Causes and prevention of skin itching in hemodialysis patients

1. Common causes

Accumulation of uremic toxins

Inadequate clearance of medium-molecular toxins (such as β2-microglobulin) and large-molecular toxins stimulates the nerve endings of the skin.

Inadequate dialysis leads to accumulation of toxins and aggravates skin inflammation.

Calcium-phosphorus metabolism disorder and secondary hyperparathyroidism

Hyperphosphatemia leads to calcium and phosphate deposition, which irritates the skin; elevated parathyroid hormone (PTH) directly stimulates the sensory nerves of the skin.

Dry skin (xeroderma)

Dialysis patients have atrophy of sebaceous glands, decreased sweat gland function, damaged skin barrier, and are easily susceptible to external stimuli.

Immune and inflammatory response

Micro-inflammatory state (such as increased IL-6 and TNF-α) and mast cell activation releasing histamine.

Allergic reactions

Allergy to dialyzer membrane materials (such as AN69 membrane), heparin or ethylene oxide residues.

Neuropathy

Uremia causes peripheral neuropathy, and abnormal sensory conduction causes itching.

Other factors

Iron deficiency, vitamin A excess, combined diabetes or liver disease, etc.

2. Treatment Plan

Treatment should be individualized according to the cause. Common methods include:

Improve dialysis adequacy

Optimize dialysis regimen: extend dialysis time (such as daily dialysis), increase blood flow, and use high-flux dialyzers (which are more effective in removing middle-molecular toxins).

Control calcium and phosphorus metabolism disorders

Phosphorus-lowering treatment : strict low-phosphorus diet (<800 mg/day) + phosphate binders (lanthanum carbonate, sevelamer).

Control PTH : calcimimetics (cinacalcet), active vitamin D (calcitriol), or parathyroidectomy (refractory hyperparathyroidism).

Skin Care & Moisturizing

Use a fragrance-free moisturizer (such as urea cream, petroleum jelly) daily and avoid hot baths and alkaline soaps.

Drug treatment

Antihistamines : Cetirizine, loratadine (limited effectiveness for non-histamine-mediated pruritus).

Gabapentin/pregabalin : Regulates neurogenic pruritus, and the dose needs to be adjusted according to renal function.

κ-opioid receptor agonists : nalfurafine (approved for uremic pruritus in Japan and other regions).

Topical treatment : capsaicin cream (inhibits substance P), tacrolimus ointment (immunomodulatory).

Phototherapy (ultraviolet B radiation)

Relieves itching by suppressing skin inflammation and nerve sensitivity, 2-3 times a week.

Allergy Management

Replace the dialysis membrane with one with good biocompatibility (such as polysulfone membrane) and avoid tubing sterilized with ethylene oxide.

3. Preventive measures

Strict phosphorus control diet

Avoid processed foods, dairy products, nuts and other high-phosphorus foods, and blanch them when cooking to remove phosphorus.

Adequate dialysis and toxin removal

Kt/V and β2-microglobulin levels were assessed regularly, and hemoperfusion or HDF (hemodiafiltration) was used if necessary.

Skin barrier protection

Maintain environmental humidity (40-60%), wear cotton clothing, and avoid scratching to prevent infection.

Regular monitoring indicators

Monitor serum calcium, phosphorus, and PTH monthly to maintain calcium-phosphorus product <55 mg²/dL² and iPTH 150-300 pg/mL.

Psychological interventions

Pruritus is often accompanied by anxiety/depression and requires psychological counseling or drug intervention (such as SSRI drugs).

IV. Handling of special situations

For refractory pruritus , try opioid receptor modulators (eg, naltrexone) or thalidomide (beware of neurotoxicity).

Combined with diabetes : Strengthen blood sugar control, and α-lipoic acid can be used in combination with neuropathic pruritus.

Iron deficiency : IV iron supplementation to achieve ferritin >100 ng/mL and transferrin saturation >20%.