Lichen planus (LP) has also been known as lichen ruber planus. It is one of the most common dermatologic, immunopathological diseases to affect the oral mucous membrane. The management of oral lichen planus continues to challenge even the most experienced oral physician.
The term ‘lichen planus’ is derived from a Greek word lichen which means tree moss and a Latin word planus which means flat. The strange name of the condition was provided by the British physician Erasmus Wilson, who first described the lesion in 1869. Thibierge first described the oral lesions systematically in 1885.
Fitzpatrick et al (1993) described LP as a unique cutaneous entity consisting of an eruption of papules distinct in color and configuration, in patterns and location of appearance and in microscopic as well as gross structure.
An interplay of host, lifestyle, and environmental factors has been implicated in the etiopathogenesis of LP. It is believed that LP is caused due to cell-mediated immunity initiated by endogenous or exogenous factors.
The onset of LP occurs most commonly during the 5th or 6th decade. No sexual predilection is evident. The typical cutaneous lesions of LP present as flat topped, purple, polygonal, pruritic papules and plaques most commonly occurring on the flexor surfaces of the arms, wrists, ankles, and legs.
Oral lesions may be observed in up to 75% of patients with cutaneous LP and in approximately 25% of cases it can be the only manifestation of the disease. Conversely, only 10–20% of patients whose initial presentation is oral LP will develop cutaneous LP. The oral lesions have been observed in up to 1–4% of the population.
Oral LP almost invariably occurs as a bilateral disease and it involves the posterior buccal mucosa followed less commonly by the tongue, gingiva, hard palate, and the labial mucosa. Although any site can be involved, palatal and sublingual lesions are very uncommon.
Clinically oral LP appears as radiating white or gray velvety thread like lesion, which consists of papules in linear, annular or retiform arrangement. A tiny white elevated dot is present at the intersection of the white lines known as ‘Wickham’s striae’ or ‘Honiton lace’.
An isomorphic response (Koebner’s phenomenon) is common occurrence in LP, and develops in areas previously subjected to some type of trauma (Figure 1). Reticular is the most common type, consisting of slightly raised fine whitish lines in an interlocking lace like keratotic pattern. Papular lesions are small (0.5–1.0 mm) white raised papules. Plaque type closely resembles leukoplakia with a reticular surrounding. Atrophic type appears as inflamed areas of mucosa covered by thin red appearing epithelium. Erosive type presents with atrophic mucosa with ulcers. Bullous form is very rare and is characterized by formation of large thin walled bullae.
Papular, plaque like, atrophic and erosive lesions are very frequently accompanied by reticular lesions. All forms of oral LP are generally asymptomatic, but atrophic, erosive and bullous forms are associated with pain and burning sensation.
Biopsy of the lesion should be done to confirm the diagnosis. In situations where histopathology does not confirm the diagnosis then immunofluorescence studies of biopsy specimens should be done. Direct immunofluorescence demonstrates a shaggy band of fibrinogen in the basement membrane zone in 90–100% of cases. Specimens for immunofluorescence should be stored in Michel’s/Bouin’s solution or normal saline and then sent to histopathology.
|Reticular form||– Lichenoid reactions|
|Plaque form||– Leukoplakia, hyperplastic candidiasis, traumatic keratosis|
|Atrophic form||– Speckled leukoplakia, anemic stomatitis, systematic lupus erythematosus and discord lupus erythematosus|
|Erosive and bullous form||– Vesiculobullous lesions|
|Annular form||– Erythema circinata migrans.|
The role of Candida in the causation of oral LP has been debated, therefore a smear for candida needs to be made and if positive, a topical antifungal—clotrimazole (available as Candid gum paint in India) should be given for 14 days.
Steroid-resistant cases can be treated using topical tacrolimus 0.1% (available as Tacroz and Tacrovate), cyclosporine rinse and systemic hydroxychloroquine sulfate 200 mg o.d. for 3–6 months (available as tablet HCQS).
Epidermolysis bullosa (EB) is a diverse group of disorders that have as a common feature blister formation with tissue separation occurring at variable depths in the skin and/or mucosa depending on the specific EB type. There may be marked oral involvement, potentially creating devastating alterations in the soft and hard tissues. Oral tissue fragility and blistering is common to all EB types.
The current classification proposed for epidermolysis bullosa is mentioned in Chapter 7 on Vesiculobullous Disorders.
Pertaining to hereditary forms pathogenesis appears to be related to genetic defects in basal cells, hemidesmosomes or anchoring connective tissue filaments depending on the disease subtype. The acquired non-hereditary type is often precipitated by exposure to specific drugs, and type VII collagen antibodies located below the lamina densa are found.
An autosomal recessive disorder that appears at birth. Multiple bullae are seen frequently involving the oral mucosa. Extremities develop more bullae which result in scarring that eventually leads to muscular dystrophy and deformity.
An autosomal recessive disorder that develops in neonates within hours after birth. Nail beds are usually the first area of involvement with shedding of nails, remaining skin surface progressively develops bullae. Many infants die within a few months and survivors have nail distortion, growth retardation, anemia, scarring and skin lesions. Large fragile vesicles and bullae are frequently seen in the oral cavity, especially in the posterior hard palate and soft palate. Enamel hypoplasia and enamel pits leading to dental caries are usually seen. Another routinely encountered feature is perioral crusting.
An autosomal dominant form, which is very mild; 20% of patients develop lesions before 1 year of age. Vesicles and bullae begin to develop and gradually lessen with age. Dystrophic nails and scarring is prominent. White mucosal epithelial inclusion cysts may be seen on the tongue, buccal mucosa and palatal mucosa.
