People with high phosphorus levels in their diet can experience a great deal of itching. This seems to be somewhat common with those with central sensitivity, and is either an electrolyte sensitivity, a result of diet alone, or the result of a genetic issue. 

You can try cutting out high phosphorous foods, or you can supplement with Calcium/Vitamin D supplements. The key here is balancing calcium and phosphorous levels, and the vitamin D helps you absorb the calcium more efficiently. If this is the issue, this supplement should reduce or stop the itching altogether.

You can also try adding Taurine supplements to your vitamin regimen, which helps balance all electrolytes, including calcium and phosphorous. Since most people in general are deficient in magnesium, I recommend Magnesium Taurate, though taurine alone will be just as effective with itching.

Other options for itching include topical Capsaicin Cream, or adding cayenne pepper (if your stomach allows it) to your food, which contains capsaicin. Capsaicin acts by desensitizing nerve endings responsible for itch and pain.Also, adding coconut oil to your lotion can help sooth your itching topically as well. And adding coconut oil to your food may soothe your itching from the inside-out.

Also, a lesser known, but powerful analgesic called Dextromethorphan may help you at low dosages. Dextromethorphan can be found in a gelcap form in the cough medicine aisle at any pharmacy, or paired with guaifenesin. Guaifenesin can work as an effective muscle relaxer for some, but also may dry out your sinuses too much, which may bother you. in which case, pure dextromethorphan will be the ideal medication for you.

Lastly, phosphorus binders prevent the body from absorbing phosphorus from the food that you eat. They help to pass excess phosphorus out of your body,whereby reducing the amount of phosphorus that gets into your blood. Usually phosphate binders are taken within 5 to 10 minutes before or immediately after both meals and snacks. These medications are by prescription only, so you will need to speak to your doctor about this option before trying it. The most common phosphorus binder is  Calcium Acetate.