Larr6T Asked :
I am a 53 year old man, diagnosed with diabetes 2 years back and currently on metformin. My sugar levels are quite stable and I always have weekly checks at the pharmacy. For the past 3 months, all readings were at a normal level and I am on a very strict diet. I even lost significant amounts of weight which I know is good for diabetics. I started noticing white spots and patches on my tongue about 2 to 3 weeks ago. They may have been there longer but I did not notice. These patches are whitish-yellow in some areas and very white at other spots.

They are not big – about the size of a pin head to a patch that is about the size of 2 to 3 matchstick heads. It started at the back of my tongue, as far as I could see and now have come more towards the front. It has not yet reached the tip of my tongue but I can now see some spots on the sides of my tongue. My pharmacist said that this may be an yeast infection and has advised me to see my doctor.

I really don’t like going in to the doctor unnecessarily and I was wondering if this is serious? If it is a yeast infection, what could be the worst case scenario if I left it for another 2 to 3 months until I have my regular check up at the doctor. I usually go in for these checkups twice a year. The only other symptom I have noticed is dryness of the mouth, which I know is a symptom of diabetes plus I am a smoker, but there is no increase in urination above the norm.


This question was posted under the Dry Mouth – Causes, Effects, Symptoms, Treatment article.

Any response by the Health Hype team does not constitute a medical consultation and the advice should be viewed purely as a guide. Always consult with your doctor before making any changes to your current treatment program. The information provided in this article is not an authoritative resource on the subject matter and solely intends to guide the reader based on the questions asked and information provided.


Dr. Chris Answered :
Oral thrush, also known as candida of the mouth or oral candidiasis, is an yeast infection of the tongue and mouth this is a possibility given that you are a diabetic. These spots and patches have to be examined by a doctor who will confirm the diagnosis. It is fairly common in immunocompromised patients (refer to Low Immunity) and diabetics are also prone to develop this infection, especially if your diabetes is not well managed. This is what you should be focusing on – the oral thrush may be a strong indicator that your blood glucose levels are not as stable as you think they are.

In terms of your tongue, your strict dieting could be causing vitamin deficiencies which may be causing these symptoms, particularly vitamin B12 and folic acid deficiency. If you are malnourished, your immune system will dip and make you more prone to infections like oral thrush. While you efforts to lose weight is commendable, it is important to ensure that this weight loss is due to your dieting and not a result of other conditions like cancer or HIV infection. Your doctor will be able to verify this.

There are other conditions that can cause white spots and patches on the tongue. If your patches are easily wiped or scraped away, then this could be leukoplakia. If you notice any skin lesions and your are experiencing sensitivity within the mouth, possibly with bleeding, then this could be lichen planus. Tobacco use is a known aggravating factor in both these conditions. Excessive dryness of the mouth, despite your diabetes, can also disrupt the normal microorganisms within your mouth and make it prone to yeast infections.

In terms of the complications of oral thrush, the yeast infection can spread down the throat, into the trachea (wind pipe) or esophagus (food pipe) where it can result in a range of respiratory and gastrointestinal symptoms. This is unlikely unless you are severely immunocompromised and debilitated. However, if this infection is solely due to your uncontrolled blood glucose levels, then you have other more pressing issues that need urgent medical attention.

Weekly finger prick blood tests to monitor your glucose levels are not sufficient. Ideally you should have a home blood glucose monitor and check your glucose levels at least 3 times a day. Recording these results will assist your doctor in making important decisions about the dosage of your medication, conducting further tests or changing your medication. Remember that the complications of diabetes can be life-threatening.

See your doctor immediately and he/she will do an A1C test to assess your blood glucose levels over the preceding months. Try not to treat the oral thrush on your own, without the advice of your doctor, as you may miss more important health issues or even affect the action of your  current diabetes medication.

Also refer to the question and answer article on Extreme Dry Mouth Problem.


Article reviewed by Dr. Greg. Last updated on May 9, 2010