This post summarizes a presentation from the National Kidney Foundation Spring Clinical Meeting.
Speakers: Elizabeth Faust and Giovanna Rosario Arroyo
Skin and wound issues in CKD
Skin disorders are highly prevalent in people living with chronic kidney disease (CKD). Common issues include:
- Approximately 70–80% of individuals with CKD experience dry or itchy skin
- Chronic wounds such as pressure injuries and diabetic foot ulcers are more common in this population
- Calciphylaxis is a CKD-associated vascular calcification disorder that can lead to severe skin necrosis
How CKD affects skin and wound healing
CKD impacts both skin integrity and wound repair through multiple mechanisms:
- Uremic toxins and systemic inflammation impair the skin barrier
- Wound healing is a complex process involving four overlapping phases, all of which may be disrupted in CKD
- Impaired tissue regeneration and chronic inflammation contribute to delayed healing
Common skin conditions in CKD
Xerosis (dry skin)
The most common skin manifestation in CKD, related to reduced skin hydration and barrier dysfunction.
Pruritus (itching)
The second most common condition. CKD-associated pruritus can significantly impact quality of life and sleep. One practical suggestion discussed was the use of mittens at night to reduce skin damage from scratching.
Hyperpigmentation and pallor
Changes in skin colour due to increased melanin production and hemosiderin deposition.
Acquired perforating dermatoses
Skin lesions resulting from chronic scratching and trauma, leading to disruption of collagen structures.
Calciphylaxis
A rare but serious condition primarily seen in end-stage kidney disease (ESKD). It is often associated with severe pain and can initially present as a bruise-like lesion. Over time, lesions may become purpuric, ulcerate, and progress to necrosis. It can be mistaken for a pressure injury, particularly when located on the buttocks.
Why wounds are more common in CKD
Several overlapping factors increase wound risk in CKD:
- High prevalence of diabetes and peripheral vascular disease, leading to impaired blood flow and neuropathy
- Uremic toxins impair immune function
- Protein-energy wasting reduces tissue repair capacity
- Micronutrient deficiencies further impair healing
- Increased hospitalizations and immobility contribute to pressure injury risk
Major types of chronic wounds
1. Pressure injuries
- Caused by prolonged pressure, shear, or immobility
- Often occur in patients with limited mobility, including during long dialysis sessions
- Previously referred to as “bed sores”
2. Diabetic foot ulcers
- Result from a combination of neuropathy, vascular disease, and structural foot changes
- Can be described as “inside-out” pressure injuries due to bone deformities altering pressure distribution
- Often circular with surrounding callus formation
- Frequently associated with peripheral arterial disease
3. Venous leg ulcers
- The most common chronic wound type in the United States
- Caused by chronic venous hypertension and impaired venous return
- Blood pooling in the lower extremities leads to iron deposition, skin discoloration, and eventual breakdown
4. Arterial ulcers
- Caused by ischemia and tissue necrosis
- Typically begin in the toes and may progress proximally
Clinical management of wound types
Pressure injuries
- Offload pressure
- Maintain a clean wound environment
- Use moist wound healing principles
Diabetic foot ulcers
- Improve glycemic control
- Offload pressure
- Provide nutritional support for healing and immune function
Venous leg ulcers
- Compression therapy is first-line treatment
- Encourage leg elevation and mobility
- Use moisture-absorbing dressings due to high exudate
Arterial ulcers
- Keep wounds dry
- Consider vascular referral for revascularization
- Manage comorbidities
Surgical wounds
- Not typically classified as chronic wounds but may heal slowly in CKD
- Optimise nutrition and dialysis adequacy
Calciphylaxis
- Can be misdiagnosed as a pressure injury
- Requires multidisciplinary management
- Includes dialysis optimization and biochemical management
Nutrition and wound healing
Nutrition plays a central role in wound healing.
- Protein-energy wasting impairs collagen synthesis and tissue repair
- Key micronutrients include zinc, vitamin A, and vitamin C
- Nutritional interventions can improve wound outcomes
Nutritional challenges in CKD with wounds
Two major clinical tensions arise:
- Protein: balancing increased protein needs for wound healing with CKD-related protein restriction
- Fluid: balancing increased fluid needs for wound healing with fluid restrictions in CKD
Increased requirements in wound healing
Protein
Protein needs may increase substantially, in some cases by up to 250%, to support tissue repair and immune function.
Fluids
Higher fluid intake may support:
- Oxygen delivery
- Skin turgor
- Nutrient transport
- Waste removal
However, requirements must be individualized in CKD.
Phases of wound healing and nutritional needs
1. Hemostasis
- Energy
- Protein
- Vitamin C
- Vitamin K
- Calcium
- Zinc
- Copper
- Vitamin A
2. Inflammatory phase
- Energy
- Protein
- Vitamin C
- Vitamin K
- Calcium
- Zinc
- Copper
- Vitamin A
3. Proliferative phase
- Protein
- Arginine and glutamine
- Vitamin C
- Calcium
- Vitamin D
- Iron
4. Maturation phase
- Protein
- Energy
Malnutrition and wound risk
Malnutrition significantly increases the risk of developing wounds and delays healing once wounds are present.
Key nutrients in wound healing
Micronutrients
Iron
- Supports collagen synthesis
- Essential for oxygen transport via hemoglobin
Vitamin C
- Antioxidant and enzymatic cofactor
- Supports transition from inflammatory to proliferative healing phases
- Supplementation may be considered in deficient individuals
- Caution in patients prone to calcium oxalate stones
Vitamin A
- Fat-soluble vitamin involved in immune regulation
- Supports epithelial cell growth and repair
Zinc
- Cofactor for multiple enzymes
- Important for granulation tissue formation
- Supplementation alone has not consistently shown benefit in vascular or pressure ulcers
Macronutrients
Calories
- Pressure injury targets often range around 25–30 kcal/kg/day
Protein
- May require temporary relaxation of CKD dietary restrictions during acute wound healing
- Intake may increase to 1.2–1.5 g/kg/day depending on clinical context
Hydration
- Baseline needs often estimated around 30 mL/kg/day
- Must be individualized based on losses (fever, vomiting, diarrhea, wound exudate) and CKD status
Amino acid supplementation
Arginine
- One of the most studied amino acids in wound healing
- Supports collagen production (via proline and hydroxyproline pathways)
- Precursor to nitric oxide, supporting neovascularization
- May enhance immune and growth factor activity
- Common studied dose: ~4.5 g/day for 8 weeks
Glutamine
- Supports arginine and citrulline pathways
- Promotes fibroblast proliferation
- Supports gut mucosal integrity and may reduce inflammatory signalling
Beta-hydroxy-beta-methylbutyrate (HMB)
- Some evidence suggests benefit in diabetic wound healing
- Often studied in combination with arginine and glutamine
Final take-home messages
- Wound prevalence is high in CKD and driven by multiple physiological and vascular factors
- Nutrition plays a central role in wound healing but must be carefully balanced with CKD dietary restrictions
- Protein and fluid requirements often need individualized adjustment during active wound healing
