Oral candidiasis is another complication of diabetes and the condition is caused by a fungus called Candida albicans. The most common etiology of oral candidiasis in individuals with diabetes is xerostomia, and the condition sometimes appears in patients with poor glycemic control. The most common type associated with diabetes is chronic atrophic (erythematous) candidiasis which appears as a red patch or velvet textured plaque. Patients sometimes complain of a burning sensation or an alteration of taste. Smokers and denture-wearers with poor oral hygiene are at greater risk of developing chronic atrophic erythematous candidiasis.
In a large epidemiological study, several oral soft tissue lesions were found to be more prevalent in subjects with type 1 diabetes. The use of antimicrobials, immunosuppressants, or drugs with xerostomic side effects were not related to the presence of the Candida organism. The presence of the candida organism was found to be significantly associated with the use of dentures, cigarette smoking, and poor glycemic control.25
Bartholomew et al. compared the frequency and severity of oral Candida in patients with type 1 diabetes and found that 75% of subjects with diabetes compared to only 35% in the control group. As a result of this study, the authors concluded that individuals with type 1 diabetes are predisposed to oral candidiasis and, that this predisposition is independent of glycemic control.26
In examining individuals with type 2 diabetes, Belazi el al. investigated the potential factors that influence the prevalence of oral Candida in a small sample of patients. Oral Candida was significantly higher in patients with type 2 diabetes compared to healthy subjects, but the researchers ruled out variables such as xerostomia, dentures, age, gender and glycemic control as contributing factors.27
Xerostomia in diabetes is related to structural changes in the parotid glands which creates poor salivary function and sometimes swelling of the parotid glands.28,29 In addition, cigarette smoking, dysgeusia (report of a bad taste), more frequent snacking, xerogenic medications, and elevated fasting blood glucose concentrations have also been significantly associated with decreased salivary flow.
In patients with type 1 diabetes and neuropathy, more cases of xerostomia and decreased salivary flow were reported. A comprehensive evaluation of salivary function is recommended.30