Oral mucosa

The majority of viral infections affecting the oral cavity are caused by the human Herpes Virus group. Each human herpes virus may present differently within the oral cavity. They are more likely to affect immunocompromised patients such as children and the elderly.

• Herpetic Gingivostomatitis: A self-limiting viral infection which is caused by Herpes Simplex Virus-1(HSV-1). It usually presents in young children and is very contagious . It is characterised by the presence of small oral blisters which break down and coalesce into ulcers[18][19]
• Herpes Labialis (Cold Sore):Reactivation of latent Herpes Simplex Virus-1 triggered by sunlight, stress, and hormonal changes. It is characterised by the presence of crusting blisters on the upper lip.[18]
• Chicken Pox: A type of viral infection which is caused by Varicella Zoster Virus and presents in children. Numerous itchy blisters are found on the face and body. Blisters could also be found on inner cheek and palate of the mouth.[18]
• Herpes Zoster/Shingles: Viral infection caused by reactivation of latent Varicella Zoster Virus and found in adults. Patients can present with acute pain before or after the onset of blisters. If viral reactivation occurs in the facial nerve, it can cause Ramsay-Hunt Syndrome in which patients can develop facial paralysis, blisters around the ears and on the tongue, and loss of tongue sensation.[18]
• Hand, Foot, and Mouth Disease: A highly contagious viral infection which infects young children and is caused by Coxsackie Virus A16. It is characterised by presence of small blisters all over the limbs and the mouth.[18]
• Measles: A highly infectious condition which is caused by Measles virus. It most commonly presents in young children who have not been vaccinated. It is characterised by presence of white spots (Koplik's Spots) which rupture to form ulcers on the palate.[18]
• 6. Papillomas and warts/ verrucae They are caused by various strains of the Human Papilloma Virus (HPV) of which there are more than 100 strains but usually due to HPV types 6 and 11 (2). Papillomas are mostly spiky, finger like projections, or cauliflower head rounded lobular shaped. Usually painless and singular. Verrucae usually appear on the lips. Verrucae Vulgaris is associated with HPV types 2 and 4. HPV types 16 and 18, designated high risk due to association with cancers, do not present like this in the oral mucosa but as white patches (1). Multifocal Epithelial Hyperplasia (Heck Disease) is rare, usually familial, swellings appear in multiples and are more common to some Native American and Inuit groups. Verricuform Xanthoma, a rare lesion which may resemble papilloma, is often white due to hyperkeratosis, usually appear in 50-70 year age group, commonly on the gingivae. They may be mistaken for papilloma or verrucous leukoplakia but are benign (1).

• Syphilis- Bacterial infection which is usually sexually transmitted. It is caused by bacteria Treponema Pallidum and it has different types of oral presentation at different stages of the disease.[20][18]

Oral fungal infections are most commonly caused by different Candida species such as Candida Albicans, Candida Glabrata and Candida Tropicalis resulting in oral Candidiasis.[18][21] There are several predisposing factors to fungal infections such as systemic disease for example Diabetes, recent antibiotics, use of steroid inhalers etc . Management includes identifying and addressing contributory factors, the use of topical/systemic anti-fungal agents, oral and denture hygiene instruction.[22]

Different presentations of oral Candidiasis include:

• Pseudomembranous Candidiasis
• Erythematous Candidiasis
• Denture Stomatitis
• Antibiotic Candidiasis
• Angular Cheilitis
• Median Rhomboid Glossitis
• Chronic Hyperplastic Candidiasis
• Chronic Mucocutaneous Candidiasis

