be to use steroids at the lowest level to
keep the patient free of symptoms.
 Although topical steroids are usually able to keep OLP patients free of symptoms, systemic
steroids are justified to control symptoms from recalcitrant lesions. oral hygiene should be
optimized prior to the beginning of steroid treatment.
OLP is considered to be a premalignant disorder that entail an increased risk of malignant
transformation at some site of the oral mucosa, not necessarily associated with a preexisting

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lesion. It is widely accepted that patients with OLP are predisposed to develop oral carcinomas,
although it should be emphasized that the risk is low and presumably does not exceed an
incidence of 0.2% per year. Albeit the risk for patients with OLP to contract oral squamous cell
carcinomas is low, a minimum of annual monitoring has been suggested in conjunction with
routine dental examination by the general dental practitioner. For patients with symptomatic OLP,
examination for malignancies will be a part of the evaluation of symptomatic treatment. In
countries with limited health-care resources, it may be difficult to conduct annual monitoring, but
at the time of diagnosis, patients need to be properly educated on the subject of the malignant
potential of OLP.
Source:
Burket’s Oral Medicine, 12th edition, Michael Glick.(2015). People’s Medical Publishing House—
USA.p: 104-111

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