Oral Candidiasis-II

What is oral thrush?

Thrush is an infection caused by a yeast germ called Candida spp. The mouth is a common site whereCandida spp. causes infection. Candidal infection in the mouth is called oral thrush. 

Who gets oral thrush?

Small numbers of Candida spp. commonly live on healthy skin and in a healthy mouth. They are usually harmless. Healthy people do not normally get oral thrush. However, certain situations or conditions may cause an overgrowth of Candida spp. which can lead to a bout of oral thrush. These include:

• Being a baby. Oral thrush is quite common in young babies.
• Wearing dentures, especially if they are not taken out at night, not kept clean, or do not fit well and rub on the gums.
• A course of antibiotics. Antibiotics will kill harmless bacteria which live in the mouth. They do not kill Candida spp. which may multiply more easily if there are fewer bacteria around.
• Excessive use of antibacterial mouthwash (for similar reasons to above).
• Taking steroid tablets or inhalers.
• Having a dry mouth due to a lack of saliva. This may occur as a side-effect from certain drugs (such as antidepressants, antipsychotics, chemotherapy), following radiotherapy to the head or neck, or as a symptom of Sjögren's syndrome.
• Having diabetes.
• Having severe anaemia.
• Lacking iron, folate or vitamin B12.
• Having a poor immune system. For example, if you are taking medicines that suppress your immune system, if you have certain cancers, or if you have HIV/AIDS.
• Being frail or in generally poor health.
• Smoking. Smokers are more likely to develop oral thrush.

Oral thrush is not contagious. You cannot pass on oral thrush to other people.

What are the symptoms of oral thrush?

• The classical symptom is white spots that develop in your mouth. The spots may join together to form larger spots called plaques. They may become yellow or grey. If you wipe off a spot, the underlying tissue may be red but it is not usually sore or painful.
• Often there are no white spots. Areas in your mouth may just become red and sore. This more typically occurs if you get thrush after taking antibiotics or steroids.
• Denture wearers may develop an area of persistent redness under a denture.
• You may develop sore, cracked, red areas just outside your mouth. This mainly affects the angle where the upper and lower lips meet (angular stomatitis).
• Some mild oral thrush infections are painless. However, sometimes oral thrush is quite sore and can make eating and drinking uncomfortable. Some babies with oral thrush may drool saliva, or not be able to feed properly because of soreness.
• Taste can be affected in some people with oral thrush.

How is oral thrush diagnosed?

Doctor will usually diagnose oral thrush by typical symptoms and the typical appearance in mouth. No investigations are usually needed to diagnose oral thrush.

However,doctor may sometimes suggest a blood test to look for certain conditions that may make you more likely to develop oral thrush. For example, a blood test to see if you are lacking iron, B12 or folate.

If oral thrush does not respond to treatment (see below), your doctor may suggest that they take a swab from inside your mouth. The swab is then sent to the laboratory to be examined under a microscope. They can also try to grow the Candida spp. in the laboratory.

Occasionally, a biopsy is needed to confirm a diagnosis of oral thrush. A small sample is taken from the white patches inside your mouth and this can be examined under a microscope.

What is the treatment for oral thrush?

Locally applied treatment

For mild oral thrush, the usual treatment that is tried first is miconazole mouth gel for seven days. Sometimes a two-week course is needed. Nystatin drops are another option if miconazole gel cannot be used (for example, if you are known to be allergic to it). 

Follow the instructions in the packet. Basically:

• The gel or drops should be used after you have eaten or drunk.
• Smear a small amount of gel on to the affected areas, with a clean finger, four times a day.
• With the drops, you use a dropper to place the liquid inside your mouth on to the affected areas four times a day.
• Ideally, you should not eat or drink for about 30 minutes after using either the gel or the drops. This helps to prevent the drug from being washed out of your mouth too soon.

Anti-thrush tablets

Tablets that contain a drug called fluconazole can also help to clear fungal and thrush infections from the body. Tablets tend to be used in more severe or serious cases. For example, for people with a poor immune system who develop extensive oral thrush. Tablets are usually prescribed for seven days and this will usually clear oral thrush.

