Diabetes is a chronic health condition affecting millions worldwide, characterized by elevated blood sugar levels. A frequently reported symptom for many individuals with diabetes is itching. This article explores how high blood sugar, increased susceptibility to skin infections, and broader health complications contribute to this sensation.
How High Blood Sugar Directly Affects Skin
Persistently high blood sugar levels directly impact skin health, contributing to dryness and irritation. Elevated glucose causes the body to excrete excess sugar by drawing fluid from cells, including skin cells, to produce more urine. This process dehydrates the skin, a condition known as xerosis, which manifests as dryness and itching.
High blood sugar can also damage sensory nerve fibers, a condition known as diabetic neuropathy. This nerve damage causes unusual sensations like itching, tingling, or a crawling feeling, even without visible skin changes. Hyperglycemia can trigger inflammatory chemicals called cytokines, stimulating nerve endings and intensifying itching. Reduced blood flow, a consequence of diabetes affecting circulation, further exacerbates dryness and irritation. Poor circulation means skin cells receive fewer nutrients and less oxygen, making skin more prone to itching, especially in the lower legs.
Increased Susceptibility to Skin Infections
Individuals with diabetes often experience heightened susceptibility to skin infections, a significant cause of itching. Elevated glucose in blood and bodily fluids, including sweat, creates an environment favorable for fungi and bacteria. This sugary environment provides a ready food source, allowing microorganisms to thrive and cause infections.
Fungal infections, particularly Candida albicans, are common among people with diabetes and frequently lead to intense itching. These yeast infections often appear as red, itchy rashes with small blisters and scales, typically in warm, moist skin folds like the groin, armpits, or under the breasts. Bacterial infections, such as boils, styes, or folliculitis, are also prevalent and can result in itchy, inflamed lesions. The immune system of people with diabetes can be less effective at fighting invaders, making them vulnerable to persistent infections and associated itching.
Itching from Broader Health Complications
Beyond direct skin effects and infections, itching in diabetes can stem from broader systemic complications. Impaired kidney function, a common long-term complication known as diabetic nephropathy, leads to a buildup of waste products and toxins in the bloodstream. These accumulated substances irritate nerve endings throughout the body, resulting in widespread itching, medically termed uremic pruritus.
When kidneys cannot effectively filter waste, these toxins circulate and trigger nerve signals the brain interprets as an itchy sensation. This itching is often generalized and can occur without visible rash or skin changes. Less common diabetes-related skin conditions, such as eruptive xanthomatosis (small, yellow, itchy bumps), can also contribute to itching, especially when blood sugar is poorly controlled.