• Lichen Planus: A chronic inflammatory disease with different forms of oral presentations. The most classic appearance of Lichen Planus is the presence of white streaks in inner cheek, tongue, and gum. Desquamative Gingivitis can be seen in patients with Lichen Planus. Biopsy is done for definitive diagnosis of Lichen Planus.[18][23]
• Graft versus Host Disease: An autoimmune disease developed following bone marrow transplant in which its oral presentation is similar to Lichen Planus[18][24][25]
• Pemphigus Vulgaris:An autoimmune chronic disease with clinical presentation of formation of superficial and large blisters which then burst into ulcers on the skin or mucous membrane.[18][26]
• Mucous Membrane Pemphigoid: Autoimmune disease which affects only mucous membranes with clinical presentation of hard and rigid blisters which then rupture eventually into deep ulcers.[18][26]
• Cutaneous Lupus Erythematosus: These present as oral discoid lesions which may be present on the inner cheek and behind the lips. White papules may also be present.[18]

• Lichenoid Reaction- Intra-oral lesion which shares the appearance of Lichen Planus but arises due to contact hypersensitivity to certain dental materials or drug-induced.[18][27]

• Frictional Keratosis: This typically presents as white plaques on the oral mucosa due to  mechanical trauma. When the cause of frictional keratosis is removed the white patch may resolve
• Hyperplastic reactive lesions or nodular swellings These occur in the oral mucosa due to low grade inflammation or trauma (1, 2). They develop where the mucosa is subjected to chronic minor irritants, mechanical or infective (4). They most frequently occur on the buccal mucosa (inner cheek) along the occlusal line where the teeth meet and the gingivae (the mucosa which covers the gums); reactive nodules occurring here are specifically categorised as epulides instead of polyps. Also the alveolar ridge (the gum where the teeth erupt up from, or if missing, where they used to be) and the hard palate (roof of the mouth) (1). The most common are fibrous nodules called fibroepithelial polyps and epulides (4). Other hyperplastic reactive hyperplastic lesions include those associated with dentures, and papillomas. However, they are all similar in cause and nature, the overproduction of the cells of the mucosa, primarily the epithelial cells, also fibrous myxoid and low inflamed tissue due to irritation (1). 1.     Fibroepithelial Polyps are usually pale, firm to touch, and painless but further irritation can cause abrasion and then ulceration or bleeding (1). They are sometimes be called fibroma, such as leaf fibroma, a fibroepithelial polyp often occurring under a denture and appears flattened. However, they are not true benign neoplasms (denoted by suffix ~oma), which are similar in appearance but very rare in the mouth (4). 2.     Epulides. The most common epulides are: a)     Fibrous Epulis. These are just fibroepithelial polyps located only on the gingivae (5). b)     Pyogenic Granuloma and Pregnancy Epulis are both vascular rather than fibrous epulides with more dilated blood vessels making them appear darker pink/ red in colour, and soft (2). They may develop more fibrous as they mature. The Pregnancy variant only appears in pregnancy, usually due to plaque and should resolve with better oral hygiene and at the end of the pregnancy if not (1). Pyogenic Granuloma may occur elsewhere in the mouth such as the tongue and lips (3), but are not therefore epulides. c)     Giant Cell Epulis also known as Peripheral Giant Cell Granuloma, are like Fibrous Epulis and occur at the anterior interdental margin, the gum between the teeth at the front (2). They are more common in women. They are often soft round and deep red to purplish blue (1). It is important they are investigated to make are they are not true giant cell granuloma (4). 3.     Papilliary Hyperplasia of the palate (1,3), or Epulis Fissaratum/ Denture-induced Hyperplasia (2,5). The cause may be unknown (1) but there is an association with ill-fitting dentures resulting in irritation to the mucosa, usually by overextended flange, and with poor denture or oral hygiene (2,4). Oral thrush can be present but is not thought to be the cause (1)

• Recurrent Apthous Stomatitis- Recurrent ulceration found in the mouth with a wide variety of predisposing factors. However, the aetiology remains unclear.[28] There are three forms of RAS: Minor, major, and herpetiform. RAS is usually found in non-smokers and those from high socioeconomic background.[18][28]

Neoplastic:

●      Oral Submucous Fibrosis:

This is a condition that involves inflammation of the tissues under the surface. This may cause rigid tissues and difficulty opening the mouth. 

Benign soft tissue neoplasms

1.     Peripheral nerve sheath tumours most commonly are traumatic neuromas, a reactive response to trauma (1), neurilemmoma and neurofibroma which are large growing painless tumours usually found on the tongue (3). Neurofibroma may occur as a benign solitary lesion but can present as multiple lesions associated with (Von Reckllinghausen’s Disease) neurofibromatosis (4). They can be preceded by café au lait pigmentation spots on the skin, and as they grow can become very disfiguring (4). Malignant change can occur in neurofibromatosis but very rarely in single lesion presentation. Mucosal neuromas can be associated with other conditions such as Multiple Endocrine Neoplasia (MEN) Syndrome and may precede thyroid cancer. (1, 4)

2.     Lipoma and fibrolipoma, are tumour of adipose tissue, or fat, giving them a yellow appearance which varies according to fat content (1, 4). They are usually soft, mobile, slow growing painless and occur mostly in middle age or the elderly.

3.     Granular Cell Tumour is also a tumour arising from neural cells, though it was incorrectly thought to arise from muscle cells and therefore previously called Granular Cell Myoblastoma (4), It also is slow growing large painless and occurs mostly in the tongue (1, 3).

4.     Congenital Epulis, also known as Congenital Granular Cell Tumour (but not related to Granular Cell Tumour) occur mostly on the upper gum, the maxillary alveolar ridge, of newborns, predominantly females (4). Rarely, they occur elsewhere, usually the tongue. They are usually self-resolving (1).

5.     Angiomas – vascular tumours: haemangioma, lymphangioma, venus varix (2). Angiomas are difficult to classify as previously they were considered hamartomas, benign tumour-like malformations (6) but there is debate if they are developmental abnormality, true benign tumour or hamartoma, or can be either (1, 4, 5).  Haemangiomas are common in the oral mucosa but can occur in other structures such as salivary glands (4), and can be congenital (from birth) or develop in childhood. Congenital lesions can resolve spontaneously (involute) but those that develop later usually continue to slowly grow. They are usually dark red-purple or blue, soft, sometimes fluctuant (5) and painless. They commonly blanch on pressure. Usually solitary, they can occur as part of syndromes such as Sturge-weber Syndrome affecting the trigeminal nerve. They are at risk of trauma with subsequent excessive bleeding, thrombosis or calcification (2). Lymphangiomas are far less common in the oral mucosa, usually appearing on the tongue, less commonly the lip at birth or in infancy (1, 2, 4). They are colourless to pale pink and may be nodular projections (1) or resemble ‘frog spawn’ domes (2). They can cause macroglossia (enlargement of the tongue) (1, 4). Venous Varix, like varicose vein, usually appear in older people on the lower lip as a blue-purple lump (2).

• Malignant Neoplasms of oral mucosa- Sarcomas

Connective tissue malignancies, sarcomas, are rare in the oral mucosa. Osteosarcoma, chondrosarcoma arise in bone and cartilage, lymphoma in haematological disorders (1). The most common malignancies are carcinomas, overwhelmingly Squamous Cell Carcinoma (SSC) (4). See Oral Cancer.

1. Rhabdomyosarcoma are fast growing destructive swellings usually in the maxilla. It is the most common oral sarcoma in children and adolescents (1), but rare (4).
2. Kaposi Sarcoma is related to the Kaposi Sarcoma Herpes Virus (KSHV) or Human Herpes Virus (HHV-8) viral infection (3). Predominating on the hard palate and gingivae it develops initially as a macule ranging in colour from red, blue, purple to brown or black, becoming nodular as it grows (2, 3, 4). The lesions are highly vascular and can ulcerate and bleed easily; death is usually from opportunistic infections (1). It is usually associated with HIV /AIDS but also less commonly with immunosuppression such as organ donor recipients or prevalent in some communities such as Mediterranean Jews (1). There is no cure (4) but the lesions respond well to Highly Active Antiretroviral Treatment (HAART) drugs (2)