Lesions of pemphigus vulgaris, erythema multiforme and dermatitis herpetiformis mimic epidermolysis bullosa. Histopathological and immunofluorescent studies will help in differentiating these conditions.
Individuals with EB can retain their dentition using conventional restorative techniques. With aggressive preventive interventions and management of developing malocclusions using serial extraction, it is also possible to reduce the likelihood of rampant caries, achieve an acceptable occlusion without the need for active tooth movement or appliance therapy, and allow these individuals to benefit from maintaining a natural healthy dentition.
Although the cause of psoriasis is unknown, it is now widely accepted that psoriasis involves an increase in the rate of epithelial cell proliferation. It is proposed that the increased epithelial turnover rate of psoriasis is associated with cell damage.
There also appears to be a strong genetic component to the pathogenesis of psoriasis. Thirty-five percent of patients with psoriasis have a positive family history. Studies on the major histocompatibility complex (MHC) have shown a strong association between B13, Bwl7, Bw37, and Cw6 antigens and development of psoriasis.
Psoriasis is more common in whites and in women. Approximately 10–15% of new cases begin in children younger than 10 years. The median age at onset is 28 years. Typical skin lesions of psoriasis appear as well-circumscribed erythematous patches with overlying thick silvery scales (Figure 2A, B). Lesions may occur in any location, but most commonly involve the scalp and the anterior hairline, torso, bony prominences of the extremities, nails, perianal and perineal areas. The course of the disease is unpredictable and characterized by spontaneous episodes and relapses.
Oral lesions should be treated with topical corticosteroids. The topical steroids that are available in India are triamcinolone acetonide—0.1% with orabase (Kenacort oral paste, TESS cream), clobetasol propionate—0.05% (Clobetamil cream, Tenovate skin cream).
Psoriatic arthritis is a systemic disorder and inflammatory condition and this disease may be the major contributing factor to temporomandibular dysfunction (TMD) symptoms and signs. TMD signs and symptoms are found more frequent and more severe in the patients with psoriatic arthritis of other joints than in the patients with psoriasis without arthritis. TMD signs and symptoms in psoriasis are mainly caused by the related joint involvement that directly affects the masticatory system.
The ectodermal dysplasias comprise a large and heterogeneous group of disorders (about 170) characterized by a variety of congenital defects in structures of ectodermal origin including skin, hair, teeth, nails, and sweat glands. Out of these the most common and best studied disease is anhidrotic or hypohidrotic ectodermal dysplasia (Christ –Siemens –Touraine syndrome).
The condition is characterized by hypodontia, hypotrichosis, and hypohidrosis. Neonates exhibit excessive scaling of the skin and unexplained pyrexia. Patients present with sparse hair and eyebrows (Figure 3A, B).
Figure 3 (A) A boy with sparse scalp hair in ectodermal dysplasia. Courtesy: Dr Sumanth KN. (B) Photograph showing hair loss of the eyebrows and scalp hair. Courtesy: Department of Oral Medicine and Radiology, MCODS, Mangalore
As the age progresses frontal bossing, saddle nose, sunken cheeks, thick/everted lips wrinkled and hyperpigmented skin around the eyes are seen. Patients may present with fever of unknown origin because of the inability to sweat.
Anodontia/oligodontia is often seen. The remaining teeth are usually malformed. Both deciduous and permanent teeth are affected. Most common missing teeth are molars. Malformed teeth have truncated and conical crowns and shortened roots (Figures 4 and 5).
Dry mouth, high palatal arch and cleft palate may be seen in some individuals. The alveolar ridges are usually malformed (Figure 6). Orthopantomograph will help to confirm the absence of teeth (Figure 7).
Distinct condition if all the three components are present. However, for single component of disease the differential diagnosis is isolated oligodontia, Witkop tooth nail syndrome and trichodental syndrome.
The term Ehlers –Danlos syndrome (EDS) was coined after the names of a Danish dermatologist, Edvard Ehlers (1901) and a French dermatologist, Henri Alexandre Danlos (1908) who reported patients exhibiting thin, hyperplastic skin, loose jointedness, and hemorrhagic tendencies.
It is a group of inherited disorders characterized by excessive looseness (laxity) of the joints, hyperelastic skin that is fragile and bruises easily, and/or easily damaged blood vessels. The diagnosis of EDS encompasses any of six types of connective tissue disorders that are hereditary in nature and exhibit a characteristic defect in collagen metabolism.
EDS was initially subdivided into seven types following a meeting of various authors in Berlin, Germany. However owing to its complex nature, another widely accepted classification consisting of six types of EDS was proposed in Villefranche, France in 1997.
Different forms of EDS have different modes of inheritance. Family history is a risk factor in some cases. Various subtypes are inherited as autosomal dominant/recessive and X-linked traits. A variety of genetic mutations cause abnormality in collagen that will result in the disease.
Hypoplasia of the enamel is commonly seen. Premolar and molar teeth can present with deep fissures and long cusps. Microdontia is sometimes present. Irregularities in the dentin structure and dentinal tubules may also be seen.
The tongue is very supple. Approximately, 50% of those with the syndrome can touch the end of their nose with their tongue (Gorlin’s sign), compared to 8–10% of the normal population and the palate is commonly vaulted.
There is no specific cure for EDS, so individual problems and symptoms must be evaluated and cared for appropriately. Genetic counseling is recommended for prospective parents with a family history of EDS.