Adjustment of other medication

If you are taking other medication that may have caused oral thrush, such as steroids or antibiotics, your doctor may need to change this medication or reduce the dose to help clear up your thrush.

Other drugs such as itraconazole, ketoconazole or amphotericin can also be used if above drug regime doesn't succeed.

Can oral thrush be prevented?

It may be possible to alter one or more of the situations mentioned above to help prevent further bouts of oral thrush. For example:

• If you have diabetes - good control of your blood sugar level reduces the risk of thrush and other infections.
• If you use steroid inhalers - having a good inhaler technique and using a spacer device may reduce the risk of thrush. Also, rinse your mouth after using the inhaler, to help remove any drug particles left in your mouth. Ask your doctor about reducing your dose of steroid in your inhaler to the lowest level needed to control your asthma.
• If you wear dentures:
  • Leave your dentures out overnight, or for at least six hours daily. Constant wearing of dentures, and not taking them out at night, is thought to be one of the most common causes of oral thrush.
  • Clean and disinfect dentures daily. To clean, use soapy water and scrub the dentures with a soft nailbrush on the fitting surface - that is, the non-polished side. Then soak them in a disinfecting solution. The type of solution and the time they should be soaked for will be advised by your dentist. Rinse the dentures after disinfecting them, and then allow the dentures to air dry before wearing them again. Drying like this helps to kill any Candida spp. that might be stuck to the dentures.
  • Clean the inside of your mouth (where the dentures sit) with a soft brush.
  • See a dentist if the dentures do not fit well.
• If you take medication which causes a dry mouth - take frequent sips of water. (See separate leaflet called 'Dry Mouth' for more details.)
• If you are found to have anaemia or low levels of vitamin B12, folate or iron, treating this may help to prevent oral thrush in the future.
• If you are a smoker, quitting smoking may help to prevent further bouts of oral thrush.
• Certain groups of people may be given anti-thrush tablets to help to prevent oral thrush. For example, people who are on medication to suppress their immune system or who are receiving chemotherapy for cancer.

ORAL CANDIDIASIS (MONILIASIS, THRUSH)-I

Candida albicans is the most frequent cause of fungal human disease in general and very much the most common cause of oral fungal involvement. The organism is a normal inhabitant of the oral cavity in 30 to 40% of the population. When the bacterial flora of the oral cavity is disturbed by antibiotic therapy, or in individuals who have diabetes mellitus, xerostomia (dry-mouth), weakened immunity (for example, AIDS), or severe debilitation, this otherwise harmless microorganism multiplies to cause overt lesions.

The causes and the course the disease:

Oral Candidiasis takes the form of a superficial, curdy, gray to white membrane that can be readily scraped off to reveal an underlying erythematous inflammatory base. In the milder expressions, there is minimal ulceration of the mucosal surface and only a superficial subepithelial inflammatory infiltrate. More severe oral infections may produce mucosal ulceration and a correspondingly greater inflammatory reaction.

In the debilitated, compromised host, the oral candidal infection may be spread into the esophagus by the introduction of a nasogastric tube. Even more threatening, in the vulnerable individual, is more widespread mucous-membrane infection with invasion of the fungi into the deeper tissues of the oral cavity, increasing the potential for bloodstream diffusion. Uncommonly, and in the vulnerable individual, oral candidiasis is followed by widespread mucous membrane infection that has greater potential for invasion and distribution.

The clinical features:

The patient with candidiasis may complain of a burning sensation, tenderness, or sometimes pain around the affected mucosa. Spicy foods will cause occasional discomfort because of the increased sensitivity of the affected mucosa. These infections were more common in women and in patients over 40 years old. Fifty percent of the patients came to them with a chief complaint of oral burning. The patient may report having been on a prolonged course of broad-spectrum antibiotics for a sore throat or other infection.

About oral candidiasis, four major types are recognized: (1) pseudomembranous; (2) hyperplastic; (3) erythematous (atrophic); and (4) angular cheilitis.

