3 areas of the body where itching can be a sign to pay attention to.

may be related to:

Kidney problems
Blood changes
Metabolic disorders

The kidneys filter toxins from the body. If they don’t work properly, those substances can build up and cause widespread itching.
Associated symptoms that increase worry:

Swelling
Extreme fatigue
Change in the frequency or amount of urination
High blood pressure
Poorly controlled diabetes

Early-stage kidney disease may not cause pain, so itching may be one of the first symptoms.
Other possible causes of persistent itching

In addition to these three scenarios, itching can also be related to:

Anemias and blood disorders
Some types of lymphoma
Hormonal changes (such as hypothyroidism)