Oral candidiasis is commonly called “thrush,”. It is an opportunistic fungal infection that commonly affects the oral mucosa.It is caused by Candida species .The predominant ones are Candida albicans(the commonest), Candida tropicalis, Candida glabrata, Candida guilliermondii, Candida pseudotropicalis, Candida krusei, Candida lusitaniae, Candida parapsilosis, and Candida stellatoidea. C. albicans, C. glabrata, and C. tropicalis are the most common species isolated with C. albicans being the most isolated organism that cause oral candidiasis.
C. albicans is a normal microflora of the body found in the ears, eyes, gastrointestinal tract, mouth, nose, reproductive organs, sinuses, skin, stool and vagina, etc. A change in the microenvironment of these sites cause it to transition into a pathogen.
1. Age : its common in infants and elderly
Antimicrobial proteins in the saliva interact with the oral mucosa and prevent overgrowth of Candida.
• Poor denture hygiene and prolonged wear : for those who wear dentures
• Ill-fitting dentures
• Topical corticosteroid therapy : due to suppression of immunity and phagocytosis
Why do we think smoking is a factor?
Broad-spectrumantibiotics: leads to alteration in local oral flora
• Immunosuppressive therapy:eg systemic corticosteroids, biologic immunomodulating agents,immunosuppressive therapies
•immunocompromising conditions: thymic aplasia, hyper-immunoglobulin E (IgE)/Job’s syndrome, chronic mucocutaneous candidiasis syndromes, Sjogren’s syndrome, graft-versus-host disease, human immunodeficiency virus (HIV)/acquired immune deficiency syndrome (AIDS), leukemia)
• Nutritional deficiencies: iron, zinc, magnesium, selenium, folic acid, vitamins A, B6, B12, and C
• Endocrine dysfunction: diabetes, Addison’s disease, hypothyroidism
Note: Wearing of dentures produces a microenvironment conducive to the growth of candida with low oxygen, low pH and an anaerobic environment. This may be due to enhanced adherence of _Candida sp_. to acrylic, reduced saliva flow under the surfaces of the denture fittings, improperly fitted dentures, or poor oral hygiene.
TYPES OF ORAL CANDIDIASIS
1.Acute Pseudomembranous Candidiasis (Thrush)
This the commonest forms of oropharyngeal candidiasis. They commonly occur as adherent white plaques resembling curdled milk or cottage cheese on the surface of the labial and buccal mucosae, hard and soft palates, tongue, periodontal tissues, and oropharynx. The membrane can be scrapped off with a swab to expose the underlying erythematous mucosa. Pseudomembranous candidiasis is considered the main opportunistic infection in patients with AIDS and cancer, and in patients receiving immunosuppressive therapies.
2. Acute Erythematous: Candidiasis or Acute Atrophic Candidiasis Acute erythematous candidiasis is historically referred to as “antibiotic sore mouth” as it frequently occurs as a consequence of the reduction in levels of the bacterial oral microflora following broad-spectrum antibiotics which facilitates overgrowth of Candida. This form of OC presents as painful reddened lesions throughout the oral cavity It resolves after the antibiotics is stopped. Cessation of antibiotic therapy restores the normal homeostatic balance of the microbial community, which subsequently resolves the infection without the need for therapeutic intervention.
3. Chronic Erythematous:
It presents similarly to the acute form and usually occurs as an extension of it. This form is also often encountered in HIV+ individual.
Angular cheilitis, as the term implies, affects the angles or commissures of the mouth and presents with erythema, maceration, fissuring, crusting, or a combination. The presentation may be unilateral but is more often bilateral. It is usually co-infected with _Staphylococcus aureus_ or _Streptococcal spp_ and, therefore, the exact role that Candida itself plays in the infection is difficult to ascertain. angular cheilitis can be secondary to iron deficiency anemia and vitamin B12 deficiency warranting further investigation with laboratory investigations
5.Chronic Hyperplastic Candidiasis:
It characteristically occurs on the buccal mucosa or lateral border of the tongue(the most common distribution) as a speckled or homogenous white lesion. It is usually associated with smoking,and complete resolution of the infection seems to be dependent on cessation of the habit.This condition can progress to severe dysplasia or malignancy and is also referred to as Candidal leucoplakia-this form is commonly due Epstein-Barr virus reactivation, Unlike acute Pseudomembranous Candidiasis, it cannot be scraped off.