The pseudomembranous oral infection may show as fine whitish deposits on an ervthematous patch of mucosa or as more highly developed small, soft, white, slightly raised plaques that closely resemble to milk curds. The disease may range in severity from a single region to a diffuse whitish involvement of several or all the mucosal surfaces. The mucosa next to, or between, these whitish plaques appears red and moderately swollen. The plaques or pseudomembranes may be stripped off the mucosa, leaving a raw bleeding surface. When separate restricted sites are involved, the cheek mucosa and vestibule are the most frequent regions affected—followed by the dorsum of the tongue, palate, gum, floor of the mouth, and lips.

The hyperplastic type is characterized by white plaques which cannot be removed by scraping. The most common location is the cheek mucosa. In patients infected with HIV, the hyperplastic candidiasis most often is found in the lip commissures.

The erythematous (atrophic) type is characterized by a red appearance. The color intensity may vary from fiery red to a hardly distinct pink spot. Common locations are the palate and dorsum of the tongue, as in the so-called multifocal candidiasis in patients who are not infected with HIV but who are heavy smokers. However, erythematous candidiasis may also appear as spotty areas of the cheek mucosa. This is a characteristic feature of the HIV infection, but is often overlooked.

Angular cheilitis is characterized by cracks radiating from the angles of the mouth, often associated with small white plaques.  In the elderly, this is not an unusual lesion and may be because of anemia, loss of chewing vertical dimension, or vitamin deficiency. But it should be remembered that when it is noted in a young man, it could be the first sign of an HIV infection. Today it is recognized the most important etiologic cause is Candida albicans. However, Staphylococcus aureus may also be present in some patients.

The differential diagnosis:

The diagnosis of candidiasis relies on the clinical features and the presence of Candida hyphae on smears examined by potassium hydroxide, periodic acid-Schiff or Gram stain.

As a rule all the keratotic lesions may be readily ruled out from consideration, since they cannot be easily removed by scraping. Necrotic white lesions that must be considered in the differential diagnosis are chemical burns, gangrenous stomatitis, superficial bacterial infections, traumatic ulcers, necrotic ulcers of systemic disease, and the mucous patch.

The mucous patch of syphilis is usually a discrete, small, white necrotic lesion on the tongue, palate, or lips, whereas candidiasis is usually much more diffuse. The accompanying skin lesions of secondary syphilis and the positive serologic findings readily distinguish the mucous patch from candidiasis.

Necrotic ulcers and gangrenous stomatitis of debilitating systemic disease may be difficult to differentiate from candidiasis because the latter entity is usually also found in patients with undermining secondary disease. As a general rule, if the ulcer is deep then candidiasis would not be the primary cause. Traumatic ulcers with necrotic surfaces can often be related to a history of specific trauma. Chemical burns sometimes closely mimic candidiasis. The distinction is usually made by an accurate history, disclosing that a medicament has been applied to the mucosa.

Superficial bacterial infections may occur in patients with debilitating disease and indeed may mimic pseudomembranous candidiasis. Culture of these lesions yielded generous bacteria such as staphylococci, Neisseria, coliform bacteria, and lactobacilli.

The recommended treatment:

The management of patients with oral candidiasis is twofold: (1) to identify, correct, or eliminate predisposing or precipitating causes and (2) to provide antifungal therapy.

The underlying systemic conditions (such as diabetes, malnutrition, and anemia) and the discontinuation of broad-spectrum antibiotics are recommended for the first approaches. Local resistance can be improved by good oral hygiene and by leaving dentures out as much as possible.

The six drugs that are chiefly used for antifungal therapy are gentian violet, nvstatin, amphotericin B, miconazole, clotrimazole, and ketoconazole. Nystatin and amphotericin have been the standard drugs used for oral candidal infections for the last 35 years. Each of these drugs is absorbed poorly from the gastrointestinal tract but is excellent for topical use on mucous membrane and skin lesions.  Most dentists and physicians stress the importance of continuing antifungal therapy at least 2 weeks following disappearance of signs and symptoms of oral lesions.