9: Dermatological Diseases

Dermatological Diseases

Lichen Planus

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.

Andreasen categorized oral LP into six types, namely, reticular, papular, plaque-like, atrophic, erosive, and bullous.

Lichen planus has been associated with various diseases such as hepatitis C, oral cancer, and diabetes mellitus.

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.

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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.

Differential diagnosis
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.

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.

Epidermolysis Bullosa

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.

Clinical features

Psoriasis

Psoriasis is a non-contagious skin disorder that most commonly appears as inflamed, edematous skin lesions covered with a silvery white scale.

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.

Ectodermal Dysplasia

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).

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).

Ehlers–danlos 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.

There are six major types of EDS that are characterized by distinctive features.

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.

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.

Jan 12, 2015 | Posted by in Oral and Maxillofacial Radiology | Comments Off on 9: Dermatological Diseases
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