Etiopathogenesis

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.

Clinical features

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.

Atrophic and erosive lesions involving the gingiva results in desquamative gingivitis which is characterized by bright red areas involving the full width of attached gingiva.

Investigations

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.

Differential diagnosis

Management

The lesions of oral LP appear, regress and reappear in some what unpredictable fashion. Asymptomatic LP need not be treated. The treatment of symptomatic LP is necessary.

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).

Other modes of treating oral LP are topical and systemic retinoids, psoralen ultraviolet A (PUVA) therapy, dapsone, mesalazine and levamisole.

Erosive LP is a premalignant condition with a malignant transformation rate of 0.1–0.3%. It has to be supplemented with systemic vitamin A preparations for chemoprevention.

However most lesions of erosive LP do not respond to conventional steroid therapy unless supplemented by intralesional steroids and especially so if ulcerations are present.

Treatment of oral lichen planus is given in Flowchart 2 on page no 153.

Classification

The current classification proposed for epidermolysis bullosa is mentioned in Chapter 7 on Vesiculobullous Disorders.

Etiopathogenesis

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.

Clinical features

Differential diagnosis

Lesions of pemphigus vulgaris, erythema multiforme and dermatitis herpetiformis mimic epidermolysis bullosa. Histopathological and immunofluorescent studies will help in differentiating these conditions.

Management

Treatment is often frustrating because conventional therapy with corticosteroids and immunosuppressive agents frequently does not result in significant clinical improvement.

Various therapeutic modalities have recently been used which include cyclosporine, colchicine, plasmapheresis, extracorporeal photochemotherapy and intravenous gamma globulins.

Although the data are preliminary, they suggest that intravenous immunoglobulins may be a promising treatment modality for resistant, non-responsive or refractory EB acquisita.

Dental management

The majority of individuals with mild EB subtypes may receive dental treatment with only minor modifications in approach.

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.

Types

Etiopathogenesis

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.

Clinical features

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.

If the deep scales are removed, one or more tiny bleeding points are disclosed, which is popularly referred to as Auspitz’s sign.

The oral counterpart of psoriasis is rare. The first descriptions of oral lesions of psoriasis have been attributed to Oppenheim and Thimm (1903).

Van der Waal and Pindborg described four types of oral psoriatic lesions.

Histopathology

Histopathologically, intraepithelial microabscesses (Munro’s abscesses) are common. However, these are not specific for the disease.

Management

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

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.

Etiopathogenesis

It is an inherited X-linked recessive trait associated with the repressed expression of a gene on the X-chromosome in the positions from q13 to q21.

Clinical features

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).

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.

Oral manifestations

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).

Differential diagnosis

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.

Management

There is no treatment available and the treatment is symptom related. For xerostomia, pilocarpine 5 mg one tab is given three times a day. Salivary substitutes can be used. Crowns for malformed teeth and dental implants for edentulous areas can be recommended.

Villefranche classification of EDS

Etiopathogenesis

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.

Clinical features

Oral manifestations

Scarring on the chin and forehead, a history of repeated luxations of the TMJ, epicanthus, hypertelorism, a narrow curved nose, sparse hair and hyperelasticity of the skin.

Fragile mucosa and gingiva—early-onset generalized periodontitis leading to premature loss of deciduous and permanent teeth. Tooth mobility is often encountered.

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.

Radiographic examination often reveals pulp stones and roots that are short and deformed.

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.

Investigations

Differential diagnosis

Marfan’s syndrome, generalized familial joint hypermobility syndrome, cutis laxa, pseudoxanthoma elasticum and Larsen’s syndrome.

Management

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.

Dental considerations