4 min readNew DelhiAug 28, 2026 09:26 AM IST
People often discuss blood sugar in terms of whether they have diabetes, but glucose levels can stay outside the normal range for some time before reaching a diagnostic threshold. During this stage, subtle changes in the body may not produce obvious symptoms, yet they could potentially influence how the body responds to infections.
Fungal infections are one area worth examining, particularly when they keep returning or seem unusually difficult to clear. Elevated glucose can affect several processes involved in the body’s defence against infection, but the relationship between mildly raised blood sugar and fungal infections is not as straightforward as it may appear.
DISCLAIMER: This article is based on information from the public domain and/or the experts we spoke to. Always consult your health practitioner before starting any routine.
This raises an important question for people who have borderline or mildly elevated glucose readings: could their blood sugar be contributing to a greater susceptibility to fungal infections even if they have not been diagnosed with diabetes? We spoke to an expert to understand whether there is a meaningful connection, which fungal infections may be relevant and when recurrent infections should prompt someone to check their blood sugar.
Can mildly elevated blood sugar increase fungal infection risk?
Dr Palleti Siva Karthik Reddy, MBBS, MD General Medicine, FAIG, Consultant Physician at Elite Care Clinic, tells indianexpress.com, “A mild elevation in blood sugar does not automatically mean a person will develop fungal infections, and the strongest evidence is with established or poorly controlled diabetes. However, dysglycaemia can be an early warning sign, particularly when infections are recurrent. Persistently elevated glucose can impair immune cells such as neutrophils and macrophages, reducing the body’s ability to contain infections. Higher glucose availability can also favour the growth and adherence of organisms such as Candida. Therefore, recurrent fungal infections should be considered in the broader clinical context rather than viewed as proof of prediabetes or diabetes.”
Which fungal infections are linked to elevated blood sugar?
The fungal infections most commonly associated with diabetes and elevated blood sugar include candidiasis, particularly recurrent genital or oral candidiasis, as well as fungal infections affecting the skin, feet and nails.
“Dermatophyte infections such as athlete’s foot and ringworm can also be more common. A fungal infection that repeatedly returns, responds poorly to appropriate treatment, or takes unusually long to resolve should prompt an assessment of underlying risk factors, including blood glucose, particularly if the person also has other features such as increased thirst, frequent urination, unexplained weight changes or a family history of diabetes,” reveals Dr Reddy.
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When should recurrent fungal infections prompt blood sugar testing?
“Quick Quiz
See if you can answer this:
When might recurrent fungal infections be a reason to discuss blood sugar testing with a doctor?
A. After exactly two fungal infections, regardless of other factors.
B. Only when a person has never had a fungal infection before.
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C. When infections are recurrent or unusually persistent, particularly if other diabetes risk factors are present.
D. Only when fasting blood sugar is already known to be high.
Reveal the answer
✅ Correct answer: C
Dr Reddy explains that there is no specific number of fungal infections that automatically indicates diabetes. However, recurrent or unusually persistent infections can be a reason to discuss glucose testing with a doctor, particularly when other diabetes risk factors are present. Initial tests may include fasting plasma glucose and HbA1c. If results are borderline or clinical suspicion remains, a 75 g oral glucose tolerance test may provide additional information.
“According to the 2026 American Diabetes Association criteria, prediabetes includes an HbA1c of 5.7-6.4%, fasting glucose of 100-125 mg/dL, or a two-hour glucose of 140–199 mg/dL during an oral glucose tolerance test,” concludes Dr Reddy.
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DISCLAIMER: This article is based on information from the public domain and/or the experts we spoke to. Always consult your health practitioner before starting any routine.
