Why does your body itch if you have kidney failure?

It is very common for a patient's whole body to itch if he has kidney failure. “This is because kidney failure makes the skin drier, which in turn makes you feel itchy,” says Dr Manel Vera, a nephrologist at the Hospital Clínic Barcelona. Although the exact process by which this itching occurs is not entirely known, it is considered that another cause may be an imbalance in the body's electrolytes, specifically phosphorus. “If the element phosphorus accumulates to excess, it can typically cause the skin to itch,” explains Dr Vera.

To treat the itchiness, you should adopt good body hydration habits, mainly by applying moisturising creams daily. Regulating the amount of phosphorus ingested through the diet can also help. After consumption, more or less phosphorus is absorbed in the body depending on its origin. For example, only a small part of phosphorus from plants (e.g. legumes or nuts) is absorbed; so it is not considered dangerous to consume these foods a couple of times a week. However, phosphorus of animal origin - meat, fish and dairy products - is more readily absorbed; so you should moderate your daily intake. Finally, synthetic phosphorus (from supplements or industrial foods) is absorbed almost completely; so this intake should be greatly limited and you should check product’s food labels. A common form of phosphorus is as phosphoric acid, which is present in sausages and soft drinks, for example.

More about kidney failure

Kidney failure can lead to chronic kidney failure. It is estimated that some 50,000 people have chronic kidney failure in Spain.

Other symptoms of impaired kidney function are: decreased amount of urine, fluid retention, tiredness, anaemia, bad taste in the mouth, loss of appetite, nausea and vomiting, high blood pressure, increased sensitivity to cold and difficulty breathing.

The diagnosis of kidney failure is made through the glomerular filtration rate (GFR). Values above 90 mL/min are considered normal for glomerular filtration.

What the kidneys do

The kidneys are twin organs responsible for filtering toxins and waste products from the blood and maintaining a balance between the levels of electrolytes (salts in the body) and the amount of water in the body. Substances filtered by the kidneys along with water form urine.

When the kidneys stop filtering properly, these waste products accumulate in the blood and negatively affect the entire body. The kidneys also produce certain hormones. Examples are erythropoietin - involved in blood pressure and the production of red blood cells - and active vitamin D, necessary to absorb calcium from food.