Uncontrolled Diabetes Can Cause Itching
Yes, uncontrolled diabetes can cause itching through multiple mechanisms, primarily diabetic neuropathy and skin dryness (xerosis). 1, 2
Pathophysiological Mechanisms
Diabetic Neuropathy
- Small fiber neuropathy occurs in diabetes and can lead to regional pruritus, particularly affecting the trunk 1
- Nerve fiber degeneration from diabetic neuropathy can cause localized or generalized pruritus 1
- C-fiber dysfunction, which mediates both pain and pruritus sensations, can occur early in diabetic peripheral neuropathy 1, 3
Skin Changes
- Sudomotor dysfunction (sweat gland impairment) associated with diabetes leads to dry skin and itching 1
- Xerosis (dry skin) is one of the most common cutaneous manifestations in diabetic patients 2
- Changes in cutaneous microvascular blood flow can adversely affect skin quality and structure 1
Epidemiology and Prevalence
- Studies report pruritus prevalence in diabetes ranging from 18.4% to 27.5% 2
- In some regional studies, pruritus has been reported in approximately 7.1% of diabetic patients 4
- Cutaneous manifestations overall occur in up to 76% of diabetic patients 4
Risk Factors for Diabetic Pruritus
Research has identified several risk factors associated with pruritus in type 2 diabetes:
- Advanced age
- Longer duration of diabetes
- Comorbid diabetic peripheral neuropathy
- Comorbid diabetic retinopathy
- Comorbid diabetic kidney disease
- Higher fasting plasma glucose levels 5
Clinical Presentation
- Pruritus may be generalized or localized (commonly truncal) 1
- Often accompanied by sensory symptoms including burning, paraesthesia, stinging, and tingling 1
- May be an early sign of diabetes before diagnosis 2
- Can be exacerbated by poor glycemic control 5
Management Approach
1. Optimize Glycemic Control
- Improving glycemic control is the cornerstone of managing diabetic pruritus 5
- Target appropriate HbA1c levels based on patient factors (though HbA1c may be less reliable in advanced kidney disease) 1
2. Treat Skin Dryness
- Regular use of emollients and moisturizers to combat xerosis 6
- Avoid hot water and harsh soaps that can worsen skin dryness
3. Neuropathic Treatments
For persistent pruritus related to diabetic neuropathy:
- Gabapentin (100-300 mg) may be effective 6
- Pregabalin with doses adjusted according to renal function 6
- Capsaicin topical cream 0.025% applied four times daily 6
4. Address Complications
- Screen for and manage other diabetic complications that may contribute to pruritus, including nephropathy 1, 5
- Consider pruritus as a potential marker for microvascular disease 3
Clinical Significance
Pruritus in diabetic patients should not be dismissed as a minor symptom, as it:
- May indicate poor glycemic control 5
- Could be an early sign of diabetic neuropathy 3
- Significantly impacts quality of life 1
- May warrant diabetes screening in individuals with unexplained chronic itch 2
Common Pitfalls
- Failing to recognize pruritus as a potential sign of uncontrolled diabetes or diabetic complications
- Treating only symptomatically without addressing the underlying glycemic control
- Overlooking the association between pruritus and diabetic neuropathy
- Not considering diabetes as a cause in patients with unexplained chronic pruritus
- Using sedating antihistamines in elderly patients, which may have limited efficacy for neuropathic itch and could increase risk of cognitive side